Fix swapping out Database in tests

Previously overwrote the object itself for a quick swap of DatabaseInitialization, but that only works over API 24.
So now we will use loadKoinModules instead, which resolves the issue on ani API level

app/src/androidTest/java/org/fnives/test/showcase/endtoend/LoginLogoutEndToEndTest.kt

@@ -12,12 +12,12 @@ import androidx.test.runner.AndroidJUnit4
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import org.fnives.test.showcase.R
 import org.fnives.test.showcase.network.testutil.NetworkTestConfigurationHelper
-import org.fnives.test.showcase.storage.database.DatabaseInitialization
 import org.fnives.test.showcase.testutils.idling.CompositeDisposable
 import org.fnives.test.showcase.testutils.idling.Disposable
 import org.fnives.test.showcase.testutils.idling.IdlingResourceDisposable
 import org.fnives.test.showcase.testutils.idling.OkHttp3IdlingResource
 import org.fnives.test.showcase.testutils.idling.loopMainThreadFor
+import org.fnives.test.showcase.testutils.storage.TestDatabaseInitialization
 import org.fnives.test.showcase.ui.splash.SplashActivity
 import org.hamcrest.Description
 import org.hamcrest.Matcher
@@ -45,7 +45,7 @@ class LoginLogoutEndToEndTest {
     @Before
     fun before() {
         /** Needed to add the dispatcher to the Database */
-        DatabaseInitialization.dispatcher = UnconfinedTestDispatcher()
+        TestDatabaseInitialization.overwriteDatabaseInitialization(UnconfinedTestDispatcher())
 
         /** Needed to register the Okhttp as Idling resource, so Espresso actually waits for the response.*/
         val idlingResources = NetworkTestConfigurationHelper.getOkHttpClients()

app/src/robolectricTest/java/org/fnives/test/showcase/storage/favourite/FavouriteContentLocalStorageImplInstrumentedTest.kt

@@ -12,7 +12,7 @@ import kotlinx.coroutines.test.runTest
 import org.fnives.test.showcase.core.integration.fake.FakeFavouriteContentLocalStorage
 import org.fnives.test.showcase.core.storage.content.FavouriteContentLocalStorage
 import org.fnives.test.showcase.model.content.ContentId
-import org.fnives.test.showcase.storage.database.DatabaseInitialization
+import org.fnives.test.showcase.testutils.storage.TestDatabaseInitialization
 import org.junit.After
 import org.junit.Assert
 import org.junit.Before
@@ -36,7 +36,7 @@ internal class FavouriteContentLocalStorageImplInstrumentedTest(
     @Before
     fun setUp() {
         testDispatcher = StandardTestDispatcher()
-        DatabaseInitialization.dispatcher = testDispatcher
+        TestDatabaseInitialization.overwriteDatabaseInitialization(testDispatcher)
         sut = favouriteContentLocalStorageFactory()
     }
 

app/src/robolectricTest/java/org/fnives/test/showcase/ui/RobolectricAuthActivityInstrumentedTest.kt

@@ -14,13 +14,13 @@ import org.fnives.test.showcase.R
 import org.fnives.test.showcase.network.mockserver.MockServerScenarioSetup
 import org.fnives.test.showcase.network.mockserver.scenario.auth.AuthScenario
 import org.fnives.test.showcase.network.testutil.NetworkTestConfigurationHelper
-import org.fnives.test.showcase.storage.database.DatabaseInitialization
 import org.fnives.test.showcase.testutils.idling.CompositeDisposable
 import org.fnives.test.showcase.testutils.idling.Disposable
 import org.fnives.test.showcase.testutils.idling.IdlingResourceDisposable
 import org.fnives.test.showcase.testutils.idling.MainDispatcherTestRule.Companion.advanceUntilIdleWithIdlingResources
 import org.fnives.test.showcase.testutils.idling.OkHttp3IdlingResource
 import org.fnives.test.showcase.testutils.safeClose
+import org.fnives.test.showcase.testutils.storage.TestDatabaseInitialization
 import org.fnives.test.showcase.ui.auth.AuthActivity
 import org.junit.After
 import org.junit.Before
@@ -45,7 +45,7 @@ class RobolectricAuthActivityInstrumentedTest : KoinTest {
         val dispatcher = StandardTestDispatcher()
         Dispatchers.setMain(dispatcher)
         testDispatcher = dispatcher
-        DatabaseInitialization.dispatcher = dispatcher
+        TestDatabaseInitialization.overwriteDatabaseInitialization(dispatcher)
 
         mockServerScenarioSetup = NetworkTestConfigurationHelper.startWithHTTPSMockWebServer()
 

app/src/sharedTest/java/org/fnives/test/showcase/storage/database/DatabaseInitialization.kt

