From a66e58193f7d5801784e11912eeaf10569bbb076 Mon Sep 17 00:00:00 2001
From: alessandro bason <alessandro.bason@zuru.com>
Date: Tue, 24 Jun 2025 17:47:08 +0200
Subject: [PATCH] .

---
 arena.c                    | 136 +++++++++--
 arena.h                    |  37 ++-
 core.h                     |  42 ++--
 net.c                      |  29 ++-
 os.c                       |   2 +-
 os.h                       |   6 +-
 parsers.c                  |  12 +-
 pretty_print.c             |   8 +-
 pretty_print.h             |  10 +-
 str.c                      |  12 +-
 str.h                      |   3 +-
 tests/arena_tests.c        | 237 +++++++++++++++++++
 tests/core_tests.c         | 229 +++++++++++++++++++
 tests/highlight_tests.c    | 179 +++++++++++++++
 tests/net_tests.c          | 238 +++++++++++++++++++
 tests/os_tests.c           | 374 ++++++++++++++++++++++++++++++
 tests/parsers_tests.c      | 370 ++++++++++++++++++++++++++++++
 tests/pretty_print_tests.c |  34 +++
 tests/runner.h             |  41 ++++
 tests/str_tests.c          | 457 +++++++++++++++++++++++++++++++++++++
 tests/string_tests.c       |  12 +
 tools/nob.c                |  15 +-
 tools/unit_tests.c         |  80 +++++++
 win/net_win32.c            |  20 +-
 win/os_win32.c             | 110 ++++++---
 25 files changed, 2600 insertions(+), 93 deletions(-)
 create mode 100644 tests/arena_tests.c
 create mode 100644 tests/core_tests.c
 create mode 100644 tests/highlight_tests.c
 create mode 100644 tests/net_tests.c
 create mode 100644 tests/os_tests.c
 create mode 100644 tests/parsers_tests.c
 create mode 100644 tests/pretty_print_tests.c
 create mode 100644 tests/runner.h
 create mode 100644 tests/str_tests.c
 create mode 100644 tests/string_tests.c
 create mode 100644 tools/unit_tests.c

diff --git a/arena.c b/arena.c
index c52f4e2..e74237d 100644
--- a/arena.c
+++ b/arena.c
@@ -1,8 +1,11 @@
 #include "arena.h"
 
-#include <assert.h>
 #include <string.h>
 
+#if COLLA_DEBUG
+#include <stdlib.h>
+#endif
+
 #include "os.h"
 
 static uptr arena__align(uptr ptr, usize align) {
@@ -25,12 +28,18 @@ arena_t malloc_arena = {
 
 arena_t arena_init(const arena_desc_t *desc) {
     arena_t out = {0};
+
+#if COLLA_DEBUG
+    out.file = desc->file;
+    out.line = desc->line;
+#endif
     
     if (desc) {
         switch (desc->type) {
-            case ARENA_VIRTUAL: out = arena__make_virtual(desc->size); break;
-            case ARENA_MALLOC:  out = arena__make_malloc(desc->size); break;
-            case ARENA_STATIC:  out = arena__make_static(desc->static_buffer, desc->size); break;
+            case ARENA_VIRTUAL:       out = arena__make_virtual(desc->size); break;
+            case ARENA_MALLOC:        out = arena__make_malloc(desc->size); break;
+            case ARENA_STATIC:        out = arena__make_static(desc->static_buffer, desc->size); break;
+            case ARENA_MALLOC_ALWAYS: out = malloc_arena; break;
 		    default: break;  
         }
     }
@@ -76,6 +85,10 @@ void *arena_alloc(const arena_alloc_desc_t *desc) {
             break; 
     }
 
+    if (!ptr && desc->flags & ALLOC_SOFT_FAIL) {
+        return NULL;
+    }
+
     usize total = desc->size * desc->count;
 
     return desc->flags & ALLOC_NOZERO ? ptr : memset(ptr, 0, total);
@@ -98,7 +111,7 @@ void arena_rewind(arena_t *arena, usize from_start) {
         return;
     }
 
-    assert(arena_tell(arena) >= from_start);
+    colla_assert(arena_tell(arena) >= from_start);
 
     arena->cur = arena->beg + from_start;
 }
@@ -137,17 +150,13 @@ static void arena__free_virtual(arena_t *arena) {
         return;
     }
 
-    bool success = os_release(arena->beg, arena_capacity(arena));
-    assert(success && "Failed arena free");
+    os_release(arena->beg, arena_capacity(arena));
 }
 // == MALLOC ARENA =====================================================================================================
 
-extern void *malloc(usize size);
-extern void free(void *ptr);
-
 static arena_t arena__make_malloc(usize size) {
-    u8 *ptr = malloc(size);
-    assert(ptr);
+    u8 *ptr = os_alloc(size);
+    colla_assert(ptr);
     return (arena_t) {
         .beg = ptr,
         .cur = ptr,
@@ -157,7 +166,7 @@ static arena_t arena__make_malloc(usize size) {
 }
 
 static void arena__free_malloc(arena_t *arena) {
-    free(arena->beg);
+    os_free(arena->beg);
 }
 
 // == ARENA ALLOC ======================================================================================================
@@ -171,7 +180,10 @@ static void *arena__alloc_common(const arena_alloc_desc_t *desc) {
 
     if (total > arena_remaining(arena)) {
         if (!soft_fail) {
-            fatal("finished space in arena, tried to allocate %_$$$dB out of %_$$$dB\n", total, arena_remaining(arena));
+#if COLLA_DEBUG
+            arena__print_crash(arena);
+#endif
+            fatal("finished space in arena, tried to allocate %_$$$dB out of %_$$$dB (total: %_$$$dB)\n", total, arena_remaining(arena), (usize)(arena->end - arena->beg));
         }
         return NULL;
     }
@@ -187,10 +199,13 @@ static void *arena__alloc_common(const arena_alloc_desc_t *desc) {
             // TODO is this really correct?
             usize num_of_pages = (extra_mem / page_size) + 1;
 
-            assert(num_of_pages > 0);
+            colla_assert(num_of_pages > 0);
 
             if (!os_commit(arena->cur, num_of_pages + 1)) {
                 if (!soft_fail) {
+#if COLLA_DEBUG
+                    arena__print_crash(arena);
+#endif
                     fatal("failed to commit memory for virtual arena, tried to commit %zu pages\n", num_of_pages);
                 }
                 return NULL;
@@ -201,6 +216,14 @@ static void *arena__alloc_common(const arena_alloc_desc_t *desc) {
     u8 *ptr = arena->cur;
     arena->cur += total;
 
+#if COLLA_DEBUG
+    alloc_header_t *header = calloc(1, sizeof(alloc_header_t));
+    header->size = desc->size;
+    header->count = desc->count;
+    memcpy(header->type_name, desc->type_name.buf, MIN(desc->type_name.len, sizeof(header->type_name)));
+    list_push(arena->head, header);
+#endif
+
     return ptr;
 }
 
@@ -208,9 +231,9 @@ static void *arena__alloc_malloc_always(const arena_alloc_desc_t *desc) {
     usize total = desc->size * desc->count;
 
     // TODO: alignment?
-    u8 *ptr = malloc(total);
+    u8 *ptr = os_alloc(total);
     if (!ptr && !(desc->flags & ALLOC_SOFT_FAIL)) {
-        fatal("malloc call failed for %_$$$dB", total);
+        fatal("alloc call failed for %_$$$dB", total);
     }
 
     return ptr;
@@ -228,3 +251,82 @@ static arena_t arena__make_static(u8 *buf, usize len) {
     };
 }
 
+// == DEBUG ============================================================================================================
+#if COLLA_DEBUG
+
+#define ARENA_HMAP_SIZE (1024)
+
+typedef struct arena_hnode_t arena_hnode_t;
+struct arena_hnode_t {
+    u32 size;
+    u32 count;
+};
+
+typedef struct arena_hmap_t arena_hmap_t;
+struct arena_hmap_t {
+    u64 hashes[ARENA_HMAP_SIZE];
+    char keys[ARENA_HMAP_SIZE][16];
+    arena_hnode_t values[ARENA_HMAP_SIZE];
+};
+
+u64 arena_hmap_hash(char key[16]) {
+    const u8 *data = (const u8 *)key;
+    u64 hash = 0;
+
+    for (usize i = 0; i < 16; ++i) {
+		hash = data[i] + (hash << 6) + (hash << 16) - hash;
+    }
+
+    return hash;
+}
+
+arena_hnode_t *arena_hmap_find_or_add(arena_hmap_t *map, char key[16]) {
+    u64 hash = arena_hmap_hash(key);
+    usize index = hash & (ARENA_HMAP_SIZE - 1);
+
+    usize beg = index;
+    usize end = ARENA_HMAP_SIZE;
+    
+    for (usize k = 0; k < 2; ++k) {
+        for (usize i = index; i < ARENA_HMAP_SIZE; ++i) {
+            if (map->hashes[i] == 0){
+                arena_hnode_t *node = &map->values[i];
+                map->hashes[i] = hash;
+                memcpy(map->keys[i], key, 16);
+                return node;
+            }
+
+            if (map->hashes[i] == hash && memcmp(map->keys[i], key, 16) == 0) {
+                return &map->values[i];
+            }
+        }
+
+        beg = 0;
+        end = index;
+    }
+
+    return NULL;
+}
+
+void arena__print_crash(arena_t *arena) {
+    arena_hmap_t hmap = {0};
+
+    debug("arena %v:%d", arena->file, arena->line);
+
+    for_each (header, arena->head) {
+        arena_hnode_t *node = arena_hmap_find_or_add(&hmap, header->type_name);
+        colla_assert(node->size == 0 || node->size == header->size);
+        node->size = header->size;
+        node->count += header->count;
+    }
+
+    print("type name       | size\t| count\t| total\n");
+    for (usize i = 0; i < ARENA_HMAP_SIZE; ++i) {
+        if (hmap.hashes[i] == 0) continue;
+        arena_hnode_t n = hmap.values[i];
+        print("%16s| %_$$$dB\t| %d\t| %_$$$dB\n", hmap.keys[i], n.size, n.count, n.size * n.count);
+    }
+}
+#endif
+
+
diff --git a/arena.h b/arena.h
index 40b9130..bbfedfa 100644
--- a/arena.h
+++ b/arena.h
@@ -3,6 +3,10 @@
 
 #include "core.h"
 
+#if COLLA_DEBUG
+#include "str.h"
+#endif
+
 #if COLLA_WIN && !COLLA_TCC
 #define alignof __alignof
 #endif
@@ -21,16 +25,36 @@ typedef enum alloc_flags_e {
     ALLOC_SOFT_FAIL  = 1 << 1,
 } alloc_flags_e;
 
+#if COLLA_DEBUG
+typedef struct alloc_header_t alloc_header_t;
+struct alloc_header_t {
+    char type_name[16];
+    u32 size;
+    u32 count;
+    alloc_header_t *next;
+};
+void arena__print_crash(arena_t *arena);
+#endif
+
 typedef struct arena_t arena_t;
 struct arena_t {
     u8 *beg;
     u8 *cur;
     u8 *end;
     arena_type_e type;
+#if COLLA_DEBUG
+    strview_t file;
+    int line;
+    alloc_header_t *head;
+#endif
 };
 
 typedef struct arena_desc_t arena_desc_t;
 struct arena_desc_t {
+#if COLLA_DEBUG
+    strview_t file;
+    int line;
+#endif
     arena_type_e type;
     usize size;
     u8 *static_buffer;
@@ -38,6 +62,9 @@ struct arena_desc_t {
 
 typedef struct arena_alloc_desc_t arena_alloc_desc_t;
 struct arena_alloc_desc_t {
+#if COLLA_DEBUG 
+    strview_t type_name;
+#endif
     arena_t *arena;
     usize count;
     alloc_flags_e flags;
@@ -46,10 +73,18 @@ struct arena_alloc_desc_t {
 };
 
 // arena_type_e type, usize allocation, [ byte *static_buffer ]
+#if !COLLA_DEBUG
 #define arena_make(...) arena_init(&(arena_desc_t){ __VA_ARGS__ })
+#else
+#define arena_make(...) arena_init(&(arena_desc_t){ strv(__FILE__), __LINE__, __VA_ARGS__ })
+#endif
 
 // arena_t *arena, T type, [ usize count, alloc_flags_e flags, usize align, usize size ]
+#if !COLLA_DEBUG
 #define alloc(arenaptr, type, ...) arena_alloc(&(arena_alloc_desc_t){ .size = sizeof(type), .count = 1, .align = alignof(type), .arena = arenaptr, __VA_ARGS__ })
+#else
+#define alloc(arenaptr, type, ...) arena_alloc(&(arena_alloc_desc_t){ .type_name = strv(#type), .size = sizeof(type), .count = 1, .align = alignof(type), .arena = arenaptr, __VA_ARGS__ })
+#endif
 
 // simple arena that always calls malloc internally, this is useful if you need
 // malloc for some reason but want to still use the arena interface
@@ -70,4 +105,4 @@ usize arena_capacity(arena_t *arena);
 void arena_rewind(arena_t *arena, usize from_start);
 void arena_pop(arena_t *arena, usize amount);
 
-#endif
\ No newline at end of file
+#endif
diff --git a/core.h b/core.h
index dd33237..1f9e940 100644
--- a/core.h
+++ b/core.h
@@ -20,21 +20,6 @@ void colla_cleanup(void);
 
 /////////////////////////////////////////////////
 
-// USEFUL MACROS ////////////////////////////////
-
-#define arrlen(a) (sizeof(a) / sizeof((a)[0]))
-#define COLLA_UNUSED(v) (void)(v)
-
-#define MIN(a, b) ((a) < (b) ? (a) : (b))
-#define MAX(a, b) ((a) > (b) ? (a) : (b))
-
-#define KB(n) (((u64)n) << 10)
-#define MB(n) (((u64)n) << 20)
-#define GB(n) (((u64)n) << 30)
-#define TB(n) (((u64)n) << 40)
-
-/////////////////////////////////////////////////
-
 // LINKED LISTS /////////////////////////////////
 
 // singly linked list
@@ -73,7 +58,7 @@ void colla_cleanup(void);
 
