如何获得具有nunit约束的格式正确的测试结果

Question

My custom constraint collects messages about expected values and actual values. They are written to the 'MessageWriter' by overriding 'WriteDescriptionTo':

    public override void WriteDescriptionTo(MessageWriter writer)
    {
        writer.WriteExpectedValue(_expectedMessages);
        writer.WriteActualValue(_actualMessages);
    }

But in the test results all information is in the expected result:

Expected: < On item 2 expected: Expected Reversible: True <> On item 2 actual: Actual Reversible: False > But was: <UNSET>

NOTE: I fail in formatting the text here, it refuses to use respect my newlines. So here's a screenshot of the result text:

The "But was:" part remains <UNSET>

So how to get the actual text to the right spot?

It's not a huge problem, just really annoying that I seem to be using the right method but it won't work, even seems like a bug in nunit.

Answer 1

Okay, I checked the source of NUnit. The actual line is always generated by the framework, whether or not you called WriteActualValue before.

Instead you should set the actual field of your custom constraint (inherited from Constraint ) to your _actualMessages stuff (or you refactor your code to live without _actualMessages at all). This should bring your expected output.