All you ever need test utils (https://godbolt.org/z/WEoavaqGc)

test_util.c

#include <stdio.h>

#define STR1(s) # s
#define STR(s) STR1(s)

#define TEST_EXPECT(condition) test_expect(!!(condition), __FILE__ ":" STR(__LINE__) ": (" STR(condition) ") expected to be true\n")

static inline void test_expect(int condition, const char *msg) {
  if (!condition) {
    fputs(msg, stderr);
    
    // __debugbreak and __builtin_debugtrap() would allow SIGTRAPping into a debugger
    // __builtin_trap generates SIGILL and code after it will be optmized away.
#if defined(_MSC_VER)
    __debugbreak();
#elif defined(__clang__)
    __builtin_debugtrap();
#else
    __builtin_trap(); // gcc doesn't have __builtin_debugtrap equivalent
#endif
  }
}

int main(void) {
  int one = 1;

  fputs("--- First TEST_EXPECT succeds\n", stderr);
  TEST_EXPECT(one == 1);

  fputs("--- Second TEST_EXPECT breaks into debugger or crashes\n", stderr);
  TEST_EXPECT(one == 2);

  fputs("--- This line won't be printed!\n", stderr);
  return 0;
}