Replace unit test assertions with Gomega matchers

[bjee19]

Proposed changes

Problem: There were still some existing unit tests that weren't using the Gomega matcher library for assertions.

Solution: Changed existing tests to use the Gomega matcher library. In addition, I replaced the deprecated NewGomegaWithT with NewWithT.

Testing: Unit tests still pass

Closes #823

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

[bjee19]

There are a couple of situations where Fatal/Fatalf is used and I wasn't sure if I should change that to a Gomega assertion. Fatal/Fatalf logs a message then calls FailNow which marks the function as failed and stops its execution by calling runtime.Goexit and I wasn't sure how to replicate this behavior using Gomega assertions. Is it fine to leave these situations as is?

[kate-osborn]

There are a couple of situations where Fatal/Fatalf is used and I wasn't sure if I should change that to a Gomega assertion. Fatal/Fatalf logs a message then calls FailNow which marks the function as failed and stops its execution by calling runtime.Goexit and I wasn't sure how to replicate this behavior using Gomega assertions. Is it fine to leave these situations as is?

You can change those instances to a gomega assertion. The test will fail and stop executing on the first failed gomega assertion.