Expecting Exceptions with JUnit doesn't work

Question

I wrote a JUnit test for my method.
This is my method:

 public static int delimit(int value, int min, int max) throws IllegalArgumentException { if (min > max) throw new IllegalArgumentException("Min value was greater than max value."); return Math.min(max, Math.max(min, value)); }

This is the test:

 public class DMathTest extends TestCase { @Rule public ExpectedException exception = ExpectedException.none(); @Test public void testDelimit() { ... exception.expect(IllegalArgumentException.class); DMath.delimit(1, 3, 2); } }

The IllegalArgumentException is indeed thrown, but JUnit marks it as an error in the test. It tells me that the test failed, because of the (expected) exception. There is no AssertionError or anything, it just shows my IllegalArgumentException, as if the whole expectation code wasn't there. I then removed the rule and all the expectation code and it was exactly the same result (of course, this is how it should be). So the rule and the call

exception.expect(IllegalArgumentException.class);

didn't do anything.
I am using Eclipse and I include JUnit using Maven. The dependency element looks like this:

<dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency>

What did I do wrong? Why is the expecting of the exception not working?

Sean Patrick Floyd · Accepted Answer · 2017-03-06 10:02:52Z

public class DMathTest extends TestCase { ^^^^^^^^^^^^^^^^

This may be the error. TestCase is the JUnit 3.x API. JUnit 4.x tests no longer extend that class, and perhaps the semantics change by extending it. Please remove the extends clause and try again, because otherwise, your code looks right.

Also, in JUnit 4.x, you are no longer required to use the "testXyz" naming convention. The method name can be anything, as long as the method is public and annotated with @Test. I usually go with a "should" method name, e.g. "delimitShouldFailIfMinGtMax". That makes for much more readable test reports.

Yes, that was the mistake. Without extending TestCase it works fine. Thank you very much!

Collectives™ on Stack Overflow

Expecting Exceptions with JUnit doesn't work

1 Answer 1

1 Comment

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Related