@@ -1,21 +0,0 @@
-package org.fnives.test.showcase.storage.database
-
-import android.content.Context
-import androidx.room.Room
-import kotlinx.coroutines.CoroutineDispatcher
-import kotlinx.coroutines.asExecutor
-import org.fnives.test.showcase.storage.LocalDatabase
-
-object DatabaseInitialization {
-
-    lateinit var dispatcher: CoroutineDispatcher
-
-    fun create(context: Context): LocalDatabase {
-        val executor = dispatcher.asExecutor()
-        return Room.inMemoryDatabaseBuilder(context, LocalDatabase::class.java)
-            .setTransactionExecutor(executor)
-            .setQueryExecutor(executor)
-            .allowMainThreadQueries()
-            .build()
-    }
-}

app/src/sharedTest/java/org/fnives/test/showcase/testutils/idling/DispatcherTestRule.kt

@@ -3,8 +3,8 @@ package org.fnives.test.showcase.testutils.idling
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.test.StandardTestDispatcher
 import kotlinx.coroutines.test.TestDispatcher
-import org.fnives.test.showcase.storage.database.DatabaseInitialization
 import org.fnives.test.showcase.testutils.runOnUIAwaitOnCurrent
+import org.fnives.test.showcase.testutils.storage.TestDatabaseInitialization
 import org.junit.rules.TestRule
 import org.junit.runner.Description
 import org.junit.runners.model.Statement
@@ -20,7 +20,7 @@ class DispatcherTestRule : TestRule {
             override fun evaluate() {
                 val dispatcher = StandardTestDispatcher()
                 testDispatcher = dispatcher
-                DatabaseInitialization.dispatcher = dispatcher
+                TestDatabaseInitialization.overwriteDatabaseInitialization(dispatcher)
                 base.evaluate()
             }
         }

app/src/sharedTest/java/org/fnives/test/showcase/testutils/idling/MainDispatcherTestRule.kt

@@ -6,8 +6,8 @@ import kotlinx.coroutines.test.StandardTestDispatcher
 import kotlinx.coroutines.test.TestDispatcher
 import kotlinx.coroutines.test.resetMain
 import kotlinx.coroutines.test.setMain
-import org.fnives.test.showcase.storage.database.DatabaseInitialization
 import org.fnives.test.showcase.testutils.runOnUIAwaitOnCurrent
+import org.fnives.test.showcase.testutils.storage.TestDatabaseInitialization
 import org.junit.rules.TestRule
 import org.junit.runner.Description
 import org.junit.runners.model.Statement
@@ -24,7 +24,7 @@ class MainDispatcherTestRule : TestRule {
                 val dispatcher = StandardTestDispatcher()
                 Dispatchers.setMain(dispatcher)
                 testDispatcher = dispatcher
-                DatabaseInitialization.dispatcher = dispatcher
+                TestDatabaseInitialization.overwriteDatabaseInitialization(dispatcher)
                 try {
                     base.evaluate()
                 } finally {

app/src/sharedTest/java/org/fnives/test/showcase/testutils/storage/TestDatabaseInitialization.kt

