How to catch enwrapped exception in Junit test case?

Question

I have a test case as

@Test(expected = IllegalArgumentException.class)
public void test() throws Exception{
  ..test content...
}

Because I'm using Java Reflection in my test case so the IllegalArgumentException is enwrapped in InvocationTargetException, how can I catch expected IllegalArgumentException instead of InvocationTargetException.

Error message shows as

java.lang.Exception: Unexpected exception, expected<java.lang.IllegalArgumentException> but was<java.lang.reflect.InvocationTargetException>
    at org.junit.internal.runners.statements.ExpectException.evaluate(ExpectException.java:28)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)

Problably the answer is already out there, but personally I would simply implement a custom hamcrest matcher that checks for the cause being an IllegalArgumentException - and then use the ExpectedException rule to use it. — Florian Schaetz, Aug 07 '15 at 16:05

score 1 · Accepted Answer · answered Aug 07 '15 at 15:26

1

I don't believe there's a JUnit way of doing it - you probably have to do it manually in the test, e.g.:

@Test
public void test() {
    try {
       runTest();
       fail();
    } catch (InvocationTargetException x) {
       if( ! (x.getCause() instanceof IllegalArgumentException)) {
           fail();
       }
    }
}

answered Aug 07 '15 at 15:26

BarrySW19

3,759
12
26

1

The assertion could be made clearer with `assertTrue( expected.getCause() instanceof IllegalArgumentException );` – Rüdiger Herrmann Aug 07 '15 at 15:29
Ugly a hell. Using an ExpectedException rule (let's call it "expectedException") you could simply write... `expectedException.expect( hasCause( IllegalArgumentException.class ));` by simply implementing a HasCause hamcrest Matcher. – Florian Schaetz Aug 07 '15 at 16:04
1

Well, if you want to go pulling in other libraries then https://code.google.com/p/catch-exception/ is a lot neater still. – BarrySW19 Aug 07 '15 at 16:14
Nice suggestion, like it. – Florian Schaetz Aug 08 '15 at 04:43

How to catch enwrapped exception in Junit test case?

1 Answers1