Add database test for SubscriptionManager

[SydneyDrone]

What is it?

• Codebase improvement (dev facing)

Description of the changes in your PR

• A JUnit test file is added to test SubscriptionManager.kt (see New streams notifications #2335). However, the test result shows that either the original methods or my understanding of those methods has some problem, so I made this a draft.
• The first problem is that the ChannelInfo I insert doesn't equal to the one I searched. The test result shows that it's because of their difference in the uid. IDK if it is designed to operate like that. If it is, I will delete the corresponding test cases in later commit.
• The second problem is that the updateNotificationMode() method doesn't seems to function correctly. The testUpdateNotificationMode() method 2 and 4 seems to be problematic and redundant, but I will temporarily keep them until this problem is solved or clairfied.
• The third problem is that the rememberAllStreams() method doesn't seems to fetch all videos as it should be (in my test case, it just fetched two instead of the total number of 100+)

Before/After Screenshots/Screen Record

• The total test result:
  

Fixes the following issue(s)

• Fixes Add more tests for methods involving the database #8080
• Related to Only one empty playlist is shown #2758

Due diligence

• I read the contribution guidelines.

[opusforlife2]

Are you adding all possible tests that involve the database? If not, then I don't think you should link this PR to that issue. This would then be one of several PRs that work towards completion of the objective stated there.

[opusforlife2]

@SydneyDrone Please try to provide a reason when you close a PR. It helps when we're looking at it in the future.

[Stypox]

@SydneyDrone thank you for writing these tests, I think they are valid. Could you reopen?

[SydneyDrone]

@SydneyDrone thank you for writing these tests, I think they are valid. Could you reopen?

It's reopened now. Sorry for the inconvenience.

[Stypox]

I made some changes:

• fix checkstyle errors
• tests do not run in order, so each one has to do its own assertions separately from what others did
• the uid of an entity in the database needn't be the same of the one created in-memory, since the uid gets assigned upon inserting in the database
• some database functions return a Completable that doesn't do anything until it is subscribed to or awaited, so I added .awaitBlocking() where needed
• the data of an entity in-memory does not get updated automatically when the corresponding entity in the database is changed, so some tests have been removed
• manager.insertSubscription only inserts recent streams, so they need to have a date set on them (I also made related items hardcoded and not dependent on what the channel is currently doing)

Now the tests pass and I think they are reasonable. Tell me what you think ;-)

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication