@Test
public void execute_singleRunnable_executionSuccessful() throws Exception {

    // Arrange
    final Semaphore semaphore = new Semaphore(0);
    Runnable runnable = new Runnable() {
        @Override
        public void run() {
            semaphore.release();
        }
    };
    // Act
    SUT.post(runnable);
    // Assert
    semaphore.acquireUninterruptibly();
}