 // OS AND COMPILER MACROS ///////////////////////
 
-#if defined(_DEBUG) || !defined(NDEBUG)
+#if defined(_DEBUG) 
     #define COLLA_DEBUG   1
     #define COLLA_RELEASE 0
 #else
@@ -163,6 +148,31 @@ void colla_cleanup(void);
 
 /////////////////////////////////////////////////
 
+// USEFUL MACROS ////////////////////////////////
+
+#define arrlen(a) (sizeof(a) / sizeof((a)[0]))
+#define COLLA_UNUSED(v) (void)(v)
+
+#define COLLA__STRINGIFY(x) #x
+#define COLLA_STRINGIFY(x) COLLA__STRINGIFY(x)
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+#define KB(n) (((u64)n) << 10)
+#define MB(n) (((u64)n) << 20)
+#define GB(n) (((u64)n) << 30)
+#define TB(n) (((u64)n) << 40)
+
+#if COLLA_DEBUG
+    #define colla__assert(file, line, cond, ...) do { if (!(cond)) fatal(file ":" line " ASSERT FAILED: (" COLLA__STRINGIFY(cond) ") " __VA_ARGS__); } while (0)
+    #define colla_assert(...) colla__assert(__FILE__, COLLA__STRINGIFY(__LINE__), __VA_ARGS__)
+#else
+    #define colla_assert(...) (void)0
+#endif
+
+/////////////////////////////////////////////////
+
 // BASIC TYPES //////////////////////////////////
 
 #if COLLA_WIN && COLLA_UNICODE
diff --git a/net.c b/net.c
index 6a511ee..4377fd0 100644
--- a/net.c
+++ b/net.c
@@ -1,6 +1,8 @@
 #include "net.h" 
 #include "arena.h" 
 
+#include <stdio.h> // sscanf
+
 #if COLLA_WIN
 #include "win/net_win32.c"
 #else
@@ -38,7 +40,7 @@ const char *http_get_status_string(int status) {
         case 404: return "NOT FOUND";               
         case 407: return "RANGE NOT SATISFIABLE";   
 
-        case 500: return "INTERNAL SERVER_ERROR";   
+        case 500: return "INTERNAL SERVER ERROR";   
         case 501: return "NOT IMPLEMENTED";         
         case 502: return "BAD GATEWAY";             
         case 503: return "SERVICE NOT AVAILABLE";   
@@ -54,6 +56,11 @@ http_header_t *http__parse_headers_instream(arena_t *arena, instream_t *in) {
 
     while (!istr_is_finished(in)) {
         strview_t line = istr_get_line(in);
+        
+        // end of headers
+        if (strv_is_empty(line)) {
+            break;
+        }
 
         usize pos = strv_find(line, ':', 0);
         if (pos != STR_NONE) {
@@ -112,7 +119,7 @@ http_res_t http_parse_res(arena_t *arena, strview_t response) {
     http_res_t res = {0};
     instream_t in = istr_init(response);
 
-    strview_t http = istr_get_view_len(&in, 5);
+    strview_t http = istr_get_view_len(&in, 4);
     if (!strv_equals(http, strv("HTTP"))) {
         err("response doesn't start with 'HTTP', instead with %v", http);
         return (http_res_t){0};
@@ -258,7 +265,7 @@ str_t http_decode_url_safe(arena_t *arena, strview_t string) {
         }
     }
 
-    assert(final_len <= string.len);
+    colla_assert(final_len <= string.len);
 
     str_t out = {
         .buf = alloc(arena, char, final_len + 1),
@@ -531,7 +538,7 @@ sha1_result_t sha1(sha1_t *ctx, const void *buf, usize len) {
     return result;
 }
 
-str_t sha1Str(arena_t *arena, sha1_t *ctx, const void *buf, usize len) {
+str_t sha1_str(arena_t *arena, sha1_t *ctx, const void *buf, usize len) {
     sha1_result_t result = sha1(ctx, buf, len);
     return str_fmt(arena, "%08x%08x%08x%08x%08x", result.digest[0], result.digest[1], result.digest[2], result.digest[3], result.digest[4]);
 }
@@ -623,10 +630,20 @@ buffer_t base64_decode(arena_t *arena, buffer_t buffer) {
         bytes[2] = (triple >>  0) & 0xFF;
     }
 
+    usize spaces_count = 0;
+    for (isize i = buffer.len - 1; i >= 0; --i) {
+        if (buffer.data[i] == '=') {
+            spaces_count++;
+        }
+        else {
+            break;
+        }
+    }
+
     usize outlen = arena_tell(arena) - start;
 
     return (buffer_t){
         .data = out,
-        .len = outlen,
+        .len = outlen - spaces_count,
     };
-}
\ No newline at end of file
+}
diff --git a/os.c b/os.c
index aef91b8..cae0952 100644
--- a/os.c
+++ b/os.c
@@ -149,7 +149,7 @@ buffer_t os_file_read_all_fp(arena_t *arena, oshandle_t handle) {
 str_t os_file_read_all_str(arena_t *arena, strview_t path) {
 	oshandle_t fp = os_file_open(path, FILEMODE_READ);
 	if (!os_handle_valid(fp)) {
-		err("could not open file %v", path);
+		err("could not open file %v: %v", path, os_get_error_string(os_get_last_error()));
 		return STR_EMPTY;
 	}
 	str_t out = os_file_read_all_str_fp(arena, fp);
diff --git a/os.h b/os.h
index 0488fc1..c1208b5 100644
--- a/os.h
+++ b/os.h
@@ -118,6 +118,7 @@ bool os_dir_create(strview_t folder);
 tstr_t os_file_fullpath(arena_t *arena, strview_t filename);
 void os_file_split_path(strview_t path, strview_t *dir, strview_t *name, strview_t *ext);
 bool os_file_delete(strview_t path);
+bool os_dir_delete(strview_t path);
 
 oshandle_t os_file_open(strview_t path, filemode_e mode);
 void os_file_close(oshandle_t handle);
@@ -193,7 +194,10 @@ bool os_run_cmd(arena_t scratch, os_cmd_t *cmd, os_env_t *optional_env);
 oshandle_t os_run_cmd_async(arena_t scratch, os_cmd_t *cmd, os_env_t *optional_env);
 bool os_process_wait(oshandle_t proc, uint time, int *out_exit);
 
-// == VMEM ======================================
+// == MEMORY ====================================
+
+void *os_alloc(usize size);
+void os_free(void *ptr);
 
 void *os_reserve(usize size, usize *out_padded_size);
 bool os_commit(void *ptr, usize num_of_pages);
diff --git a/parsers.c b/parsers.c
index e98ef49..57b3fc5 100644
--- a/parsers.c
+++ b/parsers.c
@@ -374,12 +374,12 @@ void json_pretty_print(json_t *root, const json_pretty_opts_t *options) {
     }
     if (!default_options.use_custom_colours) {
         os_log_colour_e default_col[JSON_PRETTY_COLOUR__COUNT] = {
-            LOG_COL_YELLOW, // JSON_PRETTY_COLOUR_KEY,
-            LOG_COL_CYAN,   // JSON_PRETTY_COLOUR_STRING,
-            LOG_COL_BLUE,   // JSON_PRETTY_COLOUR_NUM,
-            LOG_COL_BLACK,  // JSON_PRETTY_COLOUR_NULL,
-            LOG_COL_GREEN,  // JSON_PRETTY_COLOUR_TRUE,
-            LOG_COL_RED,    // JSON_PRETTY_COLOUR_FALSE,
+            LOG_COL_YELLOW,    // JSON_PRETTY_COLOUR_KEY,
+            LOG_COL_CYAN,      // JSON_PRETTY_COLOUR_STRING,
+            LOG_COL_BLUE,      // JSON_PRETTY_COLOUR_NUM,
+            LOG_COL_DARK_GREY, // JSON_PRETTY_COLOUR_NULL,
+            LOG_COL_GREEN,     // JSON_PRETTY_COLOUR_TRUE,
+            LOG_COL_RED,       // JSON_PRETTY_COLOUR_FALSE,
         };
         memmove(default_options.colours, default_col, sizeof(default_col));
     }
diff --git a/pretty_print.c b/pretty_print.c
index 38275a1..bbe23a9 100644
--- a/pretty_print.c
+++ b/pretty_print.c
@@ -1,10 +1,8 @@
 #include "pretty_print.h"
 
 #include <stdarg.h>
-#include "core.h"
-#include "os.h"
-#include "str.h"
 
+#include "core.h"
 
 strview_t pretty__colour[LOG_COL__COUNT] = {
     [LOG_COL_BLACK]         = cstrv("black"),
@@ -28,6 +26,10 @@ strview_t pretty__colour[LOG_COL__COUNT] = {
     [LOG_COL_RESET]         = cstrv("/"),
 };
 
+strview_t pretty_log_to_colour(os_log_colour_e colour) {
+    return pretty__colour[colour];
+}
+
 void pretty_print(arena_t scratch, const char *fmt, ...) {
     va_list args;
     va_start(args, fmt);
diff --git a/pretty_print.h b/pretty_print.h
index 35e88c1..bd5c35a 100644
--- a/pretty_print.h
+++ b/pretty_print.h
@@ -1,14 +1,10 @@
 #pragma once
 
-#if 0
-
-pretty_print(arena,
-        "<red>error!</><blue>%s!</>", "wow");
-
-#endif
-
+#include "os.h"
 #include "arena.h"
+#include "str.h"
 
+strview_t pretty_log_to_colour(os_log_colour_e colour);
 void pretty_print(arena_t scratch, const char *fmt, ...);
 void pretty_printv(arena_t scratch, const char *fmt, va_list args);
 
diff --git a/str.c b/str.c
index 7b29b19..f6dae95 100644
--- a/str.c
+++ b/str.c
@@ -1,5 +1,7 @@
 #include "str.h"
 
+#include "os.h"
+
 #include <limits.h>
 #include <math.h>
 #include <stdlib.h>
@@ -396,7 +398,11 @@ bool char_is_num(char c) {
 }
 
 char char_lower(char c) {
-    return c >= 'A' && c <= 'Z' ? c - 32 : c;
+    return c >= 'A' && c <= 'Z' ? c + 32 : c;
+}
+
+char char_upper(char c) {
+    return c <= 'a' && c >= 'z' ? c - 32 : c;
 }
 
 // == INPUT STREAM =================================================
@@ -657,9 +663,11 @@ char ostr_back(outstream_t *ctx) {
 str_t ostr_to_str(outstream_t *ctx) {
     ostr_putc(ctx, '\0');
 
+    usize len = ostr_tell(ctx);
+
     str_t out = {
         .buf = ctx->beg,
-        .len = ostr_tell(ctx) - 1,
+        .len = len ? len - 1 : 0,
     };
 
     memset(ctx, 0, sizeof(outstream_t));
diff --git a/str.h b/str.h
index 13ef068..8e5b398 100644
--- a/str.h
+++ b/str.h
@@ -1,8 +1,6 @@
 #ifndef COLLA_STR_H
 #define COLLA_STR_H
 
-#include <string.h> // strlen
-
 #include "core.h"
 #include "darr.h"
 
@@ -165,6 +163,7 @@ bool char_is_space(char c);
 bool char_is_alpha(char c);
 bool char_is_num(char c);
 char char_lower(char c);
+char char_upper(char c);
 
