How do I configure PowerMock to use Mockito's mock-maker-inline feature

Step 1: Understand the Basics

- PowerMock and Mockito Compatibility: Ensure that your versions of PowerMock and Mockito are compatible. PowerMock version 2.0.0 and above supports Mockito 2, but there might be some compatibility issues with certain features[1].

- Mockito Inline Mock Maker: This feature allows mocking of final classes and methods. It was introduced in Mockito 2.1.0 and requires a Java agent for instrumentation[4].

Step 2: Configure Mockito Inline Mock Maker

To enable Mockito's `mock-maker-inline`, you need to create a specific configuration file:

1. Create the Configuration File:
- Navigate to your project's `src/test/resources` directory.
- Create a directory named `mockito-extensions` if it doesn't exist.
- Inside `mockito-extensions`, create a file named `org.mockito.plugins.MockMaker`.
- Add the following line to this file: `mock-maker-inline`[2].

Step 3: Configure PowerMock

PowerMock can interfere with Mockito's `mock-maker-inline` due to its own `MockMaker`. To resolve this, you need to configure PowerMock to delegate to Mockito's `mock-maker-inline`:

1. Configure PowerMock's MockMaker:
- Create a file named `powermock-configuration.properties` in the `org/powermock/extensions` directory under your project's resources.
- Add the following line to this file: `mockito.mock-maker-class=mock-maker-inline`[1].

Step 4: Use PowerMock with Mockito

To use PowerMock with Mockito in your tests, ensure you have the correct annotations:

1. Annotations:
- Annotate your test class with `@RunWith(PowerMockRunner.class)`.
- Use `@PrepareForTest` to specify the classes that you want to mock static methods for[3].

Example

Here's a simple example of how you might use PowerMock with Mockito's inline mock maker:

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

import static org.mockito.Mockito.verify;

@RunWith(PowerMockRunner.class)
@PrepareForTest(YourClassToMock.class)
public class YourTest {

    @Test
    public void testYourMethod() {
        // Mocking static methods or final classes using PowerMockito
        PowerMockito.mockStatic(YourClassToMock.class);
        
        // Your test logic here
        
        // Verify interactions
        verifyStatic(YourClassToMock.class);
    }
}

Important Notes

- Classloader Issues: There might be classloader issues when using both PowerMock and Mockito's `mock-maker-inline` in the same project. Ensure that you handle these issues by configuring PowerMock correctly[6].
- Java Agent Dependency: Mockito's inline mock maker requires a Java agent for instrumentation. Ensure that you have the necessary dependencies in your project[8].