Add instrumented tests for LocalPlaylistManager.createPlaylist

[XiangRongLin]

What is it?

• Codebase improvement (dev facing)

Description of the changes in your PR

• Add instrumented tests for LocalPlaylistManager.createPlaylist

Fixes the following issue(s)

• No automated tests!

Relies on the following changes

• Run Instrumented tests in CI pipeline #5360 So instrumented tests are actually run in the CI pipeline

Due diligence

• I read the contribution guidelines.

Notes

• Besides testing the code, this should also serve as a "how-to" which can be referenced when asking contributors to add tests to classes like this one
• There are 2 weird behaviours which i commented. They should be adressed somewhere seperatly and not here.
• The manager layer and DAO layer is tested together here. Mocking the DAO with Mockito makes the tests very brittle. The example here, also does it like this. See TaskLocalDataSource which should be the equivalent layout to our LocalPlaylistManager https://github.com/android/architecture-samples
• RxJava is unpleasant to test

[Stypox]

@XiangRongLin I like this, thank you. What's the state of the PR?

[XiangRongLin]

#5360 needs to be rebased and merged, which i can do tomorrow

[XiangRongLin]

@Stypox Well i completly forgot that i did something like this.
Now it's rebased and hopefully CI will be successfull

[Stypox]

Thank you, this example is really useful :-)

[XiangRongLin]

This should probably be merged after #6560, to see the test actully pass in CI

[XiangRongLin]

Rebased and tests are passing
@Stypox you need to approve because you requested changes

[Stypox]

Thank you ;-)

[litetex]

@Stypox
@XiangRongLin

I think there is something wrong with the format of the kotlin files.
Whenever I build the dev branch these changes happen:

git diff

$ git diff
diff --git a/app/src/androidTest/java/org/schabi/newpipe/local/playlist/LocalPlaylistManagerTest.kt b/app/src/androidTest/java/org/schabi/newpipe/local/playlist/LocalPlaylistManagerTest.kt
index 9883105f3..211312bc0 100644
--- a/app/src/androidTest/java/org/schabi/newpipe/local/playlist/LocalPlaylistManagerTest.kt
+++ b/app/src/androidTest/java/org/schabi/newpipe/local/playlist/LocalPlaylistManagerTest.kt
@@ -27,11 +27,11 @@ class LocalPlaylistManagerTest {
     @Before
     fun setup() {
         database = Room.inMemoryDatabaseBuilder(
-                ApplicationProvider.getApplicationContext(),
-                AppDatabase::class.java
+            ApplicationProvider.getApplicationContext(),
+            AppDatabase::class.java
         )
-                .allowMainThreadQueries()
-                .build()
+            .allowMainThreadQueries()
+            .build()

         manager = LocalPlaylistManager(database)
     }
@@ -44,8 +44,8 @@ class LocalPlaylistManagerTest {
     @Test
     fun createPlaylist() {
         val stream = StreamEntity(
-                serviceId = 1, url = "https://newpipe.net/", title = "title",
-                streamType = StreamType.VIDEO_STREAM, duration = 1, uploader = "uploader"
+            serviceId = 1, url = "https://newpipe.net/", title = "title",
+            streamType = StreamType.VIDEO_STREAM, duration = 1, uploader = "uploader"
         )

         val result = manager.createPlaylist("name", listOf(stream))
@@ -68,13 +68,13 @@ class LocalPlaylistManagerTest {
     @Test()
     fun createPlaylist_nonExistentStreamsAreUpserted() {
         val stream = StreamEntity(
-                serviceId = 1, url = "https://newpipe.net/", title = "title",
-                streamType = StreamType.VIDEO_STREAM, duration = 1, uploader = "uploader"
+            serviceId = 1, url = "https://newpipe.net/", title = "title",
+            streamType = StreamType.VIDEO_STREAM, duration = 1, uploader = "uploader"
         )
         database.streamDAO().insert(stream)
         val upserted = StreamEntity(
-                serviceId = 1, url = "https://newpipe.net/2", title = "title2",
-                streamType = StreamType.VIDEO_STREAM, duration = 1, uploader = "uploader"
+            serviceId = 1, url = "https://newpipe.net/2", title = "title2",
+            streamType = StreamType.VIDEO_STREAM, duration = 1, uploader = "uploader"
         )

         val result = manager.createPlaylist("name", listOf(stream, upserted))
diff --git a/app/src/androidTest/java/org/schabi/newpipe/testUtil/TrampolineSchedulerRule.kt b/app/src/androidTest/java/org/schabi/newpipe/testUtil/TrampolineSchedulerRule.kt
index 8a12d2439..75f5c6195 100644
--- a/app/src/androidTest/java/org/schabi/newpipe/testUtil/TrampolineSchedulerRule.kt
+++ b/app/src/androidTest/java/org/schabi/newpipe/testUtil/TrampolineSchedulerRule.kt
@@ -18,20 +18,20 @@ class TrampolineSchedulerRule : TestRule {
     private val scheduler = Schedulers.trampoline()

     override fun apply(base: Statement, description: Description): Statement =
-            object : Statement() {
-                override fun evaluate() {
-                    try {
-                        RxJavaPlugins.setComputationSchedulerHandler { scheduler }
-                        RxJavaPlugins.setIoSchedulerHandler { scheduler }
-                        RxJavaPlugins.setNewThreadSchedulerHandler { scheduler }
-                        RxJavaPlugins.setSingleSchedulerHandler { scheduler }
-                        RxAndroidPlugins.setInitMainThreadSchedulerHandler { scheduler }
+        object : Statement() {
+            override fun evaluate() {
+                try {
+                    RxJavaPlugins.setComputationSchedulerHandler { scheduler }
+                    RxJavaPlugins.setIoSchedulerHandler { scheduler }
+                    RxJavaPlugins.setNewThreadSchedulerHandler { scheduler }
+                    RxJavaPlugins.setSingleSchedulerHandler { scheduler }
+                    RxAndroidPlugins.setInitMainThreadSchedulerHandler { scheduler }

-                        base.evaluate()
-                    } finally {
-                        RxJavaPlugins.reset()
-                        RxAndroidPlugins.reset()
-                    }
+                    base.evaluate()
+                } finally {
+                    RxJavaPlugins.reset()
+                    RxAndroidPlugins.reset()
                 }
             }
+        }
 }

Shouldn't the last checks have failed?

[XiangRongLin]

@litetex There is a good chance that i commented out the lines which format the kotlin files while developing. Checkstyle annoys me everytime I'm testing out stuff, which was the case here. And since checkstyle is on the same line as klint both get deactivated.

If that is the case, then can you open a PR with the formatter applied?

[litetex]

Checkstyle annoys me everytime I'm testing out stuff, which was the case here.

Do you mean that kind of thing where the build fails because it's no checkstyle conform?
If yes, we maybe should only warn on local builds and throw an error in CI builds. Is there a known issue for this?
Otherwise I think we should open one ;)

Maybe we should also check the kotlin formatting/linting in the CI?

If that is the case, then can you open a PR with the formatter applied?

→ see #6706

[Stypox]

If yes, we maybe should only warn on local builds and throw an error in CI builds. Is there a known issue for this?

No, this is not a good idea, otherwise newbies wouldn't notice that their app conflicts with checkstyle rules.
I'd rather just check if a local file (say suppress-checkstyle.txt) is present in the ignored .idea folder instead.