Problem:
I
need to test for a Null or empty string but my test fails with the following
error.

Solution:
Make
sure you use “Should BeNullOrEmpty” and not “Should Be NullOrEmpty”.
Explanation:
When
I originally wrote the test I wrote the assert like this:
$result | Should
Be NullOrEmpty
Which
resulted in the error I showed above.
Removing the space between Be and NullOrEmpty now passes as expected.
$result | Should
BeNullOrEmpty