Unit Tests failing when I Run All Tests but pass when I Debug

c# visual-studio unit-testing nunit nunit-3.0
Michael Hennigan picture Michael Hennigan · May 13, 2017 · Viewed 11.2k times · Source

I'm using NUnit3 in Visual Studio 2017 and doing TDD. Something really strange is happening since I updated my code to make my latest test pass.

Now, 3 of my other tests are failing when I click Run All Tests, as below:

enter image description here

It is telling me that the actual and expected values in my Assert method are not equal.

However, when I put a breakpoint at the line where the Assert method is and start debugging, the stacktrace is showing that expected and actual are the same value and then the test passes, as below:

enter image description here

Am I doing something stupid or could there be a bug in VS2017 or NUnit or something?

This ever happen to anyone else?

[Edit: I should probably add that I have written each test as a separate class]

Answer

Nkosi picture Nkosi · May 14, 2017

The failing tests share a resource that affects them all when tested together. Recheck the affected tests and their subjects.

You should also look into static fields or properties in the subjects. They tends to cause issues if not used properly when designing your classes.

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