Mocking static functions from other classes in Java using PowerMockito

kaushalpranav

I have written test cases for testing a function in class Main, called functionMain(). I have seen people using PowerMockito to test static functions in the class Main which is under test.

But in my case, functionMain() is using a static function from another class called Branch called staticBranchFunction().

I want to mock staticBranchFunction() inside the tests for the Main class.

This main function actually has calls to static functions from different classes Branch1, Branch2 etc.

Please help.

uli

import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

import static org.junit.Assert.assertEquals;
import static org.mockito.Mockito.when;
import static org.mockito.Mockito.times;
import static org.powermock.api.mockito.PowerMockito.mockStatic;
import static org.powermock.api.mockito.PowerMockito.verifyStatic;

@RunWith(PowerMockRunner.class)
@PrepareForTest({Boom.class})
public class DocTest {

    public String boomWrapper() {
        return Boom.detonate();
    }

    @Test
    public void testBoom() {
        mockStatic(Boom.class);
        when(Boom.detonate()).thenReturn("defused");
        String actual = boomWrapper();
        verifyStatic(Boom.class, times(1));
        Boom.detonate();
        assertEquals("defused", actual);
    }    
}

class Boom {
    private static final String BOOM = "Boom!";  
    public static String detonate() {
        return BOOM;
    }
}

Dependencies:

junit:junit:4.12  
org.mockito:mockito-core:2.13.0  
org.powermock:powermock-module-junit4:2.0.0-beta.5  
org.powermock:powermock-api-mockito2:2.0.0-beta.5

Description:

For more supported versions, please read: Mockito + PowerMock, other supported frameworks Requirements:

List all static classes in @PrepareForTest({Boom.class}) separate by comma.
Mock all static classes by PowerMockito.mockStatic(Boom.class) separate by comma.
use regular mockito methods to setup your expectation, for example Mockito.when(Boom.detonate()).thenReturn("defused")
verify behavior by PowerMockito.verifyStatic(Boom.class, Mockito.times(1)); Boom.detonate(); Important: You need to call PowerMockito.verifyStatic(Boom.class) per method verification.

More details on PowerMock wiki.

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Please contact [email protected] to delete if infringement.

edited at2021-04-29

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