使用PowerMock模拟私有方法，但底层方法仍然被调用

java junit mockito powermock

2022-09-01 11:58:55

我试图模拟一个进行JNDI调用的私有方法。当从单元测试调用该方法时，它会引发异常^。出于测试目的，我想模拟这种方法。我使用了另一个问题答案中的示例代码，当测试通过时，似乎仍然调用了基础方法。我在方法中插入了一个，它被打印出来到我的控制台上。System.err.println()doTheGamble()

有趣的是，如果我注释掉第一个，测试通过。?:(assertThat

那么，我如何模拟一个私有方法，以便它不会被调用？

import static org.hamcrest.core.Is.is;
import static org.junit.Assert.assertThat;
import static org.mockito.Matchers.anyInt;
import static org.mockito.Matchers.anyString;
import static org.powermock.api.mockito.PowerMockito.when;
import static org.powermock.api.support.membermodification.MemberMatcher.method;

import java.util.Random;

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;

@RunWith(PowerMockRunner.class)
@PrepareForTest(CodeWithPrivateMethod.class)
public class PowerMock_Test {

    static boolean gambleCalled = false; 

    @Test(expected = RuntimeException.class)
    public void when_gambling_is_true_then_always_explode() throws Exception {
        CodeWithPrivateMethod spy = PowerMockito.spy(new CodeWithPrivateMethod());

        when(spy, method(CodeWithPrivateMethod.class, "doTheGamble", String.class, int.class))
                .withArguments(anyString(), anyInt())
                .thenReturn(true);

/* 1 */ assertThat( PowerMock_Test.gambleCalled, is(false) );
        spy.meaningfulPublicApi();
/* 2 */ assertThat( PowerMock_Test.gambleCalled, is(false) );
    }
}


class CodeWithPrivateMethod {

    public void meaningfulPublicApi() {
        if (doTheGamble("Whatever", 1 << 3)) {
            throw new RuntimeException("boom");
        }
    }

    private boolean doTheGamble(String whatever, int binary) {
        Random random = new Random(System.nanoTime());
        boolean gamble = random.nextBoolean();

        System.err.println( "\n>>> GAMBLE CALLED <<<\n" );
        PowerMock_Test.gambleCalled = true;

        return gamble;
    }
}

^ 可以理解的是，由于我的工作区不支持 JNDI，因此只有生产环境支持 JNDI

% 我正在使用所有库的最新版本，JUnit 4.10，Mockito 1.8.5，Hamcrest 1.1，Javassist 3.15.0和PowerMock 1.4.10。

答案 1

从 PowerMock 私有方法示例中：

@RunWith(PowerMockRunner.class)
// We prepare PartialMockClass for test because it's final or we need to mock private or static methods
@PrepareForTest(PartialMockClass.class)
public class YourTestCase {
@Test
public void privatePartialMockingWithPowerMock() {        
    PartialMockClass classUnderTest = PowerMockito.spy(new PartialMockClass());

    // use PowerMockito to set up your expectation
    PowerMockito.doReturn(value).when(classUnderTest, "methodToMock", "parameter1");

    // execute your test
    classUnderTest.execute();

    // Use PowerMockito.verify() to verify result
    PowerMockito.verifyPrivate(classUnderTest, times(2)).invoke("methodToMock", "parameter1");
}

因此，要将此应用于您的代码，我认为它可能会变成：

@RunWith(PowerMockRunner.class)
@PrepareForTest(CodeWithPrivateMethod.class)
public class PowerMock_Test {
    @Test(expected = RuntimeException.class)
    public void when_gambling_is_true_then_always_explode() throws Exception {
        CodeWithPrivateMethod spy = PowerMockito.spy(new CodeWithPrivateMethod());

        PowerMockito.doReturn(true).when(spy, "doTheGamble", anyString(), anyInt());


/* 1 */ PowerMockito.verifyPrivate(spy, times(0)).invoke("doTheGamble", anyString(), anyInt());            
        spy.meaningfulPublicApi();
/* 2 */ PowerMockito.verifyPrivate(spy, times(2)).invoke("doTheGamble", anyString(), anyInt());            
    }
}

我刚刚在编辑器中对此进行了编码。实际上没有运行任何测试，并且在制作此代码时没有损坏任何错误。

答案 2

艺术B，

只需粘贴完整的代码，在我的Eclipse IDE中工作正常。我只是改变了我在上一篇文章中所说的期望。祝你好运。

import static org.hamcrest.core.Is.is;
import static org.junit.Assert.assertThat;
import static org.mockito.Matchers.anyInt;
import static org.mockito.Matchers.anyString;
import static org.powermock.api.support.membermodification.MemberMatcher.method;

import java.util.Random;

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;

@RunWith(PowerMockRunner.class)
@PrepareForTest(CodeWithPrivateMethod.class)
public class PowerMock_Test {

    static boolean gambleCalled = false; 

    @Test(expected = RuntimeException.class)
    public void when_gambling_is_true_then_always_explode() throws Exception {
        CodeWithPrivateMethod spy = PowerMockito.spy(new CodeWithPrivateMethod());

//        PowerMockito.doReturn(true).when(spy, "doTheGamble", anyString(), anyInt());

        PowerMockito.doReturn(true).when(spy, 
               method(CodeWithPrivateMethod.class, "doTheGamble", String.class, int.class))
                .withArguments(anyString(), anyInt());

        assertThat( PowerMock_Test.gambleCalled, is(false) );
        spy.meaningfulPublicApi();
        assertThat( PowerMock_Test.gambleCalled, is(false) );
    }
}


class CodeWithPrivateMethod {

    public void meaningfulPublicApi() {
        if (doTheGamble("Whatever", 1 << 3)) {
            throw new RuntimeException("boom");
        }
    }

    private boolean doTheGamble(String whatever, int binary) {
        Random random = new Random(System.nanoTime());
        boolean gamble = random.nextBoolean();

        System.err.println( "\n>>> GAMBLE CALLED <<<\n" );
        PowerMock_Test.gambleCalled = true;

        return gamble;
    }
}