 // == INPUT STREAM =================================================
 
diff --git a/tests/arena_tests.c b/tests/arena_tests.c
new file mode 100644
index 0000000..3523e51
--- /dev/null
+++ b/tests/arena_tests.c
@@ -0,0 +1,237 @@
+#include "../arena.h"
+#include "../os.h"
+#include "../core.h"
+
+#include "runner.h"
+
+UNIT_TEST(arena_init_virtual) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, MB(1));
+    ASSERT(arena.type == ARENA_VIRTUAL);
+    ASSERT(arena.beg != NULL);
+    ASSERT(arena.cur == arena.beg);
+    ASSERT(arena.end == arena.beg + MB(1));
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_init_malloc) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    ASSERT(arena.type == ARENA_MALLOC);
+    ASSERT(arena.beg != NULL);
+    ASSERT(arena.cur == arena.beg);
+    ASSERT(arena.end == arena.beg + KB(4));
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_init_malloc_always) {
+    arena_t arena = arena_make(ARENA_MALLOC_ALWAYS, KB(4));
+    ASSERT(arena.type == ARENA_MALLOC_ALWAYS);
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_init_static) {
+    u8 buffer[KB(4)];
+    arena_t arena = arena_make(ARENA_STATIC, KB(4), buffer);
+    ASSERT(arena.type == ARENA_STATIC);
+    ASSERT(arena.beg == buffer);
+    ASSERT(arena.cur == arena.beg);
+    ASSERT(arena.end == arena.beg + KB(4));
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_alloc_basic) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, MB(1));
+    int *ptr = alloc(&arena, int);
+    ASSERT(ptr != NULL);
+    *ptr = 42;
+    ASSERT(*ptr == 42);
+    ASSERT(arena.cur > arena.beg);
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_alloc_array) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, MB(1));
+    int *arr = alloc(&arena, int, .count = 10);
+    ASSERT(arr != NULL);
+    for (int i = 0; i < 10; i++) {
+        arr[i] = i;
+    }
+    for (int i = 0; i < 10; i++) {
+        ASSERT(arr[i] == i);
+    }
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_alloc_custom_align) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, MB(1));
+    void *ptr = alloc(&arena, char, .align = 64);
+    ASSERT(ptr != NULL);
+    ASSERT(((uintptr_t)ptr & 63) == 0); // Should be 64-byte aligned
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_alloc_nozero) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, MB(1));
+    int *ptr1 = alloc(&arena, int);
+    ASSERT(*ptr1 == 0); // Default zeroed
+    
+    int *ptr2 = alloc(&arena, int, .flags = ALLOC_NOZERO);
+    // We can't assert on the value as it's uninitialized
+    ASSERT(ptr2 != NULL);
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_alloc_soft_fail) {
+    u8 buffer[10];
+    arena_t arena = arena_make(ARENA_STATIC, 10, buffer);
+    
+    void *ptr1 = alloc(&arena, char, .count = 5);
+    ASSERT(ptr1 != NULL);
+    
+    // This would normally fail, but with SOFT_FAIL it returns NULL
+    void *ptr2 = alloc(&arena, char, .count = 10, .flags = ALLOC_SOFT_FAIL);
+    ASSERT(ptr2 == NULL);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_scratch) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, MB(1));
+    arena_t scratch = arena_scratch(&arena, KB(1));
+    
+    ASSERT(scratch.beg != NULL);
+    ASSERT(scratch.type == ARENA_STATIC);
+    
+    void *ptr = alloc(&scratch, int);
+    ASSERT(ptr != NULL);
+    
+    // Scratch cleanup happens implicitly when parent arena is cleaned up
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_tell) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, MB(1));
+    usize pos1 = arena_tell(&arena);
+    ASSERT(pos1 == 0);
+    
+    alloc(&arena, int);
+    usize pos2 = arena_tell(&arena);
+    ASSERT(pos2 > pos1);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_remaining) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, KB(64));
+    usize initial_remaining = arena_remaining(&arena);
+    ASSERT(initial_remaining == KB(64));
+    
+    alloc(&arena, char, .count = KB(4));
+    usize after_alloc = arena_remaining(&arena);
+    ASSERT(after_alloc < initial_remaining);
+    ASSERT(after_alloc >= KB(60)); // Account for possible alignment padding
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_capacity) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, KB(64));
+    usize cap = arena_capacity(&arena);
+    ASSERT(cap == KB(64));
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_rewind) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, MB(1));
+    
+    usize mark = arena_tell(&arena);
+    
+    int *ptr1 = alloc(&arena, int);
+    *ptr1 = 42;
+    
+    alloc(&arena, char, .count = 100);
+    
+    arena_rewind(&arena, mark);
+    
+    int *ptr2 = alloc(&arena, int);
+    ASSERT(ptr2 == ptr1); // Should reuse the same memory
+    
+    // Original value is lost after rewind
+    *ptr2 = 24;
+    ASSERT(*ptr2 == 24);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_pop) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, MB(1));
+    
+    alloc(&arena, char, .count = 100);
+    usize pos = arena_tell(&arena);
+    
+    alloc(&arena, char, .count = 50);
+    
+    arena_pop(&arena, 50);
+    ASSERT(arena_tell(&arena) == pos);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_malloc_arena) {
+    void *ptr = alloc(&malloc_arena, int);
+    ASSERT(ptr != NULL);
+    
+    // We need to free each allocation from malloc_arena manually
+    os_free(ptr);
+}
+
+UNIT_TEST(arena_alloc_mixed_types) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, MB(1));
+    
+    int *i = alloc(&arena, int);
+    float *f = alloc(&arena, float);
+    char *c = alloc(&arena, char);
+    
+    *i = 42;
+    *f = 3.14f;
+    *c = 'A';
+    
+    ASSERT(*i == 42);
+    ASSERT(*f == 3.14f);
+    ASSERT(*c == 'A');
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(arena_multiple_arenas) {
+    arena_t arena1 = arena_make(ARENA_VIRTUAL, KB(4));
+    arena_t arena2 = arena_make(ARENA_VIRTUAL, KB(4));
+    
+    int *ptr1 = alloc(&arena1, int);
+    int *ptr2 = alloc(&arena2, int);
+    
+    *ptr1 = 42;
+    *ptr2 = 24;
+    
+    ASSERT(*ptr1 == 42);
+    ASSERT(*ptr2 == 24);
+    
+    arena_cleanup(&arena1);
+    arena_cleanup(&arena2);
+}
+
+UNIT_TEST(arena_stress_test) {
+    arena_t arena = arena_make(ARENA_VIRTUAL, MB(10));
+    
+    // Allocate many objects
+    for (int i = 0; i < 1000; i++) {
+        int *ptr = alloc(&arena, int);
+        ASSERT(ptr != NULL);
+        *ptr = i;
+    }
+    
+    // Allocate a large block
+    void *large = alloc(&arena, char, .count = MB(5));
+    ASSERT(large != NULL);
+    
+    arena_cleanup(&arena);
+}
diff --git a/tests/core_tests.c b/tests/core_tests.c
new file mode 100644
index 0000000..de6b3fb
--- /dev/null
+++ b/tests/core_tests.c
@@ -0,0 +1,229 @@
+#include "runner.h"
+#include "../core.h"
+#include <stdio.h>
+#include <assert.h>
+
+UNIT_TEST(arrlen_macro) {
+    int array[5] = {1, 2, 3, 4, 5};
+    ASSERT(arrlen(array) == 5);
+    
+    char str[] = "hello";
+    ASSERT(arrlen(str) == 6); // Including null terminator
+}
+
+UNIT_TEST(min_max_macros) {
+    ASSERT(MIN(5, 10) == 5);
+    ASSERT(MIN(-5, 10) == -5);
+    ASSERT(MIN(5.5, 10.1) == 5.5);
+    
+    ASSERT(MAX(5, 10) == 10);
+    ASSERT(MAX(-5, 10) == 10);
+    ASSERT(MAX(5.5, 10.1) == 10.1);
+}
+
+UNIT_TEST(size_constants) {
+    ASSERT(KB(1) == 1024);
+    ASSERT(MB(1) == 1024 * 1024);
+    ASSERT(GB(1) == 1024 * 1024 * 1024);
+    ASSERT(TB(1) == 1024ULL * 1024ULL * 1024ULL * 1024ULL);
+    
+    ASSERT(KB(2) == 2048);
+    ASSERT(MB(2) == 2 * 1024 * 1024);
+}
+
+UNIT_TEST(linked_list) {
+    // Define a simple node structure
+    typedef struct Node {
+        int value;
+        struct Node *next;
+    } Node;
+    
+    // Create some nodes
+    Node n1 = {1, NULL};
+    Node n2 = {2, NULL};
+    Node n3 = {3, NULL};
+    
+    // Initialize list
+    Node *list = NULL;
+    
+    // Push nodes onto list
+    list_push(list, &n3);
+    list_push(list, &n2);
+    list_push(list, &n1);
+    
+    // Check list order
+    ASSERT(list == &n1);
+    ASSERT(list->next == &n2);
+    ASSERT(list->next->next == &n3);
+    ASSERT(list->next->next->next == NULL);
+    
+    // Pop from list
+    list_pop(list);
+    ASSERT(list == &n2);
+    ASSERT(list->next == &n3);
+    
+    list_pop(list);
+    ASSERT(list == &n3);
+    
+    list_pop(list);
+    ASSERT(list == NULL);
+}
+
+UNIT_TEST(double_linked_list) {
+    // Define a double linked node
+    typedef struct DNode {
+        int value;
+        struct DNode *next;
+        struct DNode *prev;
+    } DNode;
+    
+    // Create some nodes
+    DNode n1 = {1, NULL, NULL};
+    DNode n2 = {2, NULL, NULL};
+    DNode n3 = {3, NULL, NULL};
+    
+    // Initialize list
+    DNode *list = NULL;
+    
+    // Push nodes
+    dlist_push(list, &n3);
+    dlist_push(list, &n2);
+    dlist_push(list, &n1);
+    
+    // Check list structure
+    ASSERT(list == &n1);
+    ASSERT(list->next == &n2);
+    ASSERT(list->next->next == &n3);
+    ASSERT(list->prev == NULL);
+    ASSERT(list->next->prev == &n1);
+    ASSERT(list->next->next->prev == &n2);
+    
+    // Pop middle node
+    dlist_pop(list, &n2);
+    
+    // Check updated structure
+    ASSERT(list == &n1);
+    ASSERT(list->next == &n3);
+    ASSERT(list->next->prev == &n1);
+    
+    // Pop first node
+    dlist_pop(list, &n1);
+    ASSERT(list == &n3);
+    ASSERT(list->prev == NULL);
+}
+
+UNIT_TEST(ordered_linked_list) {
+    // Define a simple node
+    typedef struct ONode {
+        int value;
+        struct ONode *next;
+    } ONode;
+    
+    // Create nodes
+    ONode n1 = {1, NULL};
+    ONode n2 = {2, NULL};
+    ONode n3 = {3, NULL};
+    
+    // Initialize head and tail
+    ONode *head = NULL;
+    ONode *tail = NULL;
+    
+    // Push nodes in order
+    olist_push(head, tail, &n1);
+    ASSERT(head == &n1);
+    ASSERT(tail == &n1);
+    
+    olist_push(head, tail, &n2);
+    ASSERT(head == &n1);
+    ASSERT(tail == &n2);
+    ASSERT(head->next == &n2);
+    
+    olist_push(head, tail, &n3);
+    ASSERT(head == &n1);
+    ASSERT(tail == &n3);
+    ASSERT(head->next == &n2);
+    ASSERT(head->next->next == &n3);
+}
+
+UNIT_TEST(for_each_macro) {
+    // Define a simple node
+    typedef struct Node {
+        int value;
+        struct Node *next;
+    } Node;
+    
+    // Create linked list
+    Node n1 = {1, NULL};
+    Node n2 = {2, NULL};
+    Node n3 = {3, NULL};
+    
+    n1.next = &n2;
+    n2.next = &n3;
+    
+    Node *list = &n1;
+    
+    // Use for_each to sum values
+    int sum = 0;
+    for_each(it, list) {
+        sum += it->value;
+    }
+    
+    ASSERT(sum == 6); // 1 + 2 + 3
+}
+
+UNIT_TEST(fmt_print) {
+    // This function outputs to stdout, so we can't easily test its output
+    // Just verify it doesn't crash and returns a positive value
+    int result = fmt_print("Test %d %s\n", 42, "hello");
+    ASSERT(result > 0);
+}
+
+UNIT_TEST(fmt_buffer) {
+    char buffer[128];
+    
+    // Basic formatting
+    int result = fmt_buffer(buffer, sizeof(buffer), "Int: %d", 42);
+    ASSERT(result > 0);
+    ASSERT(strcmp(buffer, "Int: 42") == 0);
+    
+    // Multiple arguments
+    result = fmt_buffer(buffer, sizeof(buffer), "%s %d %.2f", "Test", 123, 3.14159);
+    ASSERT(result > 0);
+    ASSERT(strcmp(buffer, "Test 123 3.14") == 0);
+    
+    // Buffer size limiting
+    result = fmt_buffer(buffer, 5, "Long text that won't fit");
+    ASSERT(result == 24); // fmt_buffer returns the lenght if it did fit
+    ASSERT(strlen(buffer) == 4);
+}
+
+// Helper function to test variadic function
+int test_fmt_printv(const char *fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    int result = fmt_printv(fmt, args);
+    va_end(args);
+    return result;
+}
+
+UNIT_TEST(fmt_printv) {
+    // Just verify it doesn't crash and returns positive value
+    int result = test_fmt_printv("Test %d %s\n", 42, "hello");
+    ASSERT(result > 0);
+}
+
+// Helper function to test variadic function
+int test_fmt_bufferv(char *buf, usize len, const char *fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    int result = fmt_bufferv(buf, len, fmt, args);
+    va_end(args);
+    return result;
+}
+
+UNIT_TEST(fmt_bufferv) {
+    char buffer[128];
+    int result = test_fmt_bufferv(buffer, sizeof(buffer), "%d %s", 42, "test");
+    ASSERT(result > 0);
+    ASSERT(strcmp(buffer, "42 test") == 0);
+}
diff --git a/tests/highlight_tests.c b/tests/highlight_tests.c
new file mode 100644
index 0000000..216ba8c
--- /dev/null
+++ b/tests/highlight_tests.c
@@ -0,0 +1,179 @@
+#include "runner.h"
+#include "../highlight.h"
+#include "../arena.h"
+#include <stdio.h>
+
+UNIT_TEST(highlight_init) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    // Create a basic configuration
+    hl_config_t config = {0};
+    
+    // Define custom colors
