Add unit tests for API, ParseObject, and ParseUser

[cbaker6]

Items added:

• URLMock - this can be used for mocking any url call or error response
• APICommandTests
• ParseObjectCommandTests
• UserCommandTests
• Modernized URLSession to leverage Result type

This is ready for review...

[cbaker6]

@pranjalsatija I attempted to minimize merge conflicts with #13 by touching little of the code you edited. I know you made a modification to getEncoder, you will see that I had to slightly modify getEncoder by creating another that doesn't skip keys. This was done for testing purposes as I needed something that would act like the parse-server with keys like objectId, createdAt, etc that would encode. You will need to do something similar so we can mock the server in tests

[cbaker6]

@TomWFox @pranjalsatija when you get a chance can you look this over? It’s mostly unit tests verifying that the codebase is working as expected.It also has some minor updates

[pranjalsatija]

Everything looks good except for a few really minor things!

[pranjalsatija]

LGTM! We can touch one or two things up once all the open PRs are merged.

[TomWFox]

@pranjalsatija can you take another look at this and then I can merge?

[cbaker6]

@pranjalsatija the only real changes I made since your last review are the minor ones I made to MockURLProtocol.swift and MockURLResponse.swift, the other SPM files I added, I deleted later as they weren't needed

[pranjalsatija]

LGTM! Sorry about the delay / general unresponsiveness, I'm out of town this week, but I'll be back in action on Friday.

[cbaker6]

@TomWFox no more changes from me on this one

[TomWFox]

Thanks for changing the org name!