@RunWith(PowerMockRunner.class)
@PrepareForTest({ Calendar.class })

public void determineDefaultMaximumScans() throws ParseException{
parseTime();
Calendar cal = Calendar.getInstance();
int dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
System.out.println(cal.get(Calendar.DAY_OF_WEEK));

if(dayOfWeek == (Calendar.SATURDAY) || dayOfWeek == (Calendar.SUNDAY)){
        setDefaultMax(calculateNewDefaultMax(getDefaultMax()));
        System.out.println("defaultMax increased by 20%");
    } else {
        if(currentTime.after(afterHoursBegin) && currentTime.before(afterHoursEnd)){
            System.out.println("Not afterhours. Maintaining current maximum.");
            setDefaultMax(defaultMax);
            System.out.println("Current Maximum number of scans: " + getDefaultMax());
        }

    }
}

@SuppressWarnings("static-access")
@Test
public void testDetermineMaximumScans() throws ParseException{
    PowerMock.mockStatic(Calendar.class);
    String beginningTime = "18:00";
    String endingTime = "05:00";

    mockAfterHoursBegin = parser.parse(beginningTime);
    mockAfterHoursEnd = parser.parse(endingTime);
    mockCurrentTime = parser.parse(parser.format(new Date()));

    EasyMock.expect(Calendar.getInstance()).andReturn(mockCalendar);
    EasyMock.expect(mockCalendar.get(Calendar.DAY_OF_WEEK)).andReturn(6);


    EasyMock.replay(mocks);
    offHourMaximumCalculator.determineDefaultMaximumScans();
    EasyMock.verify(mocks);
}

java.lang.AssertionError:
  Expectation failure on verify:
Calendar.get(7): expected: 1, actual: 0

protected Calendar newCalendar() {
    return Calendar.getInstance(); // or new GregorianCalendar()
}

@RunWith(PowerMockRunner.class)
@PrepareForTest(Calendar.class)
public class MyTest {

  @Test
  public void testDetermineMaximumScans() throws ParseException {
    PowerMock.mockStatic(Calendar.class);

    Calendar calendar = mock(Calendar.class);

    EasyMock.expect(Calendar.getInstance()).andReturn(calendar);
    EasyMock.expect(calendar.get(Calendar.DAY_OF_WEEK)).andReturn(6);

    // really important to replayAll to replay the static expectation
    PowerMock.replayAll(calendar);
    assertThat(Calendar.getInstance().get(Calendar.DAY_OF_WEEK)).isEqualTo(6);

    // and verifyAll is you want to verify that the static call actually happened
    PowerMock.verifyAll();
  }

}