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四  when语句

1  when().thenReturn()模式

声明：

PowerMockito.when(mockObject.someMethod(someArgs)).thenReturn(expectedValue);

PowerMockito.when(mockObject.someMethod(someArgs)).thenThrow(expectedThrowable);

PowerMockito.when(mockObject.someMethod(someArgs)).thenAnswer(expectedAnswer);

PowerMockito.when(mockObject.someMethod(someArgs)).thenCallRealMethod();

用途：用于模拟对象方法，先执行原始方法，再返回期望的值、异常、应答，或调用真实的方法。

返回期望值

public class ListTest {

   @Test

   public void testGet() {

       int index = 0;

       Integer expected = 100;

       List<Integer> mockList = PowerMockito.mock(List.class);

       PowerMockito.when(mockList.get(index)).thenReturn(expected);

       Integer actual = mockList.get(index);

       Assert.assertEquals("返回值不相等", expected, actual);

   }

}

返回期望异常

public class ListTest {

   @Test(expected = IndexOutOfBoundsException.class)

   public void testGet() {

       int index = -1;

       Integer expected = 100;

       List<Integer> mockList = PowerMockito.mock(List.class);

       PowerMockito.when(mockList.get(index)).thenThrow(new IndexOutOfBoundsException());

       Integer actual = mockList.get(index);

       Assert.assertEquals("返回值不相等", expected, actual);

   }

}

返回期望应答

public class ListTest {

   @Test

   public void testGet() {

       int index = 1;

       Integer expected = 100;

       List<Integer> mockList = PowerMockito.mock(List.class);

       PowerMockito.when(mockList.get(index)).thenAnswer(invocation -> {

           Integer value = invocation.getArgument(0);

           return value * 100;

       });

       Integer actual = mockList.get(index);

       Assert.assertEquals("返回值不相等", expected, actual);

   }

}

调用真实方法

public class ListTest {

   @Test

   public void testGet() {

       int index = 0;

       Integer expected = 100;

       List<Integer> oldList = new ArrayList<>();

       oldList.add(expected);

       List<Integer> spylist = PowerMockito.spy(oldList);

       PowerMockito.when(spylist.get(index)).thenCallRealMethod();

       Integer actual = spylist.get(index);

       Assert.assertEquals("返回值不相等", expected, actual);

   }

}

2  doReturn().when()模式

声明：

PowerMockito.doReturn(expectedValue).when(mockObject).someMethod(someArgs);

PowerMockito.doThrow(expectedThrowable).when(mockObject).someMethod(someArgs);

PowerMockito.doAnswer(expectedAnswer).when(mockObject).someMethod(someArgs);

PowerMockito.doNothing().when(mockObject).someMethod(someArgs);

PowerMockito.doCallRealMethod().when(mockObject).someMethod(someArgs);

用途：用于模拟对象方法，直接返回期望的值、异常、应答，或调用真实的方法，无需执行原始方法。

注意，千万不要使用以下语法：

PowerMockito.doReturn(expectedValue).when(mockObject.someMethod(someArgs));

PowerMockito.doThrow(expectedThrowable).when(mockObject.someMethod(someArgs));

PowerMockito.doAnswer(expectedAnswer).when(mockObject.someMethod(someArgs));

PowerMockito.doNothing().when(mockObject.someMethod(someArgs));

PowerMockito.doCallRealMethod().when(mockObject.someMethod(someArgs));

虽然不会出现编译错误，但是在执行时会抛出UnfinishedStubbingException异常。

返回期望值

public class ListTest {

   @Test

   public void testGet() {

       int index = 0;

       Integer expected = 100;

       List<Integer> mockList = PowerMockito.mock(List.class);

       PowerMockito.doReturn(expected).when(mockList).get(index);

       Integer actual = mockList.get(index);

       Assert.assertEquals("返回值不相等", expected, actual);

   }

}

返回期望异常

public class ListTest {

   @Test(expected = IndexOutOfBoundsException.class)

   public void testGet() {

       int index = -1;

       Integer expected = 100;

       List<Integer> mockList = PowerMockito.mock(List.class);

       PowerMockito.doThrow(new IndexOutOfBoundsException()).when(mockList).get(index);

       Integer actual = mockList.get(index);

       Assert.assertEquals("返回值不相等", expected, actual);

   }

}

返回期望应答

public class ListTest {

   @Test(expected = IndexOutOfBoundsException.class)

   public void testGet() {

       int index = -1;

       Integer expected = 100;

       List<Integer> mockList = PowerMockito.mock(List.class);

       PowerMockito.doThrow(new IndexOutOfBoundsException()).when(mockList).get(index);

       Integer actual = mockList.get(index);

       Assert.assertEquals("返回值不相等", expected, actual);

   }

}

模拟无返回值

public class ListTest {

   @Test

   public void testGet() {

       int index = 1;

       Integer expected = 100;

       List<Integer> mockList = PowerMockito.mock(List.class);

       PowerMockito.doAnswer(invocation -> {

           Integer value = invocation.getArgument(0);

           return value * 100;

       }).when(mockList).get(index);

       Integer actual = mockList.get(index);

       Assert.assertEquals("返回值不相等", expected, actual);

   }

}

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