如何使用PowerMockito和JUnit模拟getResourceAsStream方法? [英] How to mock getResourceAsStream method using PowerMockito and JUnit?

问题描述

我尝试模拟在构造函数中调用的getResourceAsStream方法.

I try to mock getResourceAsStream method which I invoke in constructor.

public Conn() {
    stream = Conn.class.getClass().getResourceAsStream(PATH);
}

对于模拟框架，我更喜欢Mockito + PowerMockito.

For mock framework I prefer Mockito + PowerMockito.

    @RunWith(PowerMockRunner.class)
    @PrepareForTest(Conn.class)
    public class ConnTest {

        @Mock
        private InputStream streamMock;

        private Conn conn;

        @Before
        public void before() {
            initMocks(this);
        }

        @Test
        public void test() {    
            PowerMockito.mockStatic(Conn.class);
            PowerMockito.when(Connector.class.getResourceAsStream("/prop.properties")).thenReturn(streamMock);
            conn = new Conn();
        }

        @After
        public void after() {
            reset(streamMock);
        }
     }

但是方法thenReturn不返回模拟.我该如何解决?

But method thenReturn doesn't return a mock. How can I fix it?

推荐答案

您可以执行以下操作:

    @RunWith(PowerMockRunner.class)
    @PrepareForTest(Class.class)
    public class ConnTest {

        @Mock
        private InputStream streamMock;

        private Conn conn;

        @Before
        public void before() {
            initMocks(this);
        }

        @Test
        public void test() {    
            PowerMockito.mockStatic(Class.class);
            PowerMockito.when(Connector.class.getClass().getResourceAsStream("/prop.properties")).thenReturn(streamMock);
            conn = new Conn();
        }

        @After
        public void after() {
            reset(streamMock);
        }
     }

在这里，您将资源放在类对象的顶部，这就是为什么Class.class您需要通过使用@PrepareForTest(Class.class)和PowerMockito.mockStatic(Class.class);准备测试的原因.

Here you are stubbing resource on top of a class object, that is why Class.class you need to prepare for test by using @PrepareForTest(Class.class) and PowerMockito.mockStatic(Class.class);.

我不确定它是否对构造函数有效，但是对于调用getClass.getResourceAsStream("anyString")的方法来说，它工作正常(我已经测试过).

I am not sure whether it'll work for constructor or not but for a method which is calling getClass.getResourceAsStream("anyString") it's working fine(I have tested).

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