NoSuchElementException from CompareMatcher#describeTo(Description)

[chludwig-haufe]

One of our integration tests fails with a NoSuchElementException escaping from CompareMatcher#describeTo(Description). We use org.xmlunit:xmlunit-matchers:2.5.0.

In the debugger, I can see that the matcher's diffResult is != null, but diffResult.hasDifferences() == false. Since describeTo(Description) only checks for diffResult == null, the code flow enters ComparisonMatcher#firstComparison() where the subexpression diffResult.getDifferences().iterator().next() throws the NoSuchElementException.

The fix seems easy: Simply test for diffResult == null || !diffResult.hasDifferences() at the beginning of CompareMatcher#describeTo(Description).

[bodewig]

Thanks a lot.

Given this hasn't come up before it seems describeTo usually isn't invoked if matches returns true, I wonder what you are doing to trigger this. :-)

Nevertheless this certainly is a bug. It's fixed on a branch of which I intend to cut 2.5.1 during the weekend.

[chludwig-haufe]

Thanks.

Since you wondered: I encountered the bug in a rest-assured body check that calls a hierarchy of delegating matchers:

// ...
 .body(isDocumentFrom(getRequestTarget())
                .thatMatches(
                    allOf(
                        metadataIsEqualTo(expectedMetaElement),
                        baselineContent(isSimilarTo(baselineControl)),
                        nativeContent(isSimilarTo(nativeControl)))));

[bodewig]

Thank you. This is a slightly different incarnation of #81 - sorry for not catching the problem back then.

I've published new 2.5.1-SNAPSHOT artifacts if you need the fix before the weekend.

[bodewig]

carved out some time today, 2.5.1 has just been released, I'll officially announce it later.

[chludwig-haufe]

Great, thanks a lot!