Port filesystem to ubuntu, add filesystem tests

test/data/append_file

@@ -0,0 +1 @@
+WRITE OK APPEND OK

test/data/read_file

@@ -0,0 +1 @@
+OK

test/data/write_file

@@ -0,0 +1 @@
+WRITE2 OK

test/test_filesystem.c

@@ -0,0 +1,105 @@
+#include "../core.c"
+
+int main() {
+    MA_Arena arena = {};
+    S8_String read_file_path = S8_Lit("../test/data/read_file");
+
+    // Read file test
+    {
+        S8_String file = OS_ReadFile(&arena, read_file_path);
+        IO_Assert(S8_AreEqual(file, S8_Lit("OK"), 0));
+    }
+
+    // Write file test
+    {
+        S8_String path = S8_Lit("../test/data/write_file");
+        {
+            S8_String data = S8_Lit("WRITE1 OK");
+            OS_Result result = OS_WriteFile(path, data);
+            IO_Assert(result == OS_SUCCESS);
+
+            S8_String read = OS_ReadFile(&arena, path);
+            IO_Assert(S8_AreEqual(read, data, 0));
+        }
+        S8_String data = S8_Lit("WRITE2 OK");
+
+        OS_Result result = OS_WriteFile(path, data);
+        IO_Assert(result == OS_SUCCESS);
+
+        S8_String read = OS_ReadFile(&arena, path);
+        IO_Assert(S8_AreEqual(read, data, 0));
+    }
+
+    // Append file test
+    {
+        S8_String path = S8_Lit("../test/data/append_file");
+        {
+            S8_String data = S8_Lit("WRITE OK");
+            OS_Result result = OS_WriteFile(path, data);
+            IO_Assert(result == OS_SUCCESS);
+        }
+        S8_String data = S8_Lit(" APPEND OK");
+        OS_Result result = OS_AppendFile(path, data);
+        IO_Assert(result == OS_SUCCESS);
+
+        S8_String read = OS_ReadFile(&arena, path);
+        IO_Assert(S8_AreEqual(read, S8_Lit("WRITE OK APPEND OK"), 0));
+    }
+
+    IO_Assert(OS_FileExists(read_file_path));
+    IO_Assert(!OS_FileExists(S8_Lit("121ffsadasd.random")));
+
+    // Fetching dirs
+    {
+        S8_String exe_path = OS_GetExePath(&arena);
+        S8_String dir_path = OS_GetExeDir(&arena);
+        S8_String work_path = OS_GetWorkingDir(&arena);
+        S8_String abs_path = OS_GetAbsolutePath(&arena, read_file_path);
+        // IO_Printf("Exe path = %Q\n", exe_path);
+        // IO_Printf("Dir path = %Q\n", dir_path);
+        // IO_Printf("Working path = %Q\n", work_path);
+        // IO_Printf("Abs path = %Q\n", abs_path);
+
+        IO_Assert(OS_IsDir(dir_path));
+        IO_Assert(!OS_IsFile(dir_path));
+
+        IO_Assert(OS_IsFile(exe_path));
+        IO_Assert(!OS_IsDir(exe_path));
+
+        IO_Assert(OS_IsAbsolute(exe_path));
+        IO_Assert(OS_IsAbsolute(dir_path));
+        IO_Assert(OS_IsAbsolute(work_path));
+        IO_Assert(OS_IsAbsolute(abs_path));
+
+        IO_Assert(S8_Find(exe_path, S8_Lit("/test_filesystem"), 0, 0));
+        IO_Assert(S8_Find(exe_path, S8_Lit("/build"), 0, 0));
+        IO_Assert(S8_Find(dir_path, S8_Lit("/build"), 0, 0));
+        IO_Assert(S8_Find(work_path, S8_Lit("/build"), 0, 0));
+        IO_Assert(S8_Find(abs_path, S8_Lit("/test/data"), 0, 0));
+        IO_Assert(!S8_Find(abs_path, S8_Lit("../"), 0, 0));
+    }
+
+    // List dir test
+    {
+        S8_List list = OS_ListDir(&arena, S8_Lit("../test"), 0);
+        IO_Assert(list.node_count > 4);
+        int dir_count = 0;
+        S8_For(it, list) {
+            if (OS_IsDir(it->string)) {
+                IO_Assert(it->string.str[it->string.len - 1] == '/');
+                dir_count += 1;
+            }
+            IO_Assert(S8_Find(it->string, S8_Lit("/test"), 0, 0));
+            IO_Assert(!S8_Find(it->string, S8_Lit("../test"), 0, 0));
+        }
+        IO_Assert(dir_count > 0);
+
+        // relative
+        {
+            S8_List list = OS_ListDir(&arena, S8_Lit("../test"), OS_RELATIVE_PATHS);
+            S8_For(it, list) {
+                IO_Assert(S8_Find(it->string, S8_Lit("../test"), 0, 0));
+            }
+        }
+    }
+}