Issue#67 Extract MigrationTestHelper into separate module

test-util-shared-android/src/main/AndroidManifest.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="org.fnives.test.showcase.android.testutil">
+
+</manifest>

test-util-shared-android/src/main/java/org/fnives/test/showcase/android/testutil/AndroidMigrationTestRule.kt

@@ -0,0 +1,68 @@
+package org.fnives.test.showcase.android.testutil
+
+import android.app.Instrumentation
+import androidx.room.RoomDatabase
+import androidx.room.migration.AutoMigrationSpec
+import androidx.room.migration.Migration
+import androidx.room.testing.MigrationTestHelper
+import androidx.sqlite.db.SupportSQLiteDatabase
+import androidx.sqlite.db.SupportSQLiteOpenHelper
+import org.junit.runner.Description
+import org.junit.runners.model.Statement
+
+/**
+ * Wrapper around [MigrationTestHelper] so it can be created in SharedTests, in both Robolectric and on Device.
+ */
+class AndroidMigrationTestRule : SharedMigrationTestRule {
+
+    private val migrationTestHelper: MigrationTestHelper
+
+    constructor(
+        instrumentation: Instrumentation,
+        databaseClass: Class<out RoomDatabase>
+    ) {
+        migrationTestHelper = MigrationTestHelper(instrumentation, databaseClass)
+    }
+
+    constructor(
+        instrumentation: Instrumentation,
+        databaseClass: Class<out RoomDatabase>,
+        specs: List<AutoMigrationSpec>
+    ) {
+        migrationTestHelper = MigrationTestHelper(instrumentation, databaseClass, specs)
+    }
+
+    constructor(
+        instrumentation: Instrumentation,
+        databaseClass: Class<out RoomDatabase>,
+        specs: List<AutoMigrationSpec>,
+