Add unit/e2e tests for mongo-typeorm sample

[kiwikern]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[x] Other... Please describe: Docs / Samples

What is the current behavior?

Issue Number: #1539

What is the new behavior?

Added unit + e2e tests for mongo+typeorm sample.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[coveralls]

Pull Request Test Coverage Report for Build c6f66b77-4cf5-4dc2-a4bc-d25738b16a38

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 94.818%

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Totals
Change from base Build 736a64e8-08de-40ee-9990-faac31009973:	0.0%
Covered Lines:	4922
Relevant Lines:	5191

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💛 - Coveralls

[BrunnerLivio]

Thanks a lot for your PR @kiwikern !
Could you rebase with master - we run sample e2e & unit tests now in CI :)

@kamilmysliwiec how shall we run the e2e tests with the database in CI? Either we use

• SQLite so we would not need a docker-compose file?
• We run docker-compose up && jest --config ./test/jest-e2e.json as npm run test:e2e script?
• Update the test:e2e:samples task to make it work with docker-compose out of the box?

[kamilmysliwiec]

Update the test:e2e:samples task to make it work with docker-compose out of the box?

How would that look like?

[BrunnerLivio]

@kamilmysliwiec Check whether the sample has a docker-compose.yml file in the root directory and run docker-compose up -d if so.

[kiwikern]

Thanks for your feedback @BrunnerLivio. 🙂 I addressed your comments and rebased to master. As expected, the e2e test is now failing since the database is not started.

[kamilmysliwiec]

Since the only thing the controller does is delegating work to the injected service instance (which we mock in this test), it doesn't really bring any value (does not protect us from anything).

[kiwikern]

@kamilmysliwiec I absolutely agree that these tests do not ensure the example code does not break. However, I believe the goal of the tests is to rather serve as examples on how to set up unit/e2e tests for the mongo-sample given. Especially, how you can mock a repository can be of interest for new users.

From the linked issue #1539:

Give new users like me simple and practical examples for implementing tests