我有一个函数返回一个异常,现在我要在Junit4中编写一个单元测试用例。问题是,reflect.invoke总是将异常包装在InvocationTargetException中,因此无法使用ExpectedException类检查异常。
public class Hello {
private void printHello(String msg) {
if ("hello".equals(msg)) {
System.out.println("Hello");
}
else throw new HeaderException();
}
}
测试:
@Rule
public ExpectedException expectedEx = ExpectedException.none();
@Test
public void testPrint() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
expectedEx.expect(HeaderException.class);
Method method = Hello.class.getDeclaredMethod("printHello", String.class);
method.setAccessible(true);
method.invoke(Hello.class,"random");
}
输出:
java.lang.AssertionError:
Expected: an instance of com.locationguru.CSF.exception.HeaderException
got: <java.lang.reflect.InvocationTargetException>
<Click to see difference>
at org.junit.Assert.assertThat(Assert.java:780)
at org.junit.Assert.assertThat(Assert.java:738)
at org.junit.rules.ExpectedException$ExpectedExceptionStatement.evaluate(ExpectedException.java:114)
at org.junit.rules.RunRules.evaluate(RunRules.java:18)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:78)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:212)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:68)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
expectedEx.expectCause(instanceOf(HeaderException.class));
就可以了,但不幸的是 HeaderException 并没有存储在cause
中,而是存储在target
中。我建议你编写自己的 Matcher 或在网络上搜索通用的 ExceptionMatcher。 - CoronA