public function data_test_human_time_diff() {
    return array(
      array(
        '37 seconds',
        new DateTime( '2016-01-01 12:00:37' ),
        'Test a difference of 37 seconds.',
      ),
      array(
        '5 mins',
        new DateTime( '2016-01-01 12:05:00' ),
        'Test a difference of 5 minutes.',
      ),
      array(
        '1 hour',
        new DateTime( '2016-01-01 13:00:00' ),
        'Test a difference of 1 hour.',
      ),
      array(
        '2 days',
        new DateTime( '2016-01-03 12:00:00' ),
        'Test a difference of 2 days.',
      ),
      array(
        '2 hours',
        new DateTime( '2016-01-01 14:29:59' ),
        'Test a difference of 2 hours, 29 minutes and 59 seconds  - should round down to 2 hours.',
      ),
      array(
        '3 hours',
        new DateTime( '2016-01-01 14:30:00' ),
        'Test a difference of 2 hours and 30 minutes - should round up to 3 hours.',
      ),
      array(
        '2 months',
        new DateTime( '2016-02-15 12:00:00' ),
        'Test a difference of 1 month and 15 days - should round up to 2 months.',
      ),
      array(
        '1 month',
        new DateTime( '2016-02-14 12:00:00' ),
        'Test a difference of 1 month and 14 days - should round down to 1 month.',
      ),
      array(
        '3 years',
        new DateTime( '2018-07-02 12:00:00' ),
        'Test a difference of 2 years 6 months and 1 day, should round up to 3 years.',
      ),
      array(
        '2 years',
        new DateTime( '2018-07-01 12:00:00' ),
        'Test a difference of 2 years 6 months, should round down to 2 years.',
      ),
    );
  }