+    config.colors[HL_COLOR_NORMAL] = strv_init("normal");
+    config.colors[HL_COLOR_KEYWORDS] = strv_init("keyword");
+    config.colors[HL_COLOR_STRING] = strv_init("string");
+    config.colors[HL_COLOR_COMMENT] = strv_init("comment");
+    
+    // Initialize highlighter
+    hl_ctx_t *ctx = hl_init(&arena, &config);
+    ASSERT(ctx != NULL);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(highlight_basic) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    // Create a configuration
+    hl_config_t config = {0};
+    
+    // Define custom colors for HTML output
+    config.colors[HL_COLOR_NORMAL] = strv_init("color:black");
+    config.colors[HL_COLOR_KEYWORDS] = strv_init("color:blue");
+    config.colors[HL_COLOR_STRING] = strv_init("color:green");
+    config.colors[HL_COLOR_COMMENT] = strv_init("color:gray");
+    config.colors[HL_COLOR_NUMBER] = strv_init("color:purple");
+    
+    // Set HTML output flag
+    config.flags = HL_FLAG_HTML;
+    
+    // Initialize highlighter
+    hl_ctx_t *ctx = hl_init(&arena, &config);
+    ASSERT(ctx != NULL);
+    
+    // Sample C code to highlight
+    strview_t code = strv_init(
+        "// This is a comment\n"
+        "int main() {\n"
+        "    printf(\"Hello, World!\\n\");\n"
+        "    return 0;\n"
+        "}\n"
+    );
+    
+    // Highlight the code
+    str_t highlighted = hl_highlight(&arena, ctx, code);
+    
+    // Verify the output
+    ASSERT(!str_is_empty(highlighted));
+    
+    // We can't easily test the exact output without parsing HTML,
+    // but we can check that key strings are present
+    const char *html_start = "<span";
+    ASSERT(strstr(highlighted.buf, html_start) != NULL);
+    
+    // Check if comment coloring is present
+    ASSERT(strstr(highlighted.buf, "// This is a comment") != NULL);
+    
+    // Check if string highlighting is present
+    ASSERT(strstr(highlighted.buf, "Hello, World!") != NULL);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(highlight_custom_keywords) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    // Create configuration
+    hl_config_t config = {0};
+    
+    // Define colors
+    config.colors[HL_COLOR_NORMAL] = strv_init("normal");
+    config.colors[HL_COLOR_KEYWORDS] = strv_init("keyword");
+    config.colors[HL_COLOR_CUSTOM_TYPES] = strv_init("custom-type");
+    
+    // Define custom keywords
+    hl_keyword_t custom_keywords[] = {
+        {.keyword = strv_init("MyClass"), .color = HL_COLOR_CUSTOM_TYPES},
+        {.keyword = strv_init("custom_func"), .color = HL_COLOR_FUNC}
+    };
+    
+    config.extra_kwrds = custom_keywords;
+    config.kwrds_count = 2;
+    
+    // Initialize highlighter
+    hl_ctx_t *ctx = hl_init(&arena, &config);
+    ASSERT(ctx != NULL);
+    
+    // Test code with custom keywords
+    strview_t code = strv_init(
+        "MyClass obj;\n"
+        "custom_func(obj);\n"
+    );
+    
+    // Highlight the code
+    str_t highlighted = hl_highlight(&arena, ctx, code);
+    
+    // Verify output contains our code
+    ASSERT(!str_is_empty(highlighted));
+    ASSERT(strstr(highlighted.buf, "MyClass") != NULL);
+    ASSERT(strstr(highlighted.buf, "custom_func") != NULL);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(highlight_add_keyword) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    // Create configuration
+    hl_config_t config = {0};
+    
+    // Define colors
+    config.colors[HL_COLOR_NORMAL] = strv_init("normal");
+    config.colors[HL_COLOR_KEYWORDS] = strv_init("keyword");
+    config.colors[HL_COLOR_CUSTOM_TYPES] = strv_init("custom-type");
+    
+    // Initialize highlighter
+    hl_ctx_t *ctx = hl_init(&arena, &config);
+    ASSERT(ctx != NULL);
+    
+    // Add a custom keyword after initialization
+    hl_keyword_t new_keyword = {
+        .keyword = strv_init("NewKeyword"),
+        .color = HL_COLOR_CUSTOM_TYPES
+    };
+    
+    hl_add_keyword(&arena, ctx, &new_keyword);
+    
+    // Test code with the new keyword
+    strview_t code = strv_init("NewKeyword x;\n");
+    
+    // Highlight the code
+    str_t highlighted = hl_highlight(&arena, ctx, code);
+    
+    // Verify output contains our code
+    ASSERT(!str_is_empty(highlighted));
+    ASSERT(strstr(highlighted.buf, "NewKeyword") != NULL);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(highlight_symbol_table) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    // Create configuration
+    hl_config_t config = {0};
+    
+    // Define colors
+    config.colors[HL_COLOR_NORMAL] = strv_init("normal");
+    config.colors[HL_COLOR_SYMBOL] = strv_init("symbol");
+    
+    // Initialize highlighter
+    hl_ctx_t *ctx = hl_init(&arena, &config);
+    ASSERT(ctx != NULL);
+    
+    // Set '@' as a symbol
+    hl_set_symbol_in_table(ctx, '@', true);
+    
+    // Test code with the symbol
+    strview_t code = strv_init("@decorator\n");
+    
+    // Highlight the code
+    str_t highlighted = hl_highlight(&arena, ctx, code);
+    
+    // Verify output contains our code
+    ASSERT(!str_is_empty(highlighted));
+    ASSERT(strstr(highlighted.buf, "@") != NULL);
+    
+    arena_cleanup(&arena);
+}
diff --git a/tests/net_tests.c b/tests/net_tests.c
new file mode 100644
index 0000000..dde2d11
--- /dev/null
+++ b/tests/net_tests.c
@@ -0,0 +1,238 @@
+#include "runner.h"
+#include "../net.h"
+#include "../arena.h"
+#include <stdio.h>
+
+// Initialization Tests
+UNIT_TEST(net_init_cleanup) {
+    net_init();
+    // Simple test to make sure initialization succeeds
+    ASSERT(net_get_last_error() == 0);
+    net_cleanup();
+}
+
+// HTTP Method/Status Tests
+UNIT_TEST(http_method_strings) {
+    ASSERT(strcmp(http_get_method_string(HTTP_GET), "GET") == 0);
+    ASSERT(strcmp(http_get_method_string(HTTP_POST), "POST") == 0);
+    ASSERT(strcmp(http_get_method_string(HTTP_HEAD), "HEAD") == 0);
+    ASSERT(strcmp(http_get_method_string(HTTP_PUT), "PUT") == 0);
+    ASSERT(strcmp(http_get_method_string(HTTP_DELETE), "DELETE") == 0);
+}
+
+UNIT_TEST(http_status_strings) {
+    ASSERT(strcmp(http_get_status_string(200), "OK") == 0);
+    ASSERT(strcmp(http_get_status_string(404), "NOT FOUND") == 0);
+    ASSERT(strcmp(http_get_status_string(500), "INTERNAL SERVER ERROR") == 0);
+}
+
+// HTTP Headers Tests
+UNIT_TEST(http_headers) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    // Parse headers
+    strview_t header_str = strv_init("Content-Type: application/json\r\nUser-Agent: Colla\r\n");
+    http_header_t *headers = http_parse_headers(&arena, header_str);
+    
+    // Check headers were parsed correctly
+    ASSERT(headers != NULL);
+
+    // Headers are parsed in reverse order
+    ASSERT(strv_equals(headers->key, strv_init("User-Agent")));
+    ASSERT(strv_equals(headers->value, strv_init("Colla")));
+    ASSERT(strv_equals(headers->next->key, strv_init("Content-Type")));
+    ASSERT(strv_equals(headers->next->value, strv_init("application/json")));
+
+    // Test header operations
+    ASSERT(http_has_header(headers, strv_init("Content-Type")));
+    ASSERT(!http_has_header(headers, strv_init("Accept")));
+    
+    strview_t content_type = http_get_header(headers, strv_init("Content-Type"));
+    ASSERT(strv_equals(content_type, strv_init("application/json")));
+    
+    // Don't try to free headers as they're allocated in the arena
+    arena_cleanup(&arena);
+}
+
+// HTTP Request/Response Parsing Tests
+UNIT_TEST(http_request_parsing) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    strview_t req_str = strv_init(
+        "GET /index.html HTTP/1.1\r\n"
+        "Host: example.com\r\n"
+        "User-Agent: Colla\r\n"
+        "\r\n"
+    );
+    
+    http_req_t req = http_parse_req(&arena, req_str);
+    
+    ASSERT(req.method == HTTP_GET);
+    ASSERT(req.version.major == 1);
+    ASSERT(req.version.minor == 1);
+    ASSERT(strv_equals(req.url, strv("index.html")));
+    
+    ASSERT(http_has_header(req.headers, strv_init("Host")));
+    ASSERT(strv_equals(http_get_header(req.headers, strv_init("Host")), strv_init("example.com")));
+    
+    // Convert back to string
+    str_t req_out = http_req_to_str(&arena, &req);
+    ASSERT(!str_is_empty(req_out));
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(http_response_parsing) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    strview_t res_str = strv_init(
+        "HTTP/1.1 200 OK\r\n"
+        "Content-Type: text/html\r\n"
+        "Content-Length: 13\r\n"
+        "\r\n"
+        "Hello, World!"
+    );
+    
+    http_res_t res = http_parse_res(&arena, res_str);
+    
+    ASSERT(res.status_code == 200);
+    ASSERT(res.version.major == 1);
+    ASSERT(res.version.minor == 1);
+    ASSERT(strv_equals(res.body, strv_init("Hello, World!")));
+    
+    ASSERT(http_has_header(res.headers, strv_init("Content-Type")));
+    ASSERT(strv_equals(http_get_header(res.headers, strv_init("Content-Type")), strv_init("text/html")));
+    
+    // Convert back to string
+    str_t res_out = http_res_to_str(&arena, &res);
+    ASSERT(!str_is_empty(res_out));
+    
+    arena_cleanup(&arena);
+}
+
+// URL Encoding/Decoding Tests
+UNIT_TEST(http_url_encoding) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    strview_t original = strv_init("hello world & special chars: ?=&/");
+    str_t encoded = http_make_url_safe(&arena, original);
+    str_t decoded = http_decode_url_safe(&arena, strv_init_str(encoded));
+    
+    ASSERT(!str_is_empty(encoded));
+    ASSERT(str_equals(decoded, str_init(&arena, "hello world & special chars: ?=&/")));
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(http_url_splitting) {
+    strview_t url = strv_init("http://example.com/path?query=value");
+    http_url_t split = http_split_url(url);
+
+    ASSERT(strv_equals(split.host, strv_init("example.com")));
+    ASSERT(strv_equals(split.uri, strv_init("/path?query=value")));
+}
+
+// HTTP Request Tests
+// Note: These tests would actually make network requests, so we should mock them
+// for real unit tests. Here we'll just test the setup part.
+UNIT_TEST(http_request_setup) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    // Prepare headers
+    http_header_t headers[2] = {
+        { .key = strv_init("Content-Type"), .value = strv_init("application/json"), .next = &headers[1] },
+        { .key = strv_init("User-Agent"), .value = strv_init("Colla Test"), .next = NULL }
+    };
+    
+    // Setup request descriptor
+    http_request_desc_t desc = {
+        .arena = &arena,
+        .url = strv_init("http://example.com"),
+        .version = { .major = 1, .minor = 1 },
+        .request_type = HTTP_GET,
+        .headers = headers,
+        .header_count = 2,
+        .body = strv_init("")
+    };
+    
+    // We don't actually make the request, just verify the setup is correct
+    ASSERT(desc.arena == &arena);
+    ASSERT(strv_equals(desc.url, strv_init("http://example.com")));
+    ASSERT(desc.request_type == HTTP_GET);
+    ASSERT(desc.headers == headers);
+    ASSERT(desc.header_count == 2);
+    
+    arena_cleanup(&arena);
+}
+
+// Socket Tests
+UNIT_TEST(socket_basic) {
+    net_init();
+    
+    // Open a socket
+    socket_t sock = sk_open(SOCK_TCP);
+    ASSERT(sk_is_valid(sock));
+    
+    // Close the socket
+    ASSERT(sk_close(sock));
+    
+    net_cleanup();
+}
+
+// SHA1 Tests
+UNIT_TEST(sha1_hash) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    sha1_t ctx = sha1_init();
+    
+    const char *data = "Hello, World!";
+    str_t hash = sha1_str(&arena, &ctx, data, strlen(data));
+    
+    // The SHA1 hash for "Hello, World!" is known
+    // But we'll just verify it's not empty and has the expected format (40 hex chars)
+    ASSERT(!str_is_empty(hash));
+    ASSERT(hash.len == 40);
+    
+    arena_cleanup(&arena);
+}
+
+// Base64 Tests
+UNIT_TEST(base64_encoding) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    const char *original = "Hello, World!";
+    buffer_t input = { (u8*)original, strlen(original) };
+    
+    // Encode
+    buffer_t encoded = base64_encode(&arena, input);
+    ASSERT(encoded.data != NULL);
+    ASSERT(encoded.len > 0);
+    
+    // Decode
+    buffer_t decoded = base64_decode(&arena, encoded);
+
+    ASSERT(decoded.data != NULL);
+    ASSERT(decoded.len == input.len);
+    ASSERT(memcmp(decoded.data, input.data, input.len) == 0);
+    
+    arena_cleanup(&arena);
+}
+
+// WebSocket Tests
+UNIT_TEST(websocket_encoding) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    strview_t message = strv_init("Hello, WebSocket!");
+    
+    // Encode message to WebSocket format
+    buffer_t encoded = websocket_encode(&arena, message);
+    ASSERT(encoded.data != NULL);
+    ASSERT(encoded.len > 0);
+    
+    // Decode WebSocket message
+    str_t decoded = websocket_decode(&arena, encoded);
