anchor.diff:        expect(fixedClock.now(), new DateTime(2014));
       });
   
  -    test("should return fixed time", () {
  +    test('should return fixed time', () {
         expect(new Clock.fixed(new DateTime(2013)).now(), new DateTime(2013));
       });
   
  -    test("should return time Duration ago", () {
  +    test('should return time Duration ago', () {
         expect(subject.agoBy(new Duration(days: 366)), new DateTime(2012));
       });
   
  -    test("should return time Duration from now", () {
  +    test('should return time Duration from now', () {
         expect(subject.fromNowBy(new Duration(days: 365)), new DateTime(2014));
       });
   
  -    test("should return time parts ago", () {
  +    test('should return time parts ago', () {
         expect(subject.ago(
             days: 1,
             hours: 1,
  
positive.code:       subject = new Clock.fixed(new DateTime(2013));
      });
  
      test("should return a non-null value from system clock", () {
        expect(new Clock().now(), isNotNull);
        expect(SYSTEM_CLOCK.now(), isNotNull);
      });
  
      // This test may be flaky on certain systems. I ran it over 10 million
      // cycles on my machine without any failures, but that's no guarantee.
      test("should be close enough to system clock", () {
        // At 10ms the test doesn't seem to be flaky.
        var epsilon = 10;
        expect(new DateTime.now().difference(
  
negative.code:           microseconds: 1000), new DateTime(2013, 1, 2, 1, 1, 1, 2));
      });
  
      test('should return time micros ago', () {
        expect(subject.microsAgo(1000),
            new DateTime(2012, 12, 31, 23, 59, 59, 999));
      });
  
      test('should return time micros from now', () {
        expect(subject.microsFromNow(1000),
            new DateTime(2013, 1, 1, 0, 0, 0, 1));
      });
  
      test('should return time millis ago', () {
        expect(subject.millisAgo(1000),
            new DateTime(2012, 12, 31, 23, 59, 59, 000));
      });
  
      test('should return time millis from now', () {
        expect(subject.millisFromNow(3),
            new DateTime(2013, 1, 1, 0, 0, 0, 3));
      });
  
      test('should return time seconds ago', () {
        expect(subject.secondsAgo(10),
            new DateTime(2012, 12, 31, 23, 59, 50, 000));
      });
  
      test('should return time seconds from now', () {
        expect(subject.secondsFromNow(3),
            new DateTime(2013, 1, 1, 0, 0, 3, 0));
      });
  
      test('should return time minutes ago', () {
        expect(subject.minutesAgo(10),
            new DateTime(2012, 12, 31, 23, 50, 0, 000));
      });
  
      test('should return time minutes from now', () {
        expect(subject.minutesFromNow(3),
            new DateTime(2013, 1, 1, 0, 3, 0, 0));
      });
  
      test('should return time hours ago', () {
        expect(subject.hoursAgo(10),
            new DateTime(2012, 12, 31, 14, 0, 0, 000));
      });
  
      test('should return time hours from now', () {
        expect(subject.hoursFromNow(3),
            new DateTime(2013, 1, 1, 3, 0, 0, 0));
      });
  
      test('should return time days ago', () {
        expectDate(subject.daysAgo(10), 2012, 12, 22);
      });
  
      test('should return time days from now', () {
        expectDate(subject.daysFromNow(3), 2013, 1, 4);
      });
  
      test('should return time months ago on the same date', () {
        expectDate(subject.monthsAgo(1), 2012, 12, 1);
        expectDate(subject.monthsAgo(2), 2012, 11, 1);
        expectDate(subject.monthsAgo(3), 2012, 10, 1);
        expectDate(subject.monthsAgo(4), 2012, 9, 1);
      });
  
      test('should return time months from now on the same date', () {
        expectDate(subject.monthsFromNow(1), 2013, 2, 1);
        expectDate(subject.monthsFromNow(2), 2013, 3, 1);
        expectDate(subject.monthsFromNow(3), 2013, 4, 1);
        expectDate(subject.monthsFromNow(4), 2013, 5, 1);
      });
  
      test('should go from 2013-05-31 to 2012-11-30', () {
        expectDate(from(2013, 5, 31).monthsAgo(6), 2012, 11, 30);
      });
  
      test('should go from 2013-03-31 to 2013-02-28 (common year)', () {
        expectDate(from(2013, 3, 31).monthsAgo(1), 2013, 2, 28);
      });
  
      test('should go from 2013-05-31 to 2013-02-28 (common year)', () {
        expectDate(from(2013, 5, 31).monthsAgo(3), 2013, 2, 28);
      });
  
      test('should go from 2004-03-31 to 2004-02-29 (leap year)', () {
        expectDate(from(2004, 3, 31).monthsAgo(1), 2004, 2, 29);
      });
  
      test('should go from 2013-03-31 to 2013-06-30', () {
        expectDate(from(2013, 3, 31).monthsFromNow(3), 2013, 6, 30);
      });
  
      test('should go from 2003-12-31 to 2004-02-29 (common to leap)', () {
        expectDate(from(2003, 12, 31).monthsFromNow(2), 2004, 2, 29);
      });
  
      test('should go from 2004-02-29 to 2003-02-28 by year', () {
        expectDate(from(2004, 2, 29).yearsAgo(1), 2003, 2, 28);
      });
  
      test('should go from 2004-02-29 to 2003-02-28 by month', () {
        expectDate(from(2004, 2, 29).monthsAgo(12), 2003, 2, 28);
      });
  
      test('should go from 2004-02-29 to 2005-02-28 by year', () {
        expectDate(from(2004, 2, 29).yearsFromNow(1), 2005, 2, 28);
      });
  
      test('should go from 2004-02-29 to 2005-02-28 by month', () {
        expectDate(from(2004, 2, 29).monthsFromNow(12), 2005, 2, 28);
      });
  
      test('should return time years ago on the same date', () {
        expectDate(subject.yearsAgo(1), 2012, 1, 1);  // leap year
        expectDate(subject.yearsAgo(2), 2011, 1, 1);
        expectDate(subject.yearsAgo(3), 2010, 1, 1);
  