使用 PowerMock 模拟私有方法,但仍会调用底层方法
我正在尝试模拟一个进行 JNDI 调用的私有方法.当从单元测试中调用该方法时,它会引发异常^.我想模拟该方法以进行测试.我使用了 来自另一个问题的示例代码回答,当测试通过时,似乎仍然调用了底层方法.我在 doTheGamble()
方法中插入了一个 System.err.println()
,它被打印到我的控制台.
I am trying to mock out a private method that is making a JNDI call. When that method gets called from a unit test, it throws an exception^. I would like to mock-out that method for testing purposes. I used the sample code from another questions answer, and while the test passes, it seems that the underlying method still gets called. I inserted a System.err.println()
in the doTheGamble()
method, and it gets printed out to my console.
很有趣,如果我注释掉第一个 assertThat
,测试就通过了.?:(
Interesting enough, if I comment out the first assertThat
, the test passes. ?:(
那么,我如何模拟一个私有方法以使其不被调用?
So, how do I mock out a private method so that it does not get called?
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( "
>>> GAMBLE CALLED <<<
" );
PowerMock_Test.gambleCalled = true;
return gamble;
}
}
^可以理解,因为我的工作区不支持JNDI,所以只有生产环境支持
^ understandably, since my workspace does not support JNDI, only the production environment does
% 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.
% I am using the latest versions of all the library, JUnit 4.10, Mockito 1.8.5, Hamcrest 1.1, Javassist 3.15.0, and PowerMock 1.4.10.
推荐答案
来自 PowerMock 私有方法示例:
@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");
}
所以要将它应用到您的代码中,我认为它可能会变成:
So to apply this to your code, I think it might become:
@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());
}
}
我只是在此处的编辑器中编写了代码.没有实际运行任何测试,并且在编写此代码时没有任何错误受到损害.
I just coded that in the editor here. No tests have actually been run, and no bugs have been harmed in the crafting of this code.
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