+    ASSERT(!str_is_empty(decoded));
+    ASSERT(str_equals(decoded, str_init(&arena, "Hello, WebSocket!")));
+    
+    arena_cleanup(&arena);
+}
diff --git a/tests/os_tests.c b/tests/os_tests.c
new file mode 100644
index 0000000..33a72c3
--- /dev/null
+++ b/tests/os_tests.c
@@ -0,0 +1,374 @@
+#include "runner.h"
+#include "../os.h"
+#include "../arena.h"
+#include <stdio.h>
+
+// Handle Tests
+UNIT_TEST(os_handle) {
+    oshandle_t zero = os_handle_zero();
+    ASSERT(!os_handle_valid(zero));
+    
+    // Create a handle (using file open)
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    strview_t test_file = strv_init("test_file.txt");
+    
+    // Create test file
+    oshandle_t h_write = os_file_open(test_file, FILEMODE_WRITE);
+    ASSERT(os_handle_valid(h_write));
+    os_file_puts(h_write, strv_init("test content"));
+    os_file_close(h_write);
+    
+    // Open the file and test handle functions
+    oshandle_t h_read = os_file_open(test_file, FILEMODE_READ);
+    ASSERT(os_handle_valid(h_read));
+    ASSERT(!os_handle_match(h_read, zero));
+    
+    oshandle_t h_read2 = os_file_open(test_file, FILEMODE_READ);
+    ASSERT(os_handle_valid(h_read2));
+    ASSERT(!os_handle_match(h_read, h_read2));
+    
+    os_file_close(h_read);
+    os_file_close(h_read2);
+    os_file_delete(test_file);
+    
+    arena_cleanup(&arena);
+}
+
+// File Operations Tests
+UNIT_TEST(os_file_basic) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    strview_t test_file = strv_init("test_file.txt");
+    
+    // Delete if exists
+    if (os_file_exists(test_file)) {
+        os_file_delete(test_file);
+    }
+    
+    // Check existence
+    ASSERT(!os_file_exists(test_file));
+    
+    // Create and write
+    oshandle_t h_write = os_file_open(test_file, FILEMODE_WRITE);
+    ASSERT(os_handle_valid(h_write));
+    
+    os_file_putc(h_write, 'H');
+    os_file_puts(h_write, strv_init("ello World"));
+    
+    os_file_close(h_write);
+    
+    // Check existence after creation
+    ASSERT(os_file_exists(test_file));
+    
+    // Read back
+    oshandle_t h_read = os_file_open(test_file, FILEMODE_READ);
+    ASSERT(os_handle_valid(h_read));
+    
+    char buffer[12] = {0};
+    usize read = os_file_read(h_read, buffer, 11);
+    ASSERT(read == 11);
+    ASSERT(strcmp(buffer, "Hello World") == 0);
+    
+    os_file_close(h_read);
+    
+    // Clean up
+    os_file_delete(test_file);
+    ASSERT(!os_file_exists(test_file));
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(os_file_seek) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    strview_t test_file = strv_init("test_file.txt");
+    
+    // Create and write
+    oshandle_t h_write = os_file_open(test_file, FILEMODE_WRITE);
+    ASSERT(os_handle_valid(h_write));
+    
+    os_file_puts(h_write, strv_init("ABCDEFGHIJ"));
+    os_file_close(h_write);
+    
+    // Open for reading
+    oshandle_t h_read = os_file_open(test_file, FILEMODE_READ);
+    ASSERT(os_handle_valid(h_read));
+    
+    // Seek to position 5
+    ASSERT(os_file_seek(h_read, 5));
+    
+    // Read from position 5
+    char buffer[6] = {0};
+    usize read = os_file_read(h_read, buffer, 5);
+    ASSERT(read == 5);
+    ASSERT(strcmp(buffer, "FGHIJ") == 0);
+    
+    // Rewind and read from beginning
+    os_file_rewind(h_read);
+    
+    char buffer2[6] = {0};
+    read = os_file_read(h_read, buffer2, 5);
+    ASSERT(read == 5);
+    ASSERT(strcmp(buffer2, "ABCDE") == 0);
+    
+    // Test file position
+    ASSERT(os_file_tell(h_read) == 5);
+    
+    // Test file size
+    ASSERT(os_file_size(h_read) == 10);
+    
+    // Seek to end
+    ASSERT(os_file_seek_end(h_read));
+    ASSERT(os_file_is_finished(h_read));
+    
+    os_file_close(h_read);
+    os_file_delete(test_file);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(os_file_read_write_all) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    strview_t test_file = strv_init("test_file.txt");
+    
+    // Write string
+    strview_t test_data = strv_init("This is test data for read/write all functions");
+    ASSERT(os_file_write_all_str(test_file, test_data));
+    
+    // Read back as string
+    str_t read_data = os_file_read_all_str(&arena, test_file);
+    ASSERT(str_equals(read_data, str_init(&arena, "This is test data for read/write all functions")));
+    
+    // Read as buffer
+    buffer_t buffer = os_file_read_all(&arena, test_file);
+    ASSERT(buffer.len == test_data.len);
+    ASSERT(memcmp(buffer.data, test_data.buf, test_data.len) == 0);
+    
+    // Write buffer
+    const char *new_data = "New buffer data";
+    buffer_t write_buffer = {(u8*)new_data, strlen(new_data)};
+    ASSERT(os_file_write_all(test_file, write_buffer));
+    
+    // Read back after buffer write
+    str_t read_new = os_file_read_all_str(&arena, test_file);
+    ASSERT(str_equals(read_new, str_init(&arena, "New buffer data")));
+    
+    // Clean up
+    os_file_delete(test_file);
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(os_file_path) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    // Test path splitting
+    strview_t path = strv_init("/path/to/file.txt");
+    strview_t dir, name, ext;
+    
+    os_file_split_path(path, &dir, &name, &ext);
+
+    ASSERT(strv_equals(dir, strv_init("/path/to")));
+    ASSERT(strv_equals(name, strv_init("file")));
+    ASSERT(strv_equals(ext, strv_init(".txt")));
+    
+    // Test full path resolution
+    strview_t relative_path = strv_init("test_file.txt");
+    tstr_t full_path = os_file_fullpath(&arena, relative_path);
+    
+    // Can't easily test the exact value, but can verify it's not empty
+    ASSERT(full_path.len > 0);
+    
+    arena_cleanup(&arena);
+}
+
+// Directory Tests
+UNIT_TEST(os_dir_operations) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    strview_t test_dir = strv_init("test_dir");
+    
+    // Delete if exists
+    if (os_dir_exists(test_dir)) {
+        os_dir_delete(test_dir);
+    }
+    
+    // Create directory
+    ASSERT(os_dir_create(test_dir));
+    ASSERT(os_dir_exists(test_dir));
+    
+    // Create test file in directory
+    strview_t test_file_path = strv_init("test_dir/test_file.txt");
+    oshandle_t h_write = os_file_open(test_file_path, FILEMODE_WRITE);
+    ASSERT(os_handle_valid(h_write));
+    os_file_puts(h_write, strv_init("test content"));
+    os_file_close(h_write);
+    
+    // Test directory listing
+    dir_t *dir = os_dir_open(&arena, test_dir);
+    ASSERT(os_dir_is_valid(dir));
+    
+    bool found_file = false;
+    dir_foreach(&arena, entry, dir) {
+        if (str_equals(entry->name, str_init(&arena, "test_file.txt"))) {
+            found_file = true;
+            ASSERT(entry->type == DIRTYPE_FILE);
+            ASSERT(entry->file_size == 12); // "test content"
+        }
+    }
+    
+    ASSERT(found_file);
+    
+    // Clean up
+    os_file_delete(test_file_path);
+    os_dir_close(dir);
+    
+    // Directory should now be empty, so we can delete it
+    os_dir_delete(test_dir);
+    ASSERT(!os_dir_exists(test_dir));
+    
+    arena_cleanup(&arena);
+}
+
+// Environment Variable Tests
+UNIT_TEST(os_env_vars) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    arena_t scratch = arena_make(ARENA_MALLOC, KB(1));
+    
+    // Set environment variable
+    strview_t key = strv_init("COLLA_TEST_VAR");
+    strview_t value = strv_init("test_value");
+    
+    os_set_env_var(scratch, key, value);
+    
+    // Get environment variable
+    str_t read_value = os_get_env_var(&arena, key);
+    ASSERT(str_equals(read_value, str_init(&arena, "test_value")));
+    
+    // Get all environment variables
+    os_env_t *env = os_get_env(&arena);
+    ASSERT(env != NULL);
+    
+    arena_cleanup(&scratch);
+    arena_cleanup(&arena);
+}
+
+// Virtual Memory Tests
+UNIT_TEST(os_virtual_memory) {
+    usize page_size;
+    void *memory = os_reserve(MB(1), &page_size);
+    ASSERT(memory != NULL);
+    ASSERT(page_size > 0);
+    
+    // Commit a page
+    ASSERT(os_commit(memory, 1));
+    
+    // Write to the committed memory
+    memset(memory, 0x42, os_get_system_info().page_size);
+    
+    // Release the memory
+    ASSERT(os_release(memory, MB(1)));
+}
+
+// Thread Tests
+static int thread_test_func(u64 thread_id, void *userdata) {
+    int *value = (int*)userdata;
+    (*value)++;
+    return 42;
+}
+
+UNIT_TEST(os_thread) {
+    // Create thread data
+    int value = 0;
+    
+    // Launch thread
+    oshandle_t thread = os_thread_launch(thread_test_func, &value);
+    ASSERT(os_handle_valid(thread));
+    
+    // Get thread ID
+    u64 thread_id = os_thread_get_id(thread);
+    ASSERT(thread_id != 0);
+    
+    // Join thread
+    int exit_code;
+    ASSERT(os_thread_join(thread, &exit_code));
+    ASSERT(exit_code == 42);
+    ASSERT(value == 1);
+}
+
+int test_mutex_trylock(u64 id, void *userdata) {
+    oshandle_t mutex = *((oshandle_t*)userdata);
+    return os_mutex_try_lock(mutex);
+}
+
+
+// Mutex Tests
+UNIT_TEST(os_mutex) {
+    oshandle_t mutex = os_mutex_create();
+    ASSERT(os_handle_valid(mutex));
+
+    oshandle_t thread = os_thread_launch(test_mutex_trylock, &mutex);
+    
+    // Lock mutex
+    os_mutex_lock(mutex);
+    
+    int locked = 0;
+    os_thread_join(thread, &locked);
+    ASSERT(locked == false);
+    
+    // Unlock
+    os_mutex_unlock(mutex);
+    
+    // Try lock should succeed now
+    ASSERT(os_mutex_try_lock(mutex));
+    
+    // Unlock again
+    os_mutex_unlock(mutex);
+    
+    // Free mutex
+    os_mutex_free(mutex);
+}
+
+#if !COLLA_NO_CONDITION_VARIABLE
+// Condition Variable Tests
+struct cond_test_data {
+    oshandle_t mutex;
+    oshandle_t cond;
+    int counter;
+};
+
+static int cond_test_thread(u64 thread_id, void *userdata) {
+    struct cond_test_data *data = (struct cond_test_data*)userdata;
+    
+    os_mutex_lock(data->mutex);
+    data->counter++;
+    os_mutex_unlock(data->mutex);
+    
+    // Signal the condition
+    os_cond_signal(data->cond);
+    
+    return 0;
+}
+
+UNIT_TEST(os_condition_variable) {
+    struct cond_test_data data;
+    data.mutex = os_mutex_create();
+    data.cond = os_cond_create();
+    data.counter = 0;
+    
+    // Lock mutex before launching thread
+    os_mutex_lock(data.mutex);
+    
+    // Launch thread
+    oshandle_t thread = os_thread_launch(cond_test_thread, &data);
+    
+    // Wait for condition with timeout
+    os_cond_wait(data.cond, data.mutex, 1000);
+    
+    // We should have the lock again, and counter should be 1
+    ASSERT(data.counter == 1);
+    
+    // Unlock and cleanup
+    os_mutex_unlock(data.mutex);
+    os_thread_join(thread, NULL);
+    
+    os_mutex_free(data.mutex);
+    os_cond_free(data.cond);
+}
+#endif
diff --git a/tests/parsers_tests.c b/tests/parsers_tests.c
new file mode 100644
index 0000000..8004fe6
--- /dev/null
+++ b/tests/parsers_tests.c
@@ -0,0 +1,370 @@
+#include "runner.h"
+#include "../parsers.h"
+#include "../arena.h"
+#include <stdio.h>
+
+// INI Parser Tests
+UNIT_TEST(ini_parse_basic) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    strview_t ini_content = strv_init(
+        "[section1]\n"
+        "key1=value1\n"
+        "key2=value2\n"
+        "\n"
+        "[section2]\n"
+        "key3=value3\n"
+        "key4=value4\n"
+    );
+    
+    ini_t ini = ini_parse_str(&arena, ini_content, NULL);
+    ASSERT(ini_is_valid(&ini));
+    
+    // Test section1
+    initable_t *section1 = ini_get_table(&ini, strv_init("section1"));
+    ASSERT(section1 != NULL);
+    ASSERT(strv_equals(section1->name, strv_init("section1")));
+    
+    // Test section1 values
+    inivalue_t *key1 = ini_get(section1, strv_init("key1"));
+    ASSERT(key1 != NULL);
+    ASSERT(strv_equals(key1->key, strv_init("key1")));
+    ASSERT(strv_equals(key1->value, strv_init("value1")));
+    
+    inivalue_t *key2 = ini_get(section1, strv_init("key2"));
+    ASSERT(key2 != NULL);
+    ASSERT(strv_equals(key2->key, strv_init("key2")));
+    ASSERT(strv_equals(key2->value, strv_init("value2")));
+    
+    // Test section2
+    initable_t *section2 = ini_get_table(&ini, strv_init("section2"));
+    ASSERT(section2 != NULL);
+    ASSERT(strv_equals(section2->name, strv_init("section2")));
+    
+    // Test section2 values
+    inivalue_t *key3 = ini_get(section2, strv_init("key3"));
+    ASSERT(key3 != NULL);
+    ASSERT(strv_equals(key3->key, strv_init("key3")));
+    ASSERT(strv_equals(key3->value, strv_init("value3")));
+    
+    inivalue_t *key4 = ini_get(section2, strv_init("key4"));
+    ASSERT(key4 != NULL);
+    ASSERT(strv_equals(key4->key, strv_init("key4")));
+    ASSERT(strv_equals(key4->value, strv_init("value4")));
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(ini_parse_with_options) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    strview_t ini_content = strv_init(
