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 betwee

Answer 1

Robert's answer in SWIFT 3.0:

func isRunningTests() -> Bool {
    let environment = ProcessInfo().environment
    return (environment["XCInjectBundleInto"] != nil);
}