Brent/backend65 listing endpoints

[bmachado18]

Description

Implemented each API's testing and functionality for listing microservice. This firstly involved configuring Cypress to the correct directory structure, then repeatedly writing tests equivalence class tests for an unimplemented API route, and after implementing the route until the tests pass. These endpoints defined within the swagger UI under listings, and within the API list in the SRS doc.

An additional module installed was pg-promise with the command npm install pg-promise

Keeping as a draft PR until all routes have implementations and tests.

• [x] GET /api/listing/{id}
• [x] POST /api/listing
• [x] DELETE /api/listing/{id}
• [x] PATCH /api/listing/{id}

Concerns:

• In the API Agreement, GET listing includes the reviews of the listing, including the review information. Is that really necessary for every listing, or should it just return a list of review_id's attached to the listing? YES, since this api is mainly used by frontend and they user info need it on the listing page.
• In the API Agreement, GET listing does not have a comment/message describing the error. Should this be updated?
• in API Agreement, the post listing (Create) returns the newly created data. This violates REST principles, a POST should create and a GET should retrieve, right? So the POST should just return a message indicating success or not.

Closes #65

How to Test

There might be a better way to do this, but:

1. Remove all docker images, and build the following images:

   
   docker-compose down

docker-compose up --build -d listing database datalayer

3. Go into exec of the listing service within docker, and the test suite:

![image](https://github.com/UVicMartletplace/martletplace/assets/65056763/6d893ef5-2537-44d5-8a55-faa43d365a0f)

```npm test```

## Checklist
- [ ] The code includes tests if relevant
- [ ] I have *actually* self-reviewed my changes and done QA
<!-- Only check this off if you have actually done a self-review! DO NOT request any review from others until you have done your self-review! -->

[bmachado18]

@UVicMartletplace/backend I added a new route for the GET /api/listings/{id} but since I am new to node and express I was hoping you could review this first route so I can reduce changes for the other routes if done incorrectly or if the file structure or directory is off.

I still need to parse the data to the response specified in the API Agreement (and its tests accordingly) but otherwise please leave a comment and let me make the changes!

ALSO take a look at the concerns section of this draft PR and maybe we can chat about them.

THANKS!

[bmachado18]

Implemented each route as specified in the API spec. Other notes:

• We gave up on Jest due to transpilation errors; instead we are using Cypress. Currently these tests are mainly integration between database and listing service. I tried to use mocha and chai for unit tests and mocking but went into a rabbithole and gave up on that.
• In the database, added a distance attribute for listing; we talked about this not being used, in the past, and currently the createListing/updateListing API doesn't support modifying this distance, but it was needed so it complies with the listing GET request from the API spec. UPDATE: removed, now calculating distance.
• CI is not working - I tried installing all the dependencies for cypress in the listings dockerfile, but then I get another error (see these tests for details). I didn't want to get to deep into it. UPDATE: got this working.
• Auth is still not supported, so left a comment and we can make a new PR when it works.
• added the ON delete cascade for listing_id for messages/reviews/user_prefs tables as a quick fix for contraint violations - we might want to change this in the future but it works for now.

[bmachado18]

@MNThomson I understand you guys are getting graded on our tests - I dumped alot of time already trying to configure unit testing with mocha and chai alongside integration tests for cypress. We don't have any true unit tests so I can dump some more time to try and figure this out if you'd like.