JUnit AssertionError-未引发预期异常

Question

public FSDataInputStream getObj(String hName, Path p) throws IOException {

    String myKey = pathToKey(hName, p);
    FileStatus status = memoryCache.getStatus(p.toString());
    if (status == null) {
      status = getStatus(hName, p, "getObj");
    }
    if (status.isDirectory()) {
        throw new FileNotFoundException("Can't open " + path
  + " because it is a directory");
    }
    InputStream inputStream = new InputStream(bucket, myKey,
    status.getLen(), client, readAhead, inputPolicy);

    return new FSDataInputStream(inputStream);
}

public class ClientTest {
    MemoryCache memoryCache = mock(MemoryCache.class);
    FileStatus fileStatus = mock(FileStatus.class);

    @Rule
    public final ExpectedException exception = ExpectedException.none();

    @Test
    public void getObjTest() throws Exception {
        Path path = new Path("xyz://aa-bb-cc/data7-1-23-a.txt");

        when(memoryCache.getFileStatus(path.toString())).thenReturn(fileStatus);
        when(fileStatus.isDirectory()).thenReturn(true);
        exception.expect(FileNotFoundException.class);
    }
}

java.lang.AssertionError：预期测试将在org.junit.Assert.Fail(Assert.java:88)在org.junit.rules.ExpectedException.FailduetOmissingException(ExpectedException.java:263)在org.junit.rules.ExpectedException.Access$200(ExpectedException.java:106)在org.junit.rules.ExpectedException.Java:245)在ckjunit47runnerdelegateimpl.java:91)在org.powermock.modules.junit4.internal.impl.powermockjunit44runnerdelegateimpl.$powermockjunit44methodrunner.runbeforesthentesthenafters(powermockjunit44runnerdelegateimpl.java:282)在org.junit.internal.runners.methodroadie.runtest(methodroadie.java:87)在莫ckjunit44runnerdelegateimpl.java:207)在org.powermock.modules.junit4.internal.impl.powermockjunit44runnerdelegateimpl.runmethods(powermockjunit44runnerdelegateimpl.java:146)在org.powermock.modules.junit4.internal.impl.powermockjunit44runnerdelegateimpl.java:146)在.modules.junit4.internal.impl.powermockJunit44RunnerDelegateImpl.run(powermockJunit44RunnerDelegateImpl.java:122)在org.powermock.modules.junit4.common.internal.impl.junit4TestSuiteChunkerImpl.run(junit4TestSuiteChunkerImpl.java:106)在4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)在org.eclipse.jdt.internal.junit.runner.testExecution.run（testExecution.java:38)在org.eclipse.jdt.internal.junit.runner.remotetestrunner.runtest（remotetestrunner.java:459)在org.eclipse.jdt.internal.junit.runner.remotetestrunner.java:678)在.java：192）

有人能告诉我什么地方做错了吗？

Answer 1

方法getobj必须在类中声明（我们在OP中看不到这一点），但让我们假设它在这个类中：

public class Foo {
    private MemoryCache memoryCache;

    public Foo(MemoryCache memoryCache) {
        this.memoryCache = memoryCache;
    }

    public FSDataInputStream getObj(String hName, Path p) throws IOException {
        // ...
    }
} 

现在，您的测试可以如下所示：

public class ClientTest {
    private MemoryCache memoryCache = mock(MemoryCache.class);
    private FileStatus fileStatus = mock(FileStatus.class);

    @Rule
    public final ExpectedException exception = ExpectedException.none();

    @Test
    public void getObjTest() throws Exception {
        Path path = new Path("xyz://aa-bb-cc/data7-1-23-a.txt");

        // create the class-under-test, supplying the mocked MemoryCache
        Foo foo = new Foo(memoryCache);

        // establish your expectations on the mocked classes
        // for this test the expectations are:
        // - memoryCache returns the mocked fileStatus    
        // - the mocked fileStatus 'is a' directory        
        when(memoryCache.getFileStatus(path.toString())).thenReturn(fileStatus);
        when(fileStatus.isDirectory()).thenReturn(true);

        // you expect a FileNotFoundExceptionException ...
        exception.expect(FileNotFoundException.class);

        // ... when you invoke getObj
        foo.getObj("aString", path);
    }
}

备注：

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