CODEWITHSUNDEEP
javaunit-testingmockito
Limmy
Limmy

Reputation: 746

Mockito 3+ how to make mockstatic return another plain mock

I'm migrating from PowerMockito&MockitoV2 to Mockito V3+ and trying to rewrite my tests

Previously I had a test which mocker java.sql.DriverManager class static method getConnection(...) to return a plain Mockito.mock(java.sql.Connection.class), now I'm trying to do somethins similar with MockedStatic but can't make static mock return another plain mock, have such error:

org.mockito.exceptions.misusing.WrongTypeOfReturnValue: Connection$MockitoMock$sLucRb7f cannot be returned by getConnection() getConnection() should return Connection *** If you're unsure why you're getting above error read on. Due to the nature of the syntax above problem might occur because:

  1. This exception might occur in wrongly written multi-threaded tests. Please refer to Mockito FAQ on limitations of concurrency testing.
  2. A spy is stubbed using when(spy.foo()).then() syntax. It is safer to stub spies -
    • with doReturn|Throw() family of methods. More in javadocs for Mockito.spy() method.

My test code looks like that:

    @Test
    public void testConnectionIsOk() {
        Connection mockedConnection = Mockito.mock(Connection.class);
        try (MockedStatic<DriverManager> driverManagerMockedStatic = Mockito.mockStatic(DriverManager.class)) {
            driverManagerMockedStatic.when(
                    () -> DriverManager.getConnection(Mockito.anyString(), Mockito.anyString(), Mockito.anyString()))
                    .thenReturn(mockedConnection);
            boolean isConnectionOK = sut.testMethod();

            Assertions.assertTrue(isConnectionOK);
        }
    }

I understand the error is asking me to use a Mockito.doReturn(mockedConnection).when(...) but I can't pass a static method call in that .when(...) block

Is there any workaround for this use case or am I missing anything?

Upvotes: 3

Views: 598

Answers (1)

Feel free
Feel free

Reputation: 1069

You can use thenAnswer instead of thenReturn and just return lambda expression like:

@Test
public void testConnectionIsOk() {
    Connection mockedConnection = Mockito.mock(Connection.class);
    try (MockedStatic<DriverManager> driverManagerMockedStatic = Mockito.mockStatic(DriverManager.class)) {
        driverManagerMockedStatic.when(() -> DriverManager.getConnection(Mockito.anyString(), Mockito.anyString(), Mockito.anyString()))
                .thenAnswer(invocation -> mockedConnection);

        boolean isConnectionOK = sut.testMethod();

        Assertions.assertTrue(isConnectionOK);
    }
}

Upvotes: 2

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