Utility Method for TDD

ViewControllerUITests.swift

func playWithAutomatic(number:Int) {
    let app = XCUIApplication()
    let numberButton = app.buttons["number"]
    let fizzButton = app.buttons["fizz"]
    let buzzButton = app.buttons["buzz"]
    let fizzBuzzButton = app.buttons["fizzbuzz"]
    
    for index in 0...number {
        if index%15==0 {
            fizzBuzzButton.tap()
        }
        else if index%5==0 {
            buzzButton.tap()
        }
        else if index%3==0 {
            fizzButton.tap()
        }
        else {
            numberButton.tap()
        }
    }
}

func testTapFizzBuzzButtonIncrementsTo15() {
    let app = XCUIApplication()
    let numberButton = app.buttons["number"]
    playWithAutomatic(15)
    XCTAssertEqual(numberButton.label, "15")
}