Fix #5399: Fix tests in LoggingIdentifierControllerTest (#5409)

## Explanation

Fixes #5399

This PR addresses the problems outlined in #5399 by:
- Ensuring that
``testGetInstallationId_secondAppOpen_providerReturnsSameInstallationIdValue``
and
``testFetchInstallationId_secondAppOpen_returnsSameInstallationIdValue``
are correctly run in a _new_ ``TestApplication`` (as inspired by
``SplashActivityTest``).
- Adding a new test to verify that session ID correctly regenerates in a
new app instance (``testGetSessionId_secondAppOpen_returnsNewRandomId``)
which also has the added benefit of providing confidence that the
earlier tests are correctly verifying that the installation ID _isn't_
changing, as expected, on a new app instance.
- Improved the tests around cache corruption (via emptying) and deletion
to ensure they correctly demonstrate the failure fallbacks (empty/null
for corruption and reinitialization for deletion in the same way as a
new app install).

## Essential Checklist
- [x] The PR title and explanation each start with "Fix #bugnum: " (If
this PR fixes part of an issue, prefix the title with "Fix part of
#bugnum: ...".)
- [x] Any changes to
[scripts/assets](https://github.com/oppia/oppia-android/tree/develop/scripts/assets)
files have their rationale included in the PR explanation.
- [x] The PR follows the [style
guide](https://github.com/oppia/oppia-android/wiki/Coding-style-guide).
- [x] The PR does not contain any unnecessary code changes from Android
Studio
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#undo-unnecessary-changes)).
- [x] The PR is made from a branch that's **not** called "develop" and
is up-to-date with "develop".
- [x] The PR is **assigned** to the appropriate reviewers
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#clarification-regarding-assignees-and-reviewers-section)).

## For UI-specific PRs only
N/A -- This is fixing a specific test and has no impact on UI behaviors.

---------

Co-authored-by: Adhiambo Peres <[email protected]>

domain/src/test/java/org/oppia/android/domain/oppialogger/LoggingIdentifierControllerTest.kt

@@ -1,9 +1,11 @@
 package org.oppia.android.domain.oppialogger
 
 import android.app.Application
+import android.app.Instrumentation
 import android.content.Context
 import androidx.test.core.app.ApplicationProvider
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
 import com.google.common.truth.Truth.assertThat
 import com.google.protobuf.MessageLite
 import dagger.BindsInstance
@@ -73,6 +75,7 @@ class LoggingIdentifierControllerTest {
 
   @Before
   fun setUp() {
+    TestLoggingIdentifierModule.applicationIdSeed = INITIAL_APPLICATION_ID
     setUpTestApplicationComponent()
   }
 
@@ -99,7 +102,8 @@ class LoggingIdentifierControllerTest {
   @Test
   fun testGetInstallationId_secondAppOpen_providerReturnsSameInstallationIdValue() {
     monitorFactory.ensureDataProviderExecutes(loggingIdentifierController.getInstallationId())
-    setUpTestApplicationComponent() // Simulate an app re-open.
+    TestLoggingIdentifierModule.applicationIdSeed = SECOND_APP_OPEN_APPLICATION_ID
+    setUpNewTestApplicationComponent() // Simulate an app re-open with a new app ID.
 
     val installationId =
       monitorFactory.waitForNextSuccessfulResult(loggingIdentifierController.getInstallationId())
@@ -110,15 +114,35 @@ class LoggingIdentifierControllerTest {
 
   @Test
   fun testGetInstallationId_secondAppOpen_emptiedDatabase_providerReturnsEmptyString() {
+    // Simulate initing the installation ID, then emptying/corrupting it, then reopening the app.
+    monitorFactory.ensureDataProviderExecutes(loggingIdentifierController.getInstallationId())
     writeFileCache("device_context_database", DeviceContextDatabase.getDefaultInstance())
+    TestLoggingIdentifierModule.applicationIdSeed = SECOND_APP_OPEN_APPLICATION_ID
+    setUpNewTestApplicationComponent() // Simulate an app re-open with a new app ID.
 
     val installationId =
       monitorFactory.waitForNextSuccessfulResult(loggingIdentifierController.getInstallationId())
 
-    // The installation ID is empty since the database was overwritten.
+    // If the file was emptied, no installation ID can be loaded (this is a critical failure case).
     assertThat(installationId).isEmpty()
   }
 
+  @Test
+  fun testGetInstallationId_secondAppOpen_deletedDatabase_providerReturnsNewInstallationIdValue() {
+    // Simulate initing the installation ID, then deleting it, then reopening the app.
+    monitorFactory.ensureDataProviderExecutes(loggingIdentifierController.getInstallationId())
+    deleteCacheFile("device_context_database")
+    TestLoggingIdentifierModule.applicationIdSeed = SECOND_APP_OPEN_APPLICATION_ID
+    setUpNewTestApplicationComponent() // Simulate an app re-open with a new app ID.
+
+    val installationId =
+      monitorFactory.waitForNextSuccessfulResult(loggingIdentifierController.getInstallationId())
+
+    // It should seem like a reinstallation since the app's data has been cleared after restarting.
+    assertThat(installationId).isEqualTo("a52e69fcfedc")
+    assertThat(installationId.length).isEqualTo(12)
+  }
+
   @Test
   fun testFetchInstallationId_initialAppState_returnsNewInstallationIdValue() {
     val installationId = fetchSuccessfulAsyncValue(loggingIdentifierController::fetchInstallationId)
@@ -130,7 +154,8 @@ class LoggingIdentifierControllerTest {
   @Test
   fun testFetchInstallationId_secondAppOpen_returnsSameInstallationIdValue() {
     monitorFactory.ensureDataProviderExecutes(loggingIdentifierController.getInstallationId())
-    setUpTestApplicationComponent() // Simulate an app re-open.
+    TestLoggingIdentifierModule.applicationIdSeed = SECOND_APP_OPEN_APPLICATION_ID
+    setUpNewTestApplicationComponent() // Simulate an app re-open with a new app ID.
 
