diff --git a/src/mem/arena/mem_arena.c b/src/mem/arena/mem_arena.c
index 2797fb7..ea1934c 100644
--- a/src/mem/arena/mem_arena.c
+++ b/src/mem/arena/mem_arena.c
@@ -1,6 +1,7 @@
 #include "mem_arena.h"
 #include "aliases.h"
 #include "mem_utils.h"
+#include "misc_utils.h"
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
@@ -18,6 +19,10 @@ struct arena {
   u8 *offset;
   u64 capacity;
   bool committed;
+
+#ifdef WAPP_PLATFORM_WINDOWS
+  wapp_misc_utils_padding_size(sizeof(u8 *) * 2 + sizeof(u64) + sizeof(bool));
+#endif // ifdef WAPP_PLATFORM_WINDOWS
 };
 
 // PUBLIC API
diff --git a/src/tester/tester.h b/src/tester/tester.h
index 6eec3fe..1e182f8 100644
--- a/src/tester/tester.h
+++ b/src/tester/tester.h
@@ -1,20 +1,26 @@
 #ifndef TESTER_H
 #define TESTER_H
 
+#include "misc_utils.h"
+#include "platform.h"
 #include <stdbool.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif // __cplusplus
 
-#define wapp_tester_result(test_passed)                                        \
-  ((TestFuncResult){.name = __func__, .passed = test_passed})
+#define wapp_tester_result(PASSED)                                             \
+  ((TestFuncResult){.name = __func__, .passed = PASSED})
 #define wapp_tester_run_tests(...) run_tests(__VA_ARGS__, NULL)
 
 typedef struct test_func_result TestFuncResult;
 struct test_func_result {
   const char *name;
   bool passed;
+
+#ifdef WAPP_PLATFORM_WINDOWS
+  wapp_misc_utils_padding_size(sizeof(const char *) + sizeof(bool));
+#endif // WAPP_PLATFORM_WINDOWS
 };
 
 typedef TestFuncResult(TestFunc)(void);