Full_Coverage_when_Expecting_an_Exception

In JUnit 4 we might write the following:

@Test(expected=RuntimeException.class)
public void methodThatWeExpectAnException() {
    throw new RuntimeException();
}

This test will pass. Yes it’s trivial, of course it would pass. (In reality the single line of code would instead send a message to some object that ultimately would need to generate a RuntimeException for a “real” test to pass.) Fine. That’s not the point.

So what’s the problem with this? Nothing, except that some coverage tools will report the last “line” (the close curly-brace) as not being covered since we did not exit the method cleanly.

Here’s a way to rewrite the above test so that you can assure coverage:

@Test
public void methodThatWeExpectWillThrowAnException() {
    boolean expectedThrown = false;

    try {
        throw new RuntimeException();
    } catch (RuntimeException e) {
        expectedThrown = true;
    }

    assertTrue(expectedThrown);
}

This version is a bit longer, isn’t it?

Here are some comments I’d like to hear from you:

Is it any better?
Does is express our intent any better?
Isn’t it just silly to run coverage tools on your test code?
Is anybody having Pascal flashbacks? (If you don’t get this question…you poor &*$^@~).

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