@@ -0,0 +1,31 @@
+package org.fnives.test.showcase.testutils.storage
+
+import android.content.Context
+import androidx.room.Room
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.asExecutor
+import org.fnives.test.showcase.storage.LocalDatabase
+import org.koin.android.ext.koin.androidContext
+import org.koin.core.context.loadKoinModules
+import org.koin.dsl.module
+
+/**
+ * Reloads the Database Koin module, so it uses the inMemory database with the switched out Executors.
+ */
+object TestDatabaseInitialization {
+
+    fun create(context: Context, dispatcher: CoroutineDispatcher): LocalDatabase {
+        val executor = dispatcher.asExecutor()
+        return Room.inMemoryDatabaseBuilder(context, LocalDatabase::class.java)
+            .setTransactionExecutor(executor)
+            .setQueryExecutor(executor)
+            .allowMainThreadQueries()
+            .build()
+    }
+
+    fun overwriteDatabaseInitialization(dispatcher: CoroutineDispatcher) {
+        loadKoinModules(module {
+            single { create(androidContext(), dispatcher) }
+        })
+    }
+}

app/src/sharedTest/java/org/fnives/test/showcase/ui/login/codekata/rule/dispatcher/PlainMainDispatcherRule.kt

@@ -8,6 +8,7 @@ import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.resetMain
 import kotlinx.coroutines.test.setMain
 import org.fnives.test.showcase.storage.database.DatabaseInitialization
+import org.fnives.test.showcase.testutils.storage.TestDatabaseInitialization
 import org.junit.rules.TestRule
 import org.junit.runner.Description
 import org.junit.runners.model.Statement
@@ -28,7 +29,7 @@ class PlainMainDispatcherRule(private val useStandard: Boolean = true) : TestRul
             try {
                 val dispatcher = if (useStandard) StandardTestDispatcher() else UnconfinedTestDispatcher()
                 Dispatchers.setMain(dispatcher)
-                DatabaseInitialization.dispatcher = dispatcher
+                TestDatabaseInitialization.overwriteDatabaseInitialization(dispatcher)
                 _testDispatcher = dispatcher
                 base.evaluate()
             } finally {

app/src/test/java/org/fnives/test/showcase/testutils/TestMainDispatcher.kt

@@ -6,14 +6,13 @@ import kotlinx.coroutines.test.StandardTestDispatcher
 import kotlinx.coroutines.test.TestDispatcher
 import kotlinx.coroutines.test.resetMain
 import kotlinx.coroutines.test.setMain
-import org.fnives.test.showcase.storage.database.DatabaseInitialization
 import org.fnives.test.showcase.testutils.TestMainDispatcher.Companion.testDispatcher
 import org.junit.jupiter.api.extension.AfterEachCallback
 import org.junit.jupiter.api.extension.BeforeEachCallback
 import org.junit.jupiter.api.extension.ExtensionContext
 
 /**
- * Custom Junit5 Extension which replaces the [DatabaseInitialization]'s dispatcher and main dispatcher with a [TestDispatcher]
+ * Custom Junit5 Extension which replaces the main dispatcher with a [TestDispatcher]
  *
  * One can access the test dispatcher via [testDispatcher] static getter.
  */
@@ -23,7 +22,6 @@ class TestMainDispatcher : BeforeEachCallback, AfterEachCallback {
     override fun beforeEach(context: ExtensionContext?) {
         val testDispatcher = StandardTestDispatcher()
         privateTestDispatcher = testDispatcher
-        DatabaseInitialization.dispatcher = testDispatcher
         Dispatchers.setMain(testDispatcher)
     }
 

codekata/robolectric.instructionset.md

@@ -186,7 +186,7 @@ class CodeKataFavouriteContentLocalStorage: KoinTest
 - we add a testDispatcher to Room
 - we switch to runTest(testDispatcher)
 
-Since Room has their own exercutors, that could make our tests flaky, since it might get out of sync. Luckily we can switch out these executors, so we do that to make sure our tests run just as we would like them to.
+Since Room has their own executors, that could make our tests flaky, since it might get out of sync. Luckily we can switch out these executors, so we do that to make sure our tests run just as we would like them to.
 
 ```
 private val sut by inject<FavouriteContentLocalStorage>()
@@ -195,7 +195,7 @@ private lateinit var testDispatcher: TestDispatcher
 @Before
 fun setUp() {
     testDispatcher = StandardTestDispatcher()
-    DatabaseInitialization.dispatcher = testDispatcher
+    TestDatabaseInitialization.overwriteDatabaseInitialization(testDispatcher)
 }
 
 @After
@@ -204,15 +204,16 @@ fun tearDown() {
 }
 
 @Test
-fun atTheStartOurDatabaseIsEmpty()= runTest(testDispatcher) {
+fun atTheStartOurDatabaseIsEmpty() = runTest(testDispatcher) {
     sut.observeFavourites().first()
 }
 ```
 
-The line `DatabaseInitialization.dispatcher = testDispatcher` may look a bit mysterious, but all we do with it is to overwrite our original DatabaseInitialization in tests, and use the given Dispatcher as an executor for Room setup.
+The line `TestDatabaseInitialization.overwriteDatabaseInitialization(testDispatcher)` may look a bit mysterious, but all we do with it is overwrite the koin module to use our an InMemoryDatabase in our tests with the Dispatcher used as executor.
 
