如何通过 EasyMockRule 或 EasyMockRunner 委托使用 EasyMockSupport？

Question

通过委托（而不是继承）使用EasyMockSupport时，是否可以同时利用EasyMockSupport和EasyMockRule（或EasyMockRunner）？

换句话说：如何让EasyMockSupport 知道EasyMockRule 创建的模拟？

这是一个 MWE，展示了我面临的问题：

// Class under test
public class MyClass {
    private Collaborator collaborator;
    public MyClass() {
        collaborator = new Collaborator();
    }

    // Method under test
    public int myMethod() {
        return collaborator.mockedMethod() + 1;
    }
}

// Class to be mocked
public class Collaborator {
    public int mockedMethod() {
        return 1;
    }
}

// Test case
public class MyClassTest {
    private EasyMockSupport easyMockSupport = new EasyMockSupport();
    @Rule public EasyMockRule easyMockRule = new EasyMockRule(this);

    @TestSubject private MyClass testSubject = new MyClass();
    @Mock private Collaborator collaboratorMock;

    @Test public void testMyMethod() {
        EasyMock.expect(collaboratorMock.mockedMethod()).andReturn(2);
        easyMockSupport.replayAll();

        int result = testSubject.myMethod();
        Assert.assertEquals("Should return 2+1 when successfully mocked", 3, result);
        // throws java.lang.AssertionError: expected: <3> but was: <1>
    }
}

测试失败，但如果MyClassTest 扩展EasyMockSupport，则测试通过。 （但我不能将继承用于我正在做的事情，因此我的问题。）

我对这种行为的理解是，在我的示例中，EasyMockSupport 不知道 Collaborator 模拟，因此调用 replayAll() 无效，并且在 @987654337 中调用模拟仍处于记录状态@（因此 mockedMethod() 返回 0）。 确实，injectMocks() documentation 说：

如果参数扩展了 EasyMockSupport，将使用它创建模拟，以允许 replayAll/verifyAll 之后工作

但是当使用委托时，参数（即测试类）不会扩展EasyMockSupport。有什么我遗漏的还是不可能的？

旁注：我使用的是 EasyMock 3.6。理想情况下，我想找到一个保留该版本的解决方案，但请随时指出在以后的版本中是否有相关的功能/错误修复。

提前感谢您的帮助！

Answer 1

不容易。不过这是一个有用的用例，所以我建议您填写issue。

同时，我们需要让规则知道 EasyMocksSupport。这是一个解决方案。

import org.easymock.EasyMock;
import org.easymock.EasyMockRule;
import org.easymock.EasyMockSupport;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.easymock.internal.MocksControl;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;

import java.lang.reflect.Field;

// Class under test
class MyClass {
    private Collaborator collaborator;
    public MyClass() {
        collaborator = new Collaborator();
    }

    // Method under test
    public int myMethod() {
        return collaborator.mockedMethod() + 1;
    }
}

// Class to be mocked
class Collaborator {
    public int mockedMethod() {
        return 1;
    }
}

class ExtendedEasyMockSupport extends EasyMockSupport {
    public void addMock(Object mock) {
        if(EasyMockSupport.getMockedClass(mock) == null)  {
            throw new IllegalArgumentException(mock + " is not a mock");
        }
        MocksControl control = MocksControl.getControl(mock);
        controls.add(control);
    }

    public void addAllMocks(Object testClass) {
        Field[] fields = testClass.getClass().getDeclaredFields();
        for (Field field : fields) {
            Mock annotation = field.getAnnotation(Mock.class);
            if(annotation != null) {
                field.setAccessible(true);
                Object mock;
                try {
                    mock = field.get(testClass);
                } catch (IllegalAccessException e) {
                    throw new RuntimeException(e);
                }
                addMock(mock);
            }
        }
    }
}

// Test case
public class MyClassTest {
    private final ExtendedEasyMockSupport easyMockSupport = new ExtendedEasyMockSupport();
    @Rule
    public EasyMockRule easyMockRule = new EasyMockRule(this);

    @TestSubject
    private final MyClass testSubject = new MyClass();

    @Mock
    private Collaborator collaboratorMock;

    @Before
    public void before() {
        easyMockSupport.addAllMocks(this);
    }

    @Test
    public void testMyMethod() {
        EasyMock.expect(collaboratorMock.mockedMethod()).andReturn(2);
        easyMockSupport.replayAll();

        int result = testSubject.myMethod();
        Assert.assertEquals("Should return 2+1 when successfully mocked", 3, result);
        // throws java.lang.AssertionError: expected: <3> but was: <1>
    }
}