unit testing - Xcode: TEST vs DEBUG preprocessor macros

Question

When creating a new project with unit tests, Xcode sets the build configuration to Debug for the Test scheme (same for the Run scheme).

Should I differentiate between Run (Command-R) & Test (Command-U) schemes?

I.e., should I create a new Build Configuration called Test, add a preprocessor macro TEST=1 to it, and use it as the build configuration for the Test scheme instead? Or, should I just keep Run & Test both as Debug?

I come from a Ruby/Rails background, where you usually have test, development, and production environments. It seems to me that Debug is like development and Release is like production, but we're missing a test, which is why I'm thinking it might make sense to add Test.

Comments? Opinions? Suggestions?

I'm specifically asking this because I want to compile something for Test with:

#ifdef TEST
// Do something when I test.
#endif

I don't think it matters if I also compile this for Debug. So, I really could just do:

#ifdef DEBUG
// Do something when I run or test.
#endif

But, I'm really only intending to do it for tests for now. So, that's why I'm thinking I should differentiate between debug & test but am wondering why Xcode doesn't do that for you by default? Does Apple think you shouldn't differentiate between them?

Answer 1

Preprocessor macros will not work, you need to check the environment at runtime.

Objective-c

static BOOL isRunningTests(void)
{
    NSDictionary* environment = [[NSProcessInfo processInfo] environment];
    return (environment[@"XCTestConfigurationFilePath"] != nil);
}

Swift

var unitTesting : Bool 
{
    return ProcessInfo.processInfo.environment["XCTestConfigurationFilePath"] != nil
}

(Updated for Xcode 11)