     val installationId = fetchSuccessfulAsyncValue(loggingIdentifierController::fetchInstallationId)
 
@@ -140,14 +165,34 @@ class LoggingIdentifierControllerTest {
 
   @Test
   fun testFetchInstallationId_secondAppOpen_emptiedDatabase_returnsNull() {
+    // Simulate initing the installation ID, then emptying/corrupting it, then reopening the app.
+    monitorFactory.ensureDataProviderExecutes(loggingIdentifierController.getInstallationId())
     writeFileCache("device_context_database", DeviceContextDatabase.getDefaultInstance())
+    TestLoggingIdentifierModule.applicationIdSeed = SECOND_APP_OPEN_APPLICATION_ID
+    setUpNewTestApplicationComponent() // Simulate an app re-open with a new app ID.
 
     val installationId = fetchSuccessfulAsyncValue(loggingIdentifierController::fetchInstallationId)
 
-    // The installation ID is null since the database was overwritten.
+    // If the file was emptied, no installation ID can be loaded (this is a critical failure case).
     assertThat(installationId).isNull()
   }
 
+  @Test
+  fun testFetchInstallationId_secondAppOpen_deletedDatabase_returnsNewInstallationIdValue() {
+    // Simulate initing the installation ID, then deleting it, then reopening the app.
+    monitorFactory.ensureDataProviderExecutes(loggingIdentifierController.getInstallationId())
+    deleteCacheFile("device_context_database")
+    TestLoggingIdentifierModule.applicationIdSeed = SECOND_APP_OPEN_APPLICATION_ID
+    setUpNewTestApplicationComponent() // Simulate an app re-open with a new app ID.
+    monitorFactory.ensureDataProviderExecutes(loggingIdentifierController.getInstallationId())
+
+    val installationId = fetchSuccessfulAsyncValue(loggingIdentifierController::fetchInstallationId)
+
+    // The installation ID is null since the database was overwritten.
+    assertThat(installationId).isEqualTo("a52e69fcfedc")
+    assertThat(installationId?.length).isEqualTo(12)
+  }
+
   @Test
   fun testGetSessionId_initialState_returnsRandomId() {
     val sessionIdProvider = loggingIdentifierController.getSessionId()
@@ -167,6 +212,19 @@ class LoggingIdentifierControllerTest {
     assertThat(sessionId).isEqualTo("4d0a66f3-82b6-3aa9-8f61-140bdd5f49d3")
   }
 
+  @Test
+  fun testGetSessionId_secondAppOpen_returnsNewRandomId() {
+    monitorFactory.ensureDataProviderExecutes(loggingIdentifierController.getSessionId())
+    TestLoggingIdentifierModule.applicationIdSeed = SECOND_APP_OPEN_APPLICATION_ID
+    setUpNewTestApplicationComponent() // Simulate an app re-open with a new app ID.
+
+    val sessionIdProvider = loggingIdentifierController.getSessionId()
+
+    // The second call should return the same ID (since the ID doesn't automatically change).
+    val sessionId = monitorFactory.waitForNextSuccessfulResult(sessionIdProvider)
+    assertThat(sessionId).isEqualTo("18c2816d-f7ad-312f-b696-d3fdd51f2e92")
+  }
+
   @Test
   fun testGetSessionIdFlow_initialState_returnsFlowWithRandomId() {
     val sessionIdFlow = loggingIdentifierController.getSessionIdFlow()
@@ -255,6 +313,10 @@ class LoggingIdentifierControllerTest {
     getCacheFile(cacheName).writeBytes(value.toByteArray())
   }
 
+  private fun deleteCacheFile(cacheName: String) {
+    check(getCacheFile(cacheName).delete()) { "Failed to delete: $cacheName." }
+  }
+
   private fun getCacheFile(cacheName: String) = File(context.filesDir, "$cacheName.cache")
 
   private fun File.writeBytes(data: ByteArray) {
@@ -292,6 +354,17 @@ class LoggingIdentifierControllerTest {
     ApplicationProvider.getApplicationContext<TestApplication>().inject(this)
   }
 
+  private fun setUpNewTestApplicationComponent() {
+    createNewTestApplication().inject(this)
+  }
+
+  private fun createNewTestApplication(): TestApplication {
+    return Instrumentation.newApplication(
+      TestApplication::class.java,
+      InstrumentationRegistry.getInstrumentation().targetContext
+    ) as TestApplication
+  }
+
   // TODO(#89): Move this to a common test application component.
   @Module
   class TestModule {
@@ -327,12 +400,12 @@ class LoggingIdentifierControllerTest {
   @Module
   class TestLoggingIdentifierModule {
     companion object {
-      internal const val applicationIdSeed = 1L
+      internal var applicationIdSeed: Long? = null
     }
 
     @Provides
     @ApplicationIdSeed
-    fun provideApplicationIdSeed(): Long = applicationIdSeed
+    fun provideApplicationIdSeed(): Long = applicationIdSeed!! // Fail if not initialized.
   }
 
   @Module
@@ -398,4 +471,9 @@ class LoggingIdentifierControllerTest {
 
     override fun getDataProvidersInjector(): DataProvidersInjector = component
   }
+
+  companion object {
+    private const val INITIAL_APPLICATION_ID = 1L
+    private const val SECOND_APP_OPEN_APPLICATION_ID = 2L
+  }
 }