Add test for Arena's reallocation functionality

tests/arena/test_arena.c

@@ -47,6 +47,52 @@ TestFuncResult test_arena_alloc_fails_when_over_capacity(void) {
   return wapp_tester_result(result);
 }
 
+TestFuncResult test_arena_realloc_bigger_size(void) {
+  u64 count     = 10;
+  u64 new_count = 20;
+  i32 *bytes    = wapp_mem_arena_alloc(arena, count * sizeof(i32));
+
+  for (u64 i = 0; i < count; ++i) {
+    bytes[i] = i;
+  }
+
+  i32 *new_bytes = wapp_mem_arena_realloc(arena, bytes, count * sizeof(i32), new_count * sizeof(i32));
+  if (!new_bytes) {
+    return wapp_tester_result(false);
+  }
+
+  for (u64 i = 0; i < new_count; ++i) {
+    if (i < count && new_bytes[i] != bytes[i]) {
+      return wapp_tester_result(false);
+    }
+  }
+
+  return wapp_tester_result(true);
+}
+
+TestFuncResult test_arena_realloc_smaller_size(void) {
+  u64 count     = 10;
+  u64 new_count = 5;
+  i32 *bytes    = wapp_mem_arena_alloc(arena, count * sizeof(i32));
+
+  for (u64 i = 0; i < count; ++i) {
+    bytes[i] = i;
+  }
+
+  i32 *new_bytes = wapp_mem_arena_realloc(arena, bytes, count * sizeof(i32), new_count * sizeof(i32));
+  if (!new_bytes) {
+    return wapp_tester_result(false);
+  }
+
+  for (u64 i = 0; i < new_count; ++i) {
+    if (i < new_count && new_bytes[i] != bytes[i]) {
+      return wapp_tester_result(false);
+    }
+  }
+
+  return wapp_tester_result(true);
+}
+
 TestFuncResult test_arena_clear(void) {
   wapp_mem_arena_clear(arena);
   bool result = true;

tests/arena/test_arena.h

@@ -11,6 +11,8 @@ TestFuncResult test_arena_init(void);
 TestFuncResult test_arena_init_succeeds_when_reserving_very_large_size(void);
 TestFuncResult test_arena_alloc_succeeds_when_within_capacity(void);
 TestFuncResult test_arena_alloc_fails_when_over_capacity(void);
+TestFuncResult test_arena_realloc_bigger_size(void);
+TestFuncResult test_arena_realloc_smaller_size(void);
 TestFuncResult test_arena_clear(void);
 TestFuncResult test_arena_destroy(void);