Few days ago, I come across to a bunch of tests that were using the null conditional operator in the wrong way and I think it is worth sharing it.
Have a look at this code and how I fixed it.
What's the problem with the original code?
When result is null, the test pass even if clearly shouldn't!
The reason is because of the "short-circuiting" behaviour.
When result is null, then the rest of the chain’s execution stops! The test then pass because the method ends and by default a test without assertions is a pass.
You can learn more about "short-circuiting" with null conditional operators here.
How did I fix it?
In this particular case I have just removed the null conditional operator and performed a simple comparison using equality instead of relying on calling ToString.
So...
Be careful when using null conditional operators in assertions and remember about "short-circuiting".