Driving app state via launch arguments in XCUITest

WHAT IT TESTS: whether you configure preconditions out of band instead of re-driving the UI. ANSWER OUTLINE: set XCUIApplication.launchArguments and launchEnvironment before launch; the app reads them at startup to inject a logged-in session, toggle feature flags, or select a stub backend, so each test begins in the required state instantly. Centralize this in a helper or base test class. RED FLAG: performing the full login flow through taps in every test, which is slow, flaky, and couples unrelated tests to the auth screen.