无法模拟类，引发异常

Question

    SafeFile safeFile = PowerMockito.mock(SafeFile.class);
    PowerMockito.whenNew(SafeFile.class).withArguments(ApplicationContext.getInstance().getReportsDirectory()).thenReturn(safeFile);
    when(safeFile.getChild(Mockito.any())).thenReturn(safeFile);
    SafeFile result = subsystem.downloadSolution(downloadUrl, path);
    Assert.assertEquals(safeFile, result);
}

    SafeFile downloadSolution(String downloadUrl, String path) throws Exception {
        try {
            String fileName = downloadUrl.substring(downloadUrl.lastIndexOf(SharedConstants.PATH_DELIMITER) + 1, downloadUrl.length());
            SafeFile rootRepoDir = new SafeFile(ApplicationContext.getInstance().getRepositoryDirectory());
            String pkgSolutionPath = "DownloadedSolutions" + SharedConstants.PATH_DELIMITER + path;
            SafeFile tempFile = rootRepoDir.getChild(pkgSolutionPath + fileName);
            if (tempFile.exists()) {
                return tempFile;
            } else {
some logic ...
return new_file;}

java.lang.Exception
    at com.system.subsystems.solutioncentral.SC.downloadSolution(SC.java:1017)
    at com.system.subsystems.solutioncentral.SCTest.testDownloadSolutionFileAlreadyPresentInLocalRepo(SCTest.java:832)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:68)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:326)
    at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:89)
    at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:97)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:310)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper(PowerMockJUnit47RunnerDelegateImpl.java:131)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.access$100(PowerMockJUnit47RunnerDelegateImpl.java:59)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner$TestExecutorStatement.evaluate(PowerMockJUnit47RunnerDelegateImpl.java:147)
    at org.junit.rules.ExpectedException$ExpectedExceptionStatement.evaluate(ExpectedException.java:239)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.evaluateStatement(PowerMockJUnit47RunnerDelegateImpl.java:107)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTest(PowerMockJUnit47RunnerDelegateImpl.java:82)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runBeforesThenTestThenAfters(PowerMockJUnit44RunnerDelegateImpl.java:298)
    at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:87)
    at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:50)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.invokeTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:218)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.runMethods(PowerMockJUnit44RunnerDelegateImpl.java:160)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$1.run(PowerMockJUnit44RunnerDelegateImpl.java:134)
    at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:34)
    at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:44)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.run(PowerMockJUnit44RunnerDelegateImpl.java:136)
    at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:121)
    at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:57)
    at org.powermock.modules.junit4.PowerMockRunner.run(PowerMockRunner.java:59)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)

单元测试以空指针异常退出。SafeFile rootRepoDir的值为null，我不知道为什么。我嘲笑过它，那为什么它显示为null？如果我删除这一行，powerMockito.whennew(Safefile.class).withanyArguments().thenreturn(file1)；则rootRepoDir的值为非空

我在PrepareForTest中添加了sc.class，使用PockerMockRunner运行

Answer 1

您有：

new SafeFile(ApplicationContext.getInstance().getRepositoryDirectory());

还可以在ApplicationContext类上使用MockStatic:

PowerMockito.mockStatic(ApplicationContext.class);
ApplicationContext mockedApplicationContext = Mockito.mock(ApplicationContext.class);

但是，您不对该类执行任何stubbing，所以当您调用applicationcontext.getinstance()时，您将得到默认的返回值NULL。然后尝试调用null.getRepositoryDirectory()，从而调用NPE。

PowerMockito.when(ApplicationContext.getInstance()).thenReturn(appCtxStub);