+        "[section1]\n"
+        "key1:value1\n"
+        "# This is a comment\n"
+        "key2:value2\n"
+        "\n"
+        "[section1]\n"  // Duplicate section
+        "key3:value3\n"
+    );
+    
+    iniopt_t options = {
+        .merge_duplicate_tables = true,
+        .merge_duplicate_keys = false,
+        .key_value_divider = ':',
+        .comment_vals = strv_init("#")
+    };
+    
+    ini_t ini = ini_parse_str(&arena, ini_content, &options);
+    ASSERT(ini_is_valid(&ini));
+    
+    // Test section1 (should be merged)
+    initable_t *section1 = ini_get_table(&ini, strv_init("section1"));
+    ASSERT(section1 != NULL);
+    
+    // Check all keys exist in merged section
+    inivalue_t *key1 = ini_get(section1, strv_init("key1"));
+    ASSERT(key1 != NULL);
+    ASSERT(strv_equals(key1->value, strv_init("value1")));
+    
+    inivalue_t *key2 = ini_get(section1, strv_init("key2"));
+    ASSERT(key2 != NULL);
+    ASSERT(strv_equals(key2->value, strv_init("value2")));
+    
+    inivalue_t *key3 = ini_get(section1, strv_init("key3"));
+    ASSERT(key3 != NULL);
+    ASSERT(strv_equals(key3->value, strv_init("value3")));
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(ini_value_conversion) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    strview_t ini_content = strv_init(
+        "[values]\n"
+        "uint=42\n"
+        "int=-42\n"
+        "float=3.14\n"
+        "bool_true=true\n"
+        "bool_false=false\n"
+        "array=item1,item2,item3\n"
+    );
+    
+    ini_t ini = ini_parse_str(&arena, ini_content, NULL);
+    initable_t *values = ini_get_table(&ini, strv_init("values"));
+    ASSERT(values != NULL);
+    
+    // Test uint conversion
+    inivalue_t *uint_val = ini_get(values, strv_init("uint"));
+    ASSERT(uint_val != NULL);
+    ASSERT(ini_as_uint(uint_val) == 42);
+    
+    // Test int conversion
+    inivalue_t *int_val = ini_get(values, strv_init("int"));
+    ASSERT(int_val != NULL);
+    ASSERT(ini_as_int(int_val) == -42);
+    
+    // Test float conversion
+    inivalue_t *float_val = ini_get(values, strv_init("float"));
+    ASSERT(float_val != NULL);
+    ASSERT(ini_as_num(float_val) > 3.13 && ini_as_num(float_val) < 3.15);
+    
+    // Test bool conversion
+    inivalue_t *bool_true = ini_get(values, strv_init("bool_true"));
+    ASSERT(bool_true != NULL);
+    ASSERT(ini_as_bool(bool_true) == true);
+    
+    inivalue_t *bool_false = ini_get(values, strv_init("bool_false"));
+    ASSERT(bool_false != NULL);
+    ASSERT(ini_as_bool(bool_false) == false);
+    
+    // Test array conversion
+    inivalue_t *array_val = ini_get(values, strv_init("array"));
+    ASSERT(array_val != NULL);
+    
+    iniarray_t array = ini_as_arr(&arena, array_val, ',');
+    ASSERT(array.count == 3);
+    ASSERT(strv_equals(array.values[0], strv_init("item1")));
+    ASSERT(strv_equals(array.values[1], strv_init("item2")));
+    ASSERT(strv_equals(array.values[2], strv_init("item3")));
+    
+    arena_cleanup(&arena);
+}
+
+// JSON Parser Tests
+UNIT_TEST(json_parse_basic) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    strview_t json_content = strv_init(
+        "{\n"
+        "  \"string\": \"value\",\n"
+        "  \"number\": 42,\n"
+        "  \"bool\": true,\n"
+        "  \"null\": null,\n"
+        "  \"array\": [1, 2, 3],\n"
+        "  \"object\": {\n"
+        "    \"nested\": \"nested_value\"\n"
+        "  }\n"
+        "}"
+    );
+    
+    json_t *root = json_parse_str(&arena, json_content, JSON_DEFAULT);
+    ASSERT(root != NULL);
+    ASSERT(root->type == JSON_OBJECT);
+    
+    // Test string
+    json_t *string_node = json_get(root, strv_init("string"));
+    ASSERT(json_check(string_node, JSON_STRING));
+    ASSERT(strv_equals(string_node->string, strv_init("value")));
+    
+    // Test number
+    json_t *number_node = json_get(root, strv_init("number"));
+    ASSERT(json_check(number_node, JSON_NUMBER));
+    ASSERT(number_node->number == 42);
+    
+    // Test bool
+    json_t *bool_node = json_get(root, strv_init("bool"));
+    ASSERT(json_check(bool_node, JSON_BOOL));
+    ASSERT(bool_node->boolean == true);
+    
+    // Test null
+    json_t *null_node = json_get(root, strv_init("null"));
+    ASSERT(json_check(null_node, JSON_NULL));
+    
+    // Test array
+    json_t *array_node = json_get(root, strv_init("array"));
+    ASSERT(json_check(array_node, JSON_ARRAY));
+    
+    // Test array contents
+    int count = 0;
+    int sum = 0;
+    json_for(item, array_node) {
+        ASSERT(json_check(item, JSON_NUMBER));
+        sum += (int)item->number;
+        count++;
+    }
+    ASSERT(count == 3);
+    ASSERT(sum == 6);  // 1 + 2 + 3
+    
+    // Test nested object
+    json_t *object_node = json_get(root, strv_init("object"));
+    ASSERT(json_check(object_node, JSON_OBJECT));
+    
+    json_t *nested_node = json_get(object_node, strv_init("nested"));
+    ASSERT(json_check(nested_node, JSON_STRING));
+    ASSERT(strv_equals(nested_node->string, strv_init("nested_value")));
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(json_parse_with_options) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    // JSON with comments and trailing commas
+    strview_t json_content = strv_init(
+        "{\n"
+        "  \"key1\": \"value1\",\n"
+        "  // This is a comment\n"
+        "  \"key2\": \"value2\",\n"
+        "  \"array\": [\n"
+        "    1,\n"
+        "    2,\n"
+        "    3,\n"  // Trailing comma
+        "  ],\n"  // Trailing comma
+        "}"
+    );
+    
+    // Test with default flags (should allow comments and trailing commas)
+    json_t *root1 = json_parse_str(&arena, json_content, JSON_DEFAULT);
+    ASSERT(root1 != NULL);
+    ASSERT(json_get(root1, strv_init("key1")) != NULL);
+    ASSERT(json_get(root1, strv_init("key2")) != NULL);
+    
+    // Test with NO_COMMENTS and NO_TRAILING_COMMAS flags
+    json_t *root2 = json_parse_str(&arena, json_content, JSON_NO_COMMENTS | JSON_NO_TRAILING_COMMAS);
+    
+    // This should fail parsing due to the strict flags - but the behavior depends on implementation
+    // Some parsers might ignore the errors, others might return NULL
+    // We'll check both possibilities
+    if (root2 != NULL) {
+        // If parsing succeeded despite strict flags, ensure the content is correct
+        ASSERT(json_get(root2, strv_init("key1")) != NULL);
+        // key2 might be missing if comment handling failed
+    }
+    
+    arena_cleanup(&arena);
+}
+
+// XML Parser Tests
+UNIT_TEST(xml_parse_basic) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    strview_t xml_content = strv_init(
+        "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+        "<root>\n"
+        "  <item id=\"1\" type=\"book\">\n"
+        "    <title>Test Title</title>\n"
+        "    <author>Test Author</author>\n"
+        "  </item>\n"
+        "  <item id=\"2\" type=\"magazine\">\n"
+        "    <title>Another Title</title>\n"
+        "  </item>\n"
+        "</root>"
+    );
+    
+    xml_t xml = xml_parse_str(&arena, xml_content);
+    ASSERT(xml.root != NULL);
+    ASSERT(strv_equals(xml.root->key, strv_init("root")));
+    
+    // Find item tags
+    xmltag_t *item = xml_get_tag(xml.root, strv_init("item"), false);
+    ASSERT(item != NULL);
+    
+    // Check attributes
+    strview_t id = xml_get_attribute(item, strv_init("id"));
+    ASSERT(strv_equals(id, strv_init("1")));
+    
+    strview_t type = xml_get_attribute(item, strv_init("type"));
+    ASSERT(strv_equals(type, strv_init("book")));
+    
+    // Check nested tags
+    xmltag_t *title = xml_get_tag(item, strv_init("title"), false);
+    ASSERT(title != NULL);
+    ASSERT(strv_equals(title->content, strv_init("Test Title")));
+    
+    xmltag_t *author = xml_get_tag(item, strv_init("author"), false);
+    ASSERT(author != NULL);
+    ASSERT(strv_equals(author->content, strv_init("Test Author")));
+    
+    // Check recursive tag finding
+    xmltag_t *title_recursive = xml_get_tag(xml.root, strv_init("title"), true);
+    ASSERT(title_recursive != NULL);
+    ASSERT(strv_equals(title_recursive->content, strv_init("Test Title")));
+    
+    arena_cleanup(&arena);
+}
+
+// HTML Parser Tests
+UNIT_TEST(html_parse_basic) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    strview_t html_content = strv_init(
+        "<!DOCTYPE html>\n"
+        "<html>\n"
+        "<head>\n"
+        "  <title>Test Page</title>\n"
+        "</head>\n"
+        "<body>\n"
+        "  <h1>Hello World</h1>\n"
+        "  <p class=\"intro\">This is a test.</p>\n"
+        "  <div id=\"content\">\n"
+        "    <p>More content here.</p>\n"
+        "  </div>\n"
+        "</body>\n"
+        "</html>"
+    );
+    
+    html_t html = html_parse_str(&arena, html_content);
+    ASSERT(html.root != NULL);
+    ASSERT(str_equals(html.root->key, str_init(&arena, "html")));
+    
+    // Find head and body
+    htmltag_t *head = html_get_tag(html.root, strv_init("head"), false);
+    ASSERT(head != NULL);
+    
+    htmltag_t *body = html_get_tag(html.root, strv_init("body"), false);
+    ASSERT(body != NULL);
+    
+    // Find title in head
+    htmltag_t *title = html_get_tag(head, strv_init("title"), false);
+    ASSERT(title != NULL);
+    ASSERT(strv_equals(title->content, strv_init("Test Page")));
+    
+    // Find elements in body
+    htmltag_t *h1 = html_get_tag(body, strv_init("h1"), false);
+    ASSERT(h1 != NULL);
+    ASSERT(strv_equals(h1->content, strv_init("Hello World")));
+    
+    // Find paragraph with class
+    htmltag_t *p = html_get_tag(body, strv_init("p"), false);
+    ASSERT(p != NULL);
+    
+    strview_t p_class = html_get_attribute(p, strv_init("class"));
+    ASSERT(strv_equals(p_class, strv_init("intro")));
+    ASSERT(strv_equals(p->content, strv_init("This is a test.")));
+    
+    // Find div by id
+    htmltag_t *div = html_get_tag(body, strv_init("div"), false);
+    ASSERT(div != NULL);
+    
+    strview_t div_id = html_get_attribute(div, strv_init("id"));
+    ASSERT(strv_equals(div_id, strv_init("content")));
+    
+    // Find nested paragraph using recursive search
+    htmltag_t *nested_p = html_get_tag(div, strv_init("p"), false);
+    ASSERT(nested_p != NULL);
+    ASSERT(strv_equals(nested_p->content, strv_init("More content here.")));
+    
+    arena_cleanup(&arena);
+}
diff --git a/tests/pretty_print_tests.c b/tests/pretty_print_tests.c
new file mode 100644
index 0000000..754bb1f
--- /dev/null
+++ b/tests/pretty_print_tests.c
@@ -0,0 +1,34 @@
+#include "runner.h"
+#include "../pretty_print.h"
+#include "../arena.h"
+#include <stdio.h>
+
+UNIT_TEST(pretty_print_basic) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    // The pretty_print function outputs to console, so we can't easily verify its exact output
+    // Instead, we'll just verify it doesn't crash
+    pretty_print(arena, "Hello, <red>World!</>");
+    
+    // Test with formatting
+    pretty_print(arena, "Value: <blue>%d</>, String: <green>%s</>", 42, "test");
+    
+    arena_cleanup(&arena);
+}
+
+// Helper function to test variadic function
+void test_pretty_printv(arena_t arena, const char *fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    pretty_printv(arena, fmt, args);
+    va_end(args);
+}
+
+UNIT_TEST(pretty_printv) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+   
+    // Test the helper function
+    test_pretty_printv(arena, "Test <yellow>%d</> <cyan>%s</>", 42, "variadic");
+    
+    arena_cleanup(&arena);
+}
diff --git a/tests/runner.h b/tests/runner.h
new file mode 100644
index 0000000..55085c5
--- /dev/null
+++ b/tests/runner.h
@@ -0,0 +1,41 @@
+#pragma once
+
+#include "../core.h"
+#include "../str.h"
+
+typedef struct unit_test_t unit_test_t;
+struct unit_test_t {
+    strview_t fname;
+    strview_t name;
+    void (*fn)(void);
+    unit_test_t *next;
+};
+
+extern unit_test_t *test_head;
+extern unit_test_t *test_tail;
+extern const char *last_fail_reason;
+extern bool last_failed;
+
+void ut_register(const char *file, const char *name, void (*fn)(void));
+
+// #pragma data_seg(".CRT$XCU")
+
+#define INITIALIZER(f) \
+    static void f(void); \
+    __declspec(allocate(".CRT$XCU")) void (*f##_)(void) = f; \
+    __pragma(comment(linker,"/include:" #f "_")) \
+    static void f(void)
+
+#define UNIT_TEST(name) \
+    void ut__test_##name(void); \
+    INITIALIZER(ut__register_##name) { ut_register(__FILE__, #name, ut__test_##name); } \
+    void ut__test_##name(void)
+    
+
+#define ASSERT(cond) \
+    if (!(cond)) { \
+        last_fail_reason = "assert(" COLLA_STRINGIFY(cond) ") at " COLLA_STRINGIFY(__LINE__); \
+        last_failed = true; \
+        return; \
+    }
+
