Create unit tests for users.router.js and move integration tests

[dannyprikaz]

Fixes #1881

What changes did you make and why did you make them ?

• Moved tests for users.router.js to backend/test/ directory
• Wrote unit tests for users.router.js that isolate the behavior of the router from its dependencies

[dannyprikaz]

Want to review this pull request? Take a look at this documentation for a step by step guide!

From your project repository, check out a new branch and test the changes.

git checkout -b dannyprikaz-1881-users-router-unit-tests
git pull https://github.com/dannyprikaz/VRMS.git 1881-users-router-unit-tests

[JackHaeg]

@jng34 Given that you are also working on unit tests issues, we would love for you to take a crack at reviewing this PR from @dannyprikaz!

[jng34]

@dannyprikaz All unit tests passed. Great use of comments and good template for writing future tests!

[JackHaeg]

@dannyprikaz given that we have @jng34 approval, please feel free to go ahead and merge this PR whenever you have a moment. Would love for you to get the GitHub credit for this one!

[dannyprikaz]

Hey, @jng34

I figured out how to test specific expectations of request bodies and url parameters that are passed to controller methods. This should make our tests more complete. Could you please review this one more time. I'm going to include the technique that I learned on PRs that I'm reviewing from you.

[jng34]

@dannyprikaz
The changes are definitely more complete now, given that you're now able to parse the incoming data. Great work!

[jng34]

@JackHaeg
I forget, should I merge the pull request or wait for a 2nd reviewer for this?