-> DatabaseInitialization is overwritten in the Test module, by declaring the same class in the same package with the same methods. This is an easy way to switch out an implementation.
+> Above min API 24
-> This might not look the cleanest, so an alternative way is to switch out the koin-module of how to create the database. For this we could use loadKoinModules. In other dependency injection / service locator frameworks this should also be possible.
+> DatabaseInitialization could be overwritten in Test module, by declaring the same class in the same package with the same methods. This is an easy way to switch out an implementation.
+> That might not look the cleanest, so an the presented way of switch out the koin-module creating the database is preferred. In other dependency injection / service locator frameworks this should also be possible.
 
 ### 1. `atTheStartOurDatabaseIsEmpty`
 
@@ -518,7 +519,7 @@ fun tearDown() {
 ```
 
 > Idling Resources comes from Espresso. The idea is that anytime we want to interact with the UI via Espresso, it will await any Idling Resource beforehand. This is handy, since our Network component, (OkHttp) uses it's own thread pool, and we would like to have a way to await the responses.
-> Disposable is just a syntetic-sugar way to remove the OkHttpIdling resource from Espresso when we no longer need it.
+> Disposable is just a synthetic-sugar way to remove the OkHttpIdling resource from Espresso when we no longer need it.
 > Idling Resources also makes it easy for us, to coordinate coroutines with our network responses, since we can await the IdlingResource and advance the Coroutines afterwards.
 
 ##### Coroutine Test Setup
@@ -531,7 +532,7 @@ fun setup() {
     val dispatcher = StandardTestDispatcher()
     Dispatchers.setMain(dispatcher)
     testDispatcher = dispatcher
-    DatabaseInitialization.dispatcher = dispatcher
+    TestDatabaseInitialization.overwriteDatabaseInitialization(testDispatcher)
 }
 
 @After

codekata/sharedtests.instructionset.md

@@ -129,10 +129,10 @@ So that's because something went wrong in our first test. I am describing these
 
 Now, here is a new difference between Robolectric and AndroidTest. In Robolectric, before every test, the Application class is initialized, however in AndroidTests, the Application class is only initialized once.
 This is great if you want to have End-to-End tests that follow each other, but since now we only want to tests some small subsection of the functionality, we have to restart Koin before every tests if it isn't yet started so our tests don't use the same instances.
-We will check if koin is initalized, if it isn't then we simply initalize it:
+We will check if koin is initialized, if it isn't then we simply initialize it:
 ```kotlin
 ...
-DatabaseInitialization.dispatcher = dispatcher
+TestDatabaseInitialization.overwriteDatabaseInitialization(dispatcher)
 if (GlobalContext.getOrNull() == null) {
     val application = ApplicationProvider.getApplicationContext<TestShowcaseApplication>()
     val baseUrl = BaseUrl(BuildConfig.BASE_URL)
@@ -237,7 +237,7 @@ Let's create a TestRule for that setup next.
 val dispatcher = StandardTestDispatcher()
 Dispatchers.setMain(dispatcher)
 testDispatcher = dispatcher
-DatabaseInitialization.dispatcher = dispatcher
+TestDatabaseInitialization.overwriteDatabaseInitialization(dispatcher)
 
 // after
 Dispatchers.resetMain()
@@ -253,7 +253,7 @@ override fun apply(base: Statement, description: Description): Statement = objec
         try {
             val dispatcher = StandardTestDispatcher()
             Dispatchers.setMain(dispatcher)
-            DatabaseInitialization.dispatcher = dispatcher
+            TestDatabaseInitialization.overwriteDatabaseInitialization(dispatcher)
             _testDispatcher = dispatcher
             base.evaluate()
         } finally {