Excerpt from https://gist.github.com/zethraeus/34d2aa882c106d8f44ecda6a976361db#file-badonboardingmanagertests-swift

BadOnboardingManagerTestExcerpt.swift

func test_PasswordCanNotContainUsername() {
    let mockPasswordCollectorLauncher = MockPasswordCollectorLauncher()
    let mockListener = MockOnboardingManagerListener()

    let onboardingManager = BadOnboardingManager(passwordCollectorLauncher: mockPasswordCollectorLauncher)
    onboardingManager.listener = mockListener

    onboardingManager.start()
    // TODO: assert the username collector launches now.
    onboardingManager.usernameCollectorReturned(username: "ValidUsername")
    // TODO: assert the email collector launches now.
    onboardingManager.emailCollectorReturned(email: "valid@example.com")
    // TODO: assert the phone number collector launches now.
    XCTAssertEqual(mockPasswordCollectorLauncher.launchCallCount, 0)
    onboardingManager.phoneNumberCollectorReturned(number: "+11235554321")
    XCTAssertEqual(mockPasswordCollectorLauncher.launchCallCount, 1)
    XCTAssertEqual(mockPasswordCollectorLauncher.existingPasswordIssueValues.last, nil)

    onboardingManager.passwordCollectorReturned(password: "ValidUsername$123")
    XCTAssertEqual(mockPasswordCollectorLauncher.launchCallCount, 2)
    XCTAssertEqual(mockPasswordCollectorLauncher.existingPasswordIssueValues.last, PasswordIssue.containsUsername)
}