diff --git a/tests/str_tests.c b/tests/str_tests.c
new file mode 100644
index 0000000..0e90b7c
--- /dev/null
+++ b/tests/str_tests.c
@@ -0,0 +1,457 @@
+#include "runner.h"
+#include "../str.h"
+#include "../arena.h"
+#include <stdio.h>
+
+// String (str_t) Tests
+UNIT_TEST(str_init_basic) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    str_t s = str_init(&arena, "hello");
+    
+    ASSERT(s.len == 5);
+    ASSERT(s.buf != NULL);
+    ASSERT(memcmp(s.buf, "hello", 5) == 0);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(str_init_len) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    str_t s = str_init_len(&arena, "hello world", 5);
+    
+    ASSERT(s.len == 5);
+    ASSERT(s.buf != NULL);
+    ASSERT(memcmp(s.buf, "hello", 5) == 0);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(str_fmt) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    str_t s = str_fmt(&arena, "Number: %d, String: %s", 42, "test");
+    
+    ASSERT(s.buf != NULL);
+    ASSERT(memcmp(s.buf, "Number: 42, String: test", s.len) == 0);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(str_equals) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    str_t s1 = str_init(&arena, "hello");
+    str_t s2 = str_init(&arena, "hello");
+    str_t s3 = str_init(&arena, "world");
+    
+    ASSERT(str_equals(s1, s2) == true);
+    ASSERT(str_equals(s1, s3) == false);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(str_compare) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    str_t s1 = str_init(&arena, "abc");
+    str_t s2 = str_init(&arena, "abc");
+    str_t s3 = str_init(&arena, "abd");
+    str_t s4 = str_init(&arena, "abb");
+    
+    ASSERT(str_compare(s1, s2) == 0);
+    ASSERT(str_compare(s1, s3) < 0);
+    ASSERT(str_compare(s1, s4) > 0);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(str_dup) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    str_t s1 = str_init(&arena, "test");
+    str_t s2 = str_dup(&arena, s1);
+    
+    ASSERT(s1.len == s2.len);
+    ASSERT(s1.buf != s2.buf); // Different memory locations
+    ASSERT(memcmp(s1.buf, s2.buf, s1.len) == 0);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(str_cat) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    str_t s1 = str_init(&arena, "hello ");
+    str_t s2 = str_init(&arena, "world");
+    str_t s3 = str_cat(&arena, s1, s2);
+    
+    ASSERT(s3.len == s1.len + s2.len);
+    ASSERT(memcmp(s3.buf, "hello world", s3.len) == 0);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(str_is_empty) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    str_t s1 = str_init(&arena, "test");
+    str_t s2 = STR_EMPTY;
+    
+    ASSERT(str_is_empty(s1) == false);
+    ASSERT(str_is_empty(s2) == true);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(str_lower_upper) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    str_t s1 = str_init(&arena, "TeSt");
+    str_lower(&s1);
+    ASSERT(memcmp(s1.buf, "test", 4) == 0);
+    
+    str_t s2 = str_init(&arena, "TeSt");
+    str_upper(&s2);
+    ASSERT(memcmp(s2.buf, "TEST", 4) == 0);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(str_replace) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    str_t s = str_init(&arena, "hello");
+    str_replace(&s, 'l', 'x');
+    ASSERT(memcmp(s.buf, "hexxo", 5) == 0);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(str_sub) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    str_t s = str_init(&arena, "hello world");
+    strview_t sv = str_sub(s, 6, 11);
+    
+    ASSERT(sv.len == 5);
+    ASSERT(memcmp(sv.buf, "world", 5) == 0);
+    
+    arena_cleanup(&arena);
+}
+
+// String View (strview_t) Tests
+UNIT_TEST(strv_init) {
+    strview_t sv = strv_init("hello");
+    
+    ASSERT(sv.len == 5);
+    ASSERT(sv.buf != NULL);
+    ASSERT(memcmp(sv.buf, "hello", 5) == 0);
+}
+
+UNIT_TEST(strv_init_len) {
+    strview_t sv = strv_init_len("hello world", 5);
+    
+    ASSERT(sv.len == 5);
+    ASSERT(sv.buf != NULL);
+    ASSERT(memcmp(sv.buf, "hello", 5) == 0);
+}
+
+UNIT_TEST(strv_init_str) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    
+    str_t s = str_init(&arena, "hello");
+    strview_t sv = strv_init_str(s);
+    
+    ASSERT(sv.len == s.len);
+    ASSERT(sv.buf == s.buf);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(strv_is_empty) {
+    strview_t sv1 = strv_init("test");
+    strview_t sv2 = STRV_EMPTY;
+    
+    ASSERT(strv_is_empty(sv1) == false);
+    ASSERT(strv_is_empty(sv2) == true);
+}
+
+UNIT_TEST(strv_equals) {
+    strview_t sv1 = strv_init("hello");
+    strview_t sv2 = strv_init("hello");
+    strview_t sv3 = strv_init("world");
+    
+    ASSERT(strv_equals(sv1, sv2) == true);
+    ASSERT(strv_equals(sv1, sv3) == false);
+}
+
+UNIT_TEST(strv_compare) {
+    strview_t sv1 = strv_init("abc");
+    strview_t sv2 = strv_init("abc");
+    strview_t sv3 = strv_init("abd");
+    strview_t sv4 = strv_init("abb");
+    
+    ASSERT(strv_compare(sv1, sv2) == 0);
+    ASSERT(strv_compare(sv1, sv3) < 0);
+    ASSERT(strv_compare(sv1, sv4) > 0);
+}
+
+UNIT_TEST(strv_front_back) {
+    strview_t sv = strv_init("hello");
+    
+    ASSERT(strv_front(sv) == 'h');
+    ASSERT(strv_back(sv) == 'o');
+}
+
+UNIT_TEST(strv_remove_prefix_suffix) {
+    strview_t sv = strv_init("hello");
+    
+    strview_t prefix_removed = strv_remove_prefix(sv, 2);
+    ASSERT(prefix_removed.len == 3);
+    ASSERT(memcmp(prefix_removed.buf, "llo", 3) == 0);
+    
+    strview_t suffix_removed = strv_remove_suffix(sv, 2);
+    ASSERT(suffix_removed.len == 3);
+    ASSERT(memcmp(suffix_removed.buf, "hel", 3) == 0);
+}
+
+UNIT_TEST(strv_trim) {
+    strview_t sv1 = strv_init("  hello  ");
+    strview_t sv2 = strv_init("  hello");
+    strview_t sv3 = strv_init("hello  ");
+    
+    strview_t trimmed1 = strv_trim(sv1);
+    strview_t trimmed2 = strv_trim_left(sv2);
+    strview_t trimmed3 = strv_trim_right(sv3);
+    
+    ASSERT(trimmed1.len == 5);
+    ASSERT(memcmp(trimmed1.buf, "hello", 5) == 0);
+    
+    ASSERT(trimmed2.len == 5);
+    ASSERT(memcmp(trimmed2.buf, "hello", 5) == 0);
+    
+    ASSERT(trimmed3.len == 5);
+    ASSERT(memcmp(trimmed3.buf, "hello", 5) == 0);
+}
+
+UNIT_TEST(strv_sub) {
+    strview_t sv = strv_init("hello world");
+    strview_t sub = strv_sub(sv, 6, 11);
+    
+    ASSERT(sub.len == 5);
+    ASSERT(memcmp(sub.buf, "world", 5) == 0);
+}
+
+UNIT_TEST(strv_starts_ends_with) {
+    strview_t sv = strv_init("hello");
+    
+    ASSERT(strv_starts_with(sv, 'h') == true);
+    ASSERT(strv_starts_with(sv, 'e') == false);
+    
+    ASSERT(strv_ends_with(sv, 'o') == true);
+    ASSERT(strv_ends_with(sv, 'l') == false);
+    
+    strview_t prefix = strv_init("hel");
+    strview_t suffix = strv_init("llo");
+    
+    ASSERT(strv_starts_with_view(sv, prefix) == true);
+    ASSERT(strv_ends_with_view(sv, suffix) == true);
+}
+
+UNIT_TEST(strv_contains) {
+    strview_t sv = strv_init("hello world");
+    
+    ASSERT(strv_contains(sv, 'e') == true);
+    ASSERT(strv_contains(sv, 'z') == false);
+    
+    strview_t sub = strv_init("world");
+    ASSERT(strv_contains_view(sv, sub) == true);
+    
+    strview_t chars = strv_init("xyz");
+    ASSERT(strv_contains_either(sv, chars) == false);
+    
+    strview_t chars2 = strv_init("xyo");
+    ASSERT(strv_contains_either(sv, chars2) == true);
+}
+
+UNIT_TEST(strv_find) {
+    strview_t sv = strv_init("hello world");
+    
+    ASSERT(strv_find(sv, 'o', 0) == 4);
+    ASSERT(strv_find(sv, 'o', 5) == 7);
+    ASSERT(strv_find(sv, 'z', 0) == STR_NONE);
+    
+    strview_t sub = strv_init("world");
+    ASSERT(strv_find_view(sv, sub, 0) == 6);
+    
+    strview_t chars = strv_init("xwo");
+    ASSERT(strv_find_either(sv, chars, 0) == 4); // 'w' at position 6
+}
+
+UNIT_TEST(strv_rfind) {
+    strview_t sv = strv_init("hello world");
+    
+    ASSERT(strv_rfind(sv, 'o', 0) == 7);
+    ASSERT(strv_rfind(sv, 'o', 5) == 4);
+    ASSERT(strv_rfind(sv, 'z', 0) == STR_NONE);
+    
+    strview_t sub = strv_init("world");
+    ASSERT(strv_rfind_view(sv, sub, 0) == 6);
+}
+
+// Character Functions Tests
+UNIT_TEST(char_functions) {
+    ASSERT(char_is_space(' ') == true);
+    ASSERT(char_is_space('\t') == true);
+    ASSERT(char_is_space('a') == false);
+    
+    ASSERT(char_is_alpha('a') == true);
+    ASSERT(char_is_alpha('Z') == true);
+    ASSERT(char_is_alpha('1') == false);
+    
+    ASSERT(char_is_num('0') == true);
+    ASSERT(char_is_num('9') == true);
+    ASSERT(char_is_num('a') == false);
+    
+    ASSERT(char_lower('A') == 'a');
+    ASSERT(char_lower('a') == 'a');
+    ASSERT(char_lower('1') == '1');
+}
+
+// Input Stream Tests
+UNIT_TEST(instream_basic) {
+    strview_t sv = strv_init("hello world");
+    instream_t is = istr_init(sv);
+    
+    ASSERT(istr_get(&is) == 'h');
+    ASSERT(istr_get(&is) == 'e');
+    ASSERT(istr_peek(&is) == 'l');
+    ASSERT(istr_peek_next(&is) == 'l');
+    ASSERT(istr_get(&is) == 'l');
+    ASSERT(istr_prev(&is) == 'l');
+    ASSERT(istr_prev_prev(&is) == 'e');
+    
+    istr_skip(&is, 2);
+    ASSERT(istr_peek(&is) == ' ');
+    
+    istr_skip_whitespace(&is);
+    ASSERT(istr_peek(&is) == 'w');
+    
+    istr_rewind(&is);
+    ASSERT(istr_peek(&is) == 'h');
+    
+    ASSERT(istr_tell(&is) == 0);
+    ASSERT(istr_remaining(&is) == 11);
+    ASSERT(istr_is_finished(&is) == false);
+}
+
+UNIT_TEST(instream_ignore) {
+    strview_t sv = strv_init("hello,world");
+    instream_t is = istr_init(sv);
+    
+    istr_ignore(&is, ',');
+    ASSERT(istr_peek(&is) == ',');
+    
+    istr_ignore_and_skip(&is, ',');
+    ASSERT(istr_peek(&is) == 'w');
+}
+
+UNIT_TEST(instream_get_values) {
+    strview_t sv = strv_init("true 42 3.14 hello");
+    instream_t is = istr_init(sv);
+    
+    bool b;
+    ASSERT(istr_get_bool(&is, &b) == true);
+    ASSERT(b == true);
+    
+    istr_skip_whitespace(&is);
+    
+    u32 u;
+    ASSERT(istr_get_u32(&is, &u) == true);
+    ASSERT(u == 42);
+    
+    istr_skip_whitespace(&is);
+    
+    double d;
+    ASSERT(istr_get_num(&is, &d) == true);
+    ASSERT(d > 3.13 && d < 3.15);
+    
+    istr_skip_whitespace(&is);
+    
+    strview_t word = istr_get_view(&is, ' ');
+    ASSERT(word.len == 5);
+    ASSERT(memcmp(word.buf, "hello", 5) == 0);
+}
+
+// Output Stream Tests
+UNIT_TEST(outstream_basic) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    outstream_t os = ostr_init(&arena);
+    
+    ostr_putc(&os, 'h');
+    ostr_putc(&os, 'i');
+    
+    ASSERT(ostr_tell(&os) == 2);
+    ASSERT(ostr_back(&os) == 'i');
+    
+    ostr_print(&os, " %d", 42);
+    
+    strview_t result = ostr_as_view(&os);
+    ASSERT(result.len == 5);
+    ASSERT(memcmp(result.buf, "hi 42", 5) == 0);
+    
+    ostr_pop(&os, 3);
+    result = ostr_as_view(&os);
+    ASSERT(result.len == 2);
+    ASSERT(memcmp(result.buf, "hi", 2) == 0);
+    
+    ostr_clear(&os);
+    ASSERT(ostr_tell(&os) == 0);
+    
+    arena_cleanup(&arena);
+}
+
+UNIT_TEST(outstream_append) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(4));
+    outstream_t os = ostr_init(&arena);
+    
+    ostr_append_bool(&os, true);
+    ostr_putc(&os, ' ');
+    ostr_append_uint(&os, 42);
+    ostr_putc(&os, ' ');
+    ostr_append_int(&os, -10);
+    ostr_putc(&os, ' ');
+    ostr_append_num(&os, 3.14);
+    
+    str_t result = ostr_to_str(&os);
+    ASSERT(result.len > 0);
+    
+    arena_cleanup(&arena);
+}
+
+// Binary Input Stream Tests
+UNIT_TEST(binary_stream) {
+    u8 data[] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08};
+    buffer_t buffer = {data, sizeof(data)};
+    
+    ibstream_t bs = ibstr_init(buffer);
+    
+    ASSERT(ibstr_remaining(&bs) == 8);
+    ASSERT(ibstr_tell(&bs) == 0);
+    ASSERT(ibstr_is_finished(&bs) == false);
+    
+    u8 val8;
+    ASSERT(ibstr_get_u8(&bs, &val8) == true);
+    ASSERT(val8 == 0x01);
+    
+    u16 val16;
+    ASSERT(ibstr_get_u16(&bs, &val16) == true);
+    ASSERT(val16 == 0x0302); // Assuming little-endian
+    
+    ibstr_skip(&bs, 1);
+    
+    u32 val32;
+    ASSERT(ibstr_get_u32(&bs, &val32) == true);
+    ASSERT(val32 == 0x08070605); // Assuming little-endian
+    
+    ASSERT(ibstr_is_finished(&bs) == true);
+}
diff --git a/tests/string_tests.c b/tests/string_tests.c
new file mode 100644
index 0000000..ffc204b
--- /dev/null
+++ b/tests/string_tests.c
@@ -0,0 +1,12 @@
+#include "runner.h"
+#include "../str.h"
+#include "../arena.h"
+
+UNIT_TEST(str_format) {
+    arena_t arena = arena_make(ARENA_MALLOC, KB(1));
+    str_t s = str_fmt(&arena, "%d %s", 42, "test");
+    str_t lit = str(&arena, "42 test");
+    ASSERT(str_equals(s, lit));
+    arena_cleanup(&arena);
+}
+
diff --git a/tools/nob.c b/tools/nob.c
index 090beb7..834bf61 100644
--- a/tools/nob.c
+++ b/tools/nob.c
@@ -1,4 +1,5 @@
 #define COLLA_NO_CONDITION_VARIABLE 1
+#define COLLA_NO_NET 1
 
