### Question:
Stopwatch { public void stop() { if (!running) throw new IllegalStateException(); elapsed = ticks.ticks() - start; running = false; } Stopwatch(Ticks ticks); long elapsedNanos(); void start(); void stop(); final static Ticks SYSTEM_TICKS; }### Answer:
@Test(expected = IllegalStateException.class) public void testNotStarted2() { FakeTicks f = new FakeTicks(); Stopwatch s = new Stopwatch(f); s.stop(); }