Closed Issue: NpmTests test discoverer warnings [519]

Output Window/Tests
```
------ Discover test started ------
UTA005: Illegal use of attributes on NpmTests.AbstractFilesystemPackageJsonTests.Init.The TestInitializeAttribute can be defined only inside a class marked with the TestClass attribute.
UTA006: Illegal use of attributes on NpmTests.AbstractFilesystemPackageJsonTests.Cleanup. The TestCleanupAttribute can be defined only inside a class marked with the TestClass attribute.
========== Discover test finished: 373 found (0:00:05.6439006) ==========
```