Junit Mockito Test Dependent Class Attribute

Question

目标是使用 mockito 执行单元测试。在第一个练习中，我创建了依赖类属性的虚拟对象并测试了该类，它工作正常。

现在我想使用 mockito 模拟未直接测试的类属性。但是我得到了NullPointerException。恳请指教。

        java.lang.NullPointerException
        at edu.uncc.ssdi.FlightReservation.<init>(FlightReservation.java:25)
        at edu.uncc.ssdi.FlightReservationTest.testFlightReservation_ParaConstructor(FlightReservationTest.java:44)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
        at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
        at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
        at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
        at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
        at org.mockito.internal.junit.JUnitRule$1.evaluateSafely(JUnitRule.java:52)
        at org.mockito.internal.junit.JUnitRule$1.evaluate(JUnitRule.java:43)
        at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
        at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
        at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
        at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
        at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
        at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
        at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
        at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
        at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
        at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
        at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
        at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
        at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
        at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
        at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)

航班预订测试

        import static org.junit.Assert.assertEquals;
        import java.text.ParseException;
        import java.text.SimpleDateFormat;
        import java.util.Date;
        import org.junit.Before;
        import org.junit.Rule;
        import org.junit.Test;
        import org.mockito.Mock;
        import org.mockito.Mockito;
        import org.mockito.junit.MockitoJUnit;
        import org.mockito.junit.MockitoRule;
        public class FlightReservationTest {
        @Mock
        private Flight tempFlight;
        private Date tempDate;
        @Rule
        public MockitoRule rule = MockitoJUnit.rule();
        @Before
        public void setup() {
            tempDate = new Date();
        }
        @Test
        public void testFlightReservation_ParaConstructor() {
            try {
                Date date1 = new SimpleDateFormat("dd/MM/yyyy").parse("26/05/2018");
                // tempFlight = new Flight("s1","s2","s3","s4",date1,date1,100);
                FlightReservation fRes1 = new FlightReservation(tempFlight, tempDate, 1, 1);
                Mockito.when(tempFlight.getDepartureDate()).thenReturn(date1);
                Mockito.when(tempFlight.getArrivalDate()).thenReturn(date1);
                Mockito.when(tempFlight.getOriginAirport()).thenReturn("s1");
                Mockito.when(tempFlight.getDestinationAirport()).thenReturn("s1");
                assertEquals(tempFlight, fRes1.flightType);
                assertEquals(tempDate, fRes1.flightReservationDate);
                assertEquals(1, fRes1.noOfAdult);
                assertEquals(1, fRes1.noOfChildren);
            } catch (ReservationException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (ParseException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        }

航班预订

     import java.util.Date;
    public class FlightReservation {
        public Flight flightType;
        public Date flightReservationDate;
        public int noOfAdult;
        public int noOfChildren;
        public FlightReservation() {
            flightType = null;
            flightReservationDate = null;
            noOfAdult = 0;
            noOfChildren = 0;
        }
        public FlightReservation(Flight flightType, Date flightReservationDate, int noOfAdult, int noOfChildren)
                throws ReservationException {
            super();
            String flightDetails = flightType.getOriginAirport() + "-->" + flightType.getDestinationAirport();
            if (flightType.getDepartureDate().compareTo(flightReservationDate) < 0)
                throw new ReservationException(
                        "Departure Date must be atleast 1 day after Reservation/System Date " + flightDetails);
            if (flightType.getArrivalDate().compareTo(flightType.getDepartureDate()) < 0)
                throw new ReservationException("Arrival Date is before Departure Date" + ": " + flightDetails);
            if (!checkAdultNo(noOfAdult))
                throw new ReservationException("No of Adult cannot be less than 1" + ": " + flightDetails);
            this.flightType = flightType;
            this.flightReservationDate = flightReservationDate;
            this.noOfAdult = noOfAdult;
            this.noOfChildren = noOfChildren;
        }
        public boolean checkAdultNo(int noOfAdult) {
            boolean flag = true;
            if (noOfAdult < 1) {
                flag = false;
            }
            return flag;
        }
    }

Answer 1

一旦你测试了构造函数，你实际上就不需要模拟这些东西了。您可以构建必要的对象，仅此而已。

但是，如果您使用的是 Mockito API 注释，则应在类上使用 @RunWith(MockitoJUnitRunner.class( 注释，以使 Mockito 注释正常工作。

PowerMock 有 whenNew(( 方法用于这种特定情况，但我真的不建议它只是为了这个。