Re: [PATCH v8 0/1] MR3959: uxtheme: Add ShouldSystemUseDarkMode.

[Zhiyi Zhang (＠zhiyi)]

Zhiyi Zhang (@zhiyi) commented about dlls/uxtheme/tests/system.c:
> - /* Call ShouldSystemUseDarkMode() and check for errors */
> - SetLastError(ERROR_SUCCESS); /* Clear error buffer so that we can detect if an error occurred. */
> - function_result = pShouldSystemUseDarkMode();
> - last_error = GetLastError();
> - ok(last_error == ERROR_SUCCESS, "ShouldSystemUseDarkMode failed (?) with error %ld.\n",
> -
>   last_error);
> -
> - /* Expect same value as key */
> - ok(function_result == !system_uses_light_theme, "Expected value %d, got %d.\n",
> -
>   !system_uses_light_theme, function_result);
> -
> - ls = RegDeleteValueA(hk, "AppsUseLightTheme");
> - ok(ls == 0, "RegDeleteValueA failed: %ld.\n", ls);
> -
> - /* Call ShouldSystemUseDarkMode() and check for errors with deleted value */
> - SetLastError(ERROR_SUCCESS); /* Clear error buffer so that we can detect if an error occurred. */

For the last error code. You can SetLastError(0xdeadbeef) before the call and check that the last error is set to ERROR_SUCCESS after the call. And then you set the last error code in the ShouldSystemUseDarkMode() implementation.