JUnit和Mockito的分支覆盖范围

Question

我正在为一个方法使用JUnitAPI编写一个测试用例。我已经介绍了所有的场景，但让我感到困难的是if块。当我将鼠标悬停在这条线上时，Cobertura会为每个条件声明50%50%，但我不确定如何覆盖这一点。

试验方法：

protected boolean isDateWithinTimelineRange( Calendar date, ServiceContext ctx ) {
Calendar end = (Calendar)ctx.getParameter( ServiceConstants.TIMELINE_END );
Calendar start = (Calendar)ctx.getParameter( ServiceConstants.TIMELINE_BEGIN );
if( end != null && start != null ) {
if( date.getTimeInMillis() >= start.getTimeInMillis() && date.getTimeInMillis() <= end.getTimeInMillis() ) {
return true;
} else {
return false;
}
}
return true;
}

JUnit测试用例：

@Test
public void testIsDateWithinTimelineRange() throws Exception {
ServiceContext context = Mockito.mock(ServiceContext.class);
Calendar calender = Mockito.mock(Calendar.class);
Mockito.when(context.getParameter(Mockito.anyString())).thenReturn(calender);
TestBaseTimelineProvider provider = new TestBaseTimelineProvider();
boolean answer = provider.isDateWithinTimelineRange(calender, context);
assertNotNull(answer);
assertTrue(provider.isDateWithinTimelineRange(calender, context));
// Testing for NULL condition
context = Mockito.mock(ServiceContext.class);
calender = Mockito.mock(Calendar.class);
Mockito.when(context.getParameter(Mockito.anyString())).thenReturn(null);
provider = new TestBaseTimelineProvider();
answer = provider.isDateWithinTimelineRange(calender, context);
assertNotNull(answer);
assertTrue(provider.isDateWithinTimelineRange(calender, context));
// Start date set to null
context = Mockito.mock(ServiceContext.class);
calender = Mockito.mock(Calendar.class);
ServiceConstants constants = new ServiceConstants();
Mockito.when(context.getParameter(ServiceConstants.TIMELINE_END)).thenReturn(calender);
provider = new TestBaseTimelineProvider();
answer = provider.isDateWithinTimelineRange(calender, context);
assertNotNull(constants);
// End date set to null
context = Mockito.mock(ServiceContext.class);
calender = Mockito.mock(Calendar.class);
constants = new ServiceConstants();
Mockito.when(context.getParameter(ServiceConstants.TIMELINE_BEGIN)).thenReturn(calender);
provider = new TestBaseTimelineProvider();
answer = provider.isDateWithinTimelineRange(calender, context);
assertNotNull(constants);
}

让我困惑的是我正在嘲笑的参数date，它决定了end和start变量的值。

if( date.getTimeInMillis() >= start.getTimeInMillis() && date.getTimeInMillis() <= end.getTimeInMillis() ) {}是我想覆盖的线路。

感谢

Answer 1

首先，当调用getTimeInMillis()时，您从未告诉您的模拟日历对象该做什么。您需要为每个日历条目添加以下内容：

// Assume `long desiredlong` defined;
Mockito.when(calendar.getTimeInMillis()).thenReturn(desiredlong);

您需要对date.getTimeInMillis()在所需范围内的一组日历对象和date.getTimeInMillis)在所述范围外的另一组对象执行此操作。

最终，涵盖该测试真实一面的案例将采用以下形式：

@Test
public void validDatesInRange() {
ServiceContext context = Mockito.mock(ServiceContext.class);
Calendar calenderstart = Mockito.mock(Calendar.class);
Mockito.when(calendarstart.getTimeInMillis()).thenReturn(1L);
Calendar calendertarget = Mockito.mock(Calendar.class);
Mockito.when(calendartarget.getTimeInMillis()).thenReturn(2L);
Calendar calenderend = Mockito.mock(Calendar.class);
Mockito.when(calendarend.getTimeInMillis()).thenReturn(3L);
Mockito.when(context.getParameter(ServiceConstants.TIMELINE_END)).thenReturn(calenderend);
Mockito.when(context.getParameter(ServiceConstants.TIMELINE_BEGIN)).thenReturn(calenderstart);
TestBaseTimelineProvider provider = new TestBaseTimelineProvider();
boolean answer = provider.isDateWithinTimelineRange(calendertarget, context);
assertNotNull(answer);
assertTrue(provider.isDateWithinTimelineRange(calendartarget, context));
}

其次，你从来没有真正写过任何测试错误返回的东西。为了覆盖另一面，复制上面的内容，但将calendartarget.getTimeInMillis()设置为返回类似1000L的荒谬内容，并将断言更改为反映false。

您可能还希望将测试用例分解为多个方法，这些方法的名称反映了每个测试方法所检查的内容，如validDatesInRange()、validDatesNotInRange()、startDateIsNull()、endDateIsNull()、contextIsNull()。通过这样做，您的测试变得更小，更容易理解和调试，测试运行会生成更干净、信息更丰富的测试报告，并且一个测试中的失败不会掩盖其他测试中的错误。