TimerTest.java

package org.mockito.internal.util;

import org.assertj.core.api.Assertions;
import org.junit.Assert;
import org.junit.Test;
import org.mockito.exceptions.misusing.FriendlyReminderException;
import org.mockitoutil.TestBase;

public class TimerTest extends TestBase {

    @Test
    public void should_return_true_if_task_is_in_acceptable_time_bounds() {
        //given
        long duration = 10000L;
        Timer timer = new Timer(duration);

        //when
        timer.start();

        //then
        Assertions.assertThat(timer.isCounting()).isTrue();
    }

    @Test
    public void should_return_false_when_time_run_out() throws Exception {
        //given
        Timer timer = new Timer(0);
        timer.start();

        //when
        oneMillisecondPasses();

        //then
        Assertions.assertThat(timer.isCounting()).isFalse();
    }

    @Test
    public void should_throw_friendly_reminder_exception_when_duration_is_negative() {
        try {
            new Timer(-1);
            Assert.fail("It is forbidden to create timer with negative value of timer's duration.");
        } catch (FriendlyReminderException e) {
            Assert.assertTrue(true);
        }
    }

    private void oneMillisecondPasses() throws InterruptedException {
        Thread.sleep(1);
    }
}