 #include "../build.c"
 #include <windows.h>
@@ -296,7 +297,7 @@ int main(int argc, char **argv) {
 
     options_t opt = parse_options(&arena, argc, argv);
 
-    if (!os_file_exists(strv("build/"))) {
+    if (!os_dir_exists(strv("build/"))) {
         info("creating build folder");
         _mkdir("build");
     }
@@ -307,7 +308,14 @@ int main(int argc, char **argv) {
         arena_t scratch = arena;
         str_t vcvars_path = find_vcvars_path(&scratch);
 
-        if (!os_run_cmd(scratch, os_make_cmd(strv(vcvars_path), strv("&&"), strv("set"), strv(">"), strv("build\\cache.ini")), NULL)) {
+        os_cmd_t *cmd = NULL;
+        darr_push(&scratch, cmd, strv(vcvars_path));
+        darr_push(&scratch, cmd, strv("&&"));
+        darr_push(&scratch, cmd, strv("set"));
+        darr_push(&scratch, cmd, strv(">"));
+        darr_push(&scratch, cmd, strv("build\\cache.ini"));
+
+        if (!os_run_cmd(scratch, cmd, NULL)) { 
             fatal("failed to run vcvars64.bat");
             os_abort(1);
         }
@@ -366,6 +374,7 @@ int main(int argc, char **argv) {
 
         if (opt.debug) {
             darr_push(&scratch, cmd, strv("/Zi"));
+            darr_push(&scratch, cmd, strv("/D_DEBUG"));
         }
 
         for_each (def, opt.defines) {
@@ -415,4 +424,4 @@ int main(int argc, char **argv) {
     arena_cleanup(&arena);
 
     os_cleanup();
-}
\ No newline at end of file
+}
diff --git a/tools/unit_tests.c b/tools/unit_tests.c
new file mode 100644
index 0000000..0f5f0ab
--- /dev/null
+++ b/tools/unit_tests.c
@@ -0,0 +1,80 @@
+#pragma section(".CRT$XCU", read)
+
+#include "../build.c"
+#include "../tests/runner.h"
+
+#include "../tests/arena_tests.c"
+#include "../tests/core_tests.c"
+#include "../tests/net_tests.c"
+#include "../tests/os_tests.c"
+// #include "../tests/parsers_tests.c"
+// #include "../tests/pretty_print_tests.c"
+#include "../tests/str_tests.c"
+
+unit_test_t *test_head = NULL;
+unit_test_t *test_tail = NULL;
+const char *last_fail_reason = NULL;
+bool last_failed = false;
+
+void ut_register(const char *file, const char *name, void (*fn)(void)) {
+    strview_t fname;
+    os_file_split_path(strv(file), NULL, &fname, NULL);
+
+    fname = strv_remove_suffix(fname, arrlen("_tests") - 1);
+
+    unit_test_t *test = calloc(1, sizeof(unit_test_t));
+    test->name = strv(name);
+    test->fn = fn;
+    test->fname = fname;
+
+    olist_push(test_head, test_tail, test);
+}
+
+int main() {
+    colla_init(COLLA_ALL);
+    arena_t arena = arena_make(ARENA_VIRTUAL, GB(1));
+
+    strview_t last_file = STRV_EMPTY;
+    int success = 0;
+    int failed = 0;
+    int total = 0;
+
+    unit_test_t *test = test_head;
+    while (test) {
+        if (!strv_equals(test->fname, last_file)) {
+            last_file = test->fname;
+            pretty_print(arena, "<blue>> %v</>\n", test->fname);
+        }
+
+        test->fn();
+
+        total++;
+
+        if (last_failed) {
+            pretty_print(arena, "%4s<red>[X]</> %v: %s\n", "", test->name, last_fail_reason);
+        }
+        else {
+            pretty_print(arena, "%4s<green>[V]</> %v\n", "", test->name);
+            success++;
+        }
+
+        last_failed = false;
+
+        test = test->next;
+    }
+
+    print("\n");
+
+    strview_t colors[] = { 
+        cstrv("red"), 
+        cstrv("light_red"), 
+        cstrv("yellow"), 
+        cstrv("light_yellow"), 
+        cstrv("light_green"), 
+        cstrv("green"), 
+    };
+
+    usize col = success * (arrlen(colors) - 1) / total;
+
+    pretty_print(arena, "<%v>%d</>/<blue>%d</> tests passed\n", colors[col], success, total);
+}
diff --git a/win/net_win32.c b/win/net_win32.c
index f209ba9..b844eb7 100644
--- a/win/net_win32.c
+++ b/win/net_win32.c
@@ -48,6 +48,10 @@ iptr net_get_last_error(void) {
 }
 
 http_res_t http_request(http_request_desc_t *req) {
+    return http_request_cb(req, NULL, NULL);
+}
+
+http_res_t http_request_cb(http_request_desc_t *req, http_request_callback_fn callback, void *userdata) {
     HINTERNET connection = NULL;
     HINTERNET request = NULL;
     BOOL result = FALSE;
@@ -135,7 +139,14 @@ http_res_t http_request(http_request_desc_t *req) {
         (DWORD)req->body.len
     );
     if (!result) {
-        err("call to HttpSendRequest failed: %v", os_get_error_string(os_get_last_error()));
+        iptr error = os_get_last_error();
+        if (error == ERROR_INTERNET_NAME_NOT_RESOLVED) {
+            err("invalid url: %v", req->url);
+        }
+        else {
+            err("call to HttpSendRequest failed: %lld", error);
+            // os_get_error_string(error));
+        }
         goto failed;
     }
 
@@ -186,7 +197,12 @@ http_res_t http_request(http_request_desc_t *req) {
         if (!read_success || read == 0) {
             break;
         }
-        ostr_puts(&body, strv(read_buffer, read));
+    
+        strview_t chunk = strv(read_buffer, read);
+        if (callback) {
+            callback(chunk, userdata);
+        }
+        ostr_puts(&body, chunk);
     }
 
     res.body = strv(ostr_to_str(&body));
diff --git a/win/os_win32.c b/win/os_win32.c
index 9f17762..3317edf 100644
--- a/win/os_win32.c
+++ b/win/os_win32.c
@@ -1,6 +1,10 @@
 #include <windows.h>
 #include <assert.h>
 
+#if COLLA_DEBUG
+#include <stdlib.h> // abort
+#endif
+
 #include "../os.h"
 #include "../net.h"
 
@@ -37,6 +41,8 @@ struct {
     os_entity_t *entity_free;
     oshandle_t hstdout;
     oshandle_t hstdin;
+    WORD default_fg;
+    WORD default_bg;
 } w32_data = {0};
 
 os_entity_t *os__win_alloc_entity(os_entity_kind_e kind) {
@@ -77,14 +83,23 @@ void os_init(void) {
 
     info->machine_name = str_from_tstr(&w32_data.arena, (tstr_t){ namebuf, namebuflen});
 
-    HANDLE hstdout = CreateFile(TEXT("CONOUT$"), GENERIC_WRITE, FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
-    HANDLE hstdin = CreateFile(TEXT("CONIN$"), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
+    HANDLE hstdout = CreateFile(TEXT("CONOUT$"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
+    HANDLE hstdin = CreateFile(TEXT("CONIN$"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
 
     if (hstdout == INVALID_HANDLE_VALUE) err("couldn't open CONOUT$");
     else w32_data.hstdout.data = (uptr)hstdout;
 
     if (hstdin == INVALID_HANDLE_VALUE) err("couldn't open CONIN$");
     else w32_data.hstdin.data = (uptr)hstdin;
+
+    CONSOLE_SCREEN_BUFFER_INFO console_info = {0};
+    if (GetConsoleScreenBufferInfo(hstdout, &console_info)) {
+        w32_data.default_fg = console_info.wAttributes & 0x0F;
+        w32_data.default_bg = (console_info.wAttributes & 0xF0) >> 4;
+    }
+    else {
+        err("couldn't get console screen buffer info: %v", os_get_error_string(os_get_last_error()));
+    }
 }
 
 void os_cleanup(void) {
@@ -95,6 +110,9 @@ void os_cleanup(void) {
 }
 
 void os_abort(int code) {
+#if COLLA_DEBUG
+    if (code != 0) abort();
+#endif
     ExitProcess(code);
 }
 
@@ -111,19 +129,21 @@ str_t os_get_error_string(iptr error) {
     DWORD chars;
     chars = FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, code, 0, msgbuf, arrlen(msgbuf), NULL);
     if (chars == 0) {
-        err("FormatMessageW: %ld", os_get_last_error());
+        iptr fmt_error = os_get_last_error();
+        if (fmt_error == ERROR_MR_MID_NOT_FOUND) {
+            return str_fmt(&arena, "(unknown error: 0x%04x)", fmt_error);
+        }
+        err("FormatMessageW: %ld", fmt_error);
         return STR_EMPTY;
     }
 
-    debug("error: %zi 0x%zX", error, error);
-
     // remove \r\n at the end
     return str_from_str16(&arena, str16_init(msgbuf, chars - 2));
 }
 
 os_wait_t os_wait_on_handles(oshandle_t *handles, int count, bool wait_all, u32 milliseconds) {
     HANDLE win_handles[OS_MAX_WAITABLE_HANDLES] = {0};
-    assert(count < MAXIMUM_WAIT_OBJECTS);
+    colla_assert(count < MAXIMUM_WAIT_OBJECTS);
 
     for (int i = 0; i < count; ++i) {
         win_handles[i] = (HANDLE)(handles[i].data);
@@ -156,20 +176,16 @@ os_system_info_t os_get_system_info(void) {
 }
 
 void os_log_set_colour(os_log_colour_e colour) {
-    WORD attribute = FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE;
-    switch (colour) {
-        case LOG_COL_BLACK:   attribute = 0;                                   break;
-        case LOG_COL_RED:     attribute = FOREGROUND_RED;                      break;
-        case LOG_COL_GREEN:   attribute = FOREGROUND_GREEN;                    break;
-        case LOG_COL_BLUE:    attribute = FOREGROUND_BLUE;                     break;
-        case LOG_COL_MAGENTA: attribute = FOREGROUND_RED   | FOREGROUND_BLUE;  break;
-        case LOG_COL_YELLOW:  attribute = FOREGROUND_RED   | FOREGROUND_GREEN; break;
-        case LOG_COL_CYAN:    attribute = FOREGROUND_GREEN | FOREGROUND_BLUE;  break;
-        default: break;
-    }
+    WORD attribute = colour == LOG_COL_RESET ? w32_data.default_fg : (WORD)colour;
+    SetConsoleTextAttribute((HANDLE)w32_data.hstdout.data, attribute);
+}
 
-    HANDLE hc = GetStdHandle(STD_OUTPUT_HANDLE);
-    SetConsoleTextAttribute(hc, attribute | FOREGROUND_INTENSITY);
+void os_log_set_colour_bg(os_log_colour_e foreground, os_log_colour_e background) {
+    WORD fg_attr = foreground == LOG_COL_RESET ? w32_data.default_fg : (WORD)foreground;
+    WORD bg_attr = (background == LOG_COL_RESET ? w32_data.default_bg : (WORD)background) << 4;
+
+    WORD attribute = fg_attr | bg_attr;
+    SetConsoleTextAttribute((HANDLE)w32_data.hstdout.data, attribute);
 }
 
 oshandle_t os_stdout(void) {
@@ -206,6 +222,26 @@ bool os_file_exists(strview_t path) {
     return attributes != INVALID_FILE_ATTRIBUTES && !(attributes & FILE_ATTRIBUTE_DIRECTORY);
 }
 
+bool os_dir_exists(strview_t folder) {
+    OS_SMALL_SCRATCH();
+    tstr_t name = strv_to_tstr(&scratch, folder);
+    DWORD attributes = GetFileAttributes(name.buf);
+    return attributes != INVALID_FILE_ATTRIBUTES && attributes & FILE_ATTRIBUTE_DIRECTORY;
+}
+
+bool os_file_or_dir_exists(strview_t path) {
+    OS_SMALL_SCRATCH();
+    tstr_t name = strv_to_tstr(&scratch, path);
+    DWORD attributes = GetFileAttributes(name.buf);
+    return attributes != INVALID_FILE_ATTRIBUTES;
+}
+
+bool os_dir_create(strview_t folder) {
+    OS_SMALL_SCRATCH();
+    tstr_t name = strv_to_tstr(&scratch, folder);
+    return CreateDirectory(name.buf, NULL);
+}
+
 tstr_t os_file_fullpath(arena_t *arena, strview_t filename) {
     OS_SMALL_SCRATCH();
 
@@ -232,6 +268,12 @@ bool os_file_delete(strview_t path) {
     return DeleteFile(fname.buf);
 }
 
+bool os_dir_delete(strview_t path) {
+    OS_SMALL_SCRATCH();
+    tstr_t fname = strv_to_tstr(&scratch, path);
+    return RemoveDirectory(fname.buf);
+}
+
 oshandle_t os_file_open(strview_t path, filemode_e mode) {
     OS_SMALL_SCRATCH();
 
@@ -364,9 +406,15 @@ dir_entry_t os__dir_entry_from_find_data(arena_t *arena, WIN32_FIND_DATA *fd) {
 }
 
 dir_t *os_dir_open(arena_t *arena, strview_t path) {
+    usize prev = arena_tell(arena);
+    dir_t* ctx = alloc(arena, dir_t);
+
+    arena_t scratch = *arena;
+#if 0
     u8 tmpbuf[KB(1)] = {0};
     arena_t scratch = arena_make(ARENA_STATIC, sizeof(tmpbuf), tmpbuf);
-    
+#endif
+
     tstr_t winpath = strv_to_tstr(&scratch, path);
     // get a little extra leeway
     TCHAR fullpath[MAX_PATH + 16] = {0};
@@ -378,11 +426,10 @@ dir_t *os_dir_open(arena_t *arena, strview_t path) {
     fullpath[pathlen++] = '*';
     fullpath[pathlen++] = '\0';
 
-    dir_t *ctx = alloc(arena, dir_t);
     ctx->handle = FindFirstFile(fullpath, &ctx->find_data);
 
     if (ctx->handle == INVALID_HANDLE_VALUE) {
-        arena_pop(arena, sizeof(dir_t));
+        arena_rewind(arena, prev);
         return NULL;
     }
 
@@ -551,8 +598,15 @@ bool os_process_wait(oshandle_t proc, uint time, int *out_exit) {
     return exit_status == 0;
 }
 
+// == MEMORY ====================================
 
-// == VMEM ======================================
+void *os_alloc(usize size) {
+    return VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
+}
+
+void os_free(void *ptr) {
+    VirtualFree(ptr, 0, MEM_RELEASE);
+}
 
 void *os_reserve(usize size, usize *out_padded_size) {
     usize alloc_size = os_pad_to_page(size);
@@ -605,11 +659,15 @@ bool os_thread_detach(oshandle_t thread) {
 bool os_thread_join(oshandle_t thread, int *code) {
     if (!os_handle_valid(thread)) return false;
     os_entity_t *entity = (os_entity_t *)thread.data;
-    int return_code = WaitForSingleObject(entity->thread.handle, INFINITE);
-    if (code) *code = return_code;
+    DWORD wait_result = WaitForSingleObject(entity->thread.handle, INFINITE);
+    if (code) {
+        DWORD exit_code = 0;
+        GetExitCodeThread(entity->thread.handle, &exit_code);
+        *code = exit_code;
+    }
     BOOL result = CloseHandle(entity->thread.handle);
     os__win_free_entity(entity);
-    return return_code != WAIT_FAILED && result;
+    return wait_result != WAIT_FAILED && result;
 }   
 
 u64 os_thread_get_id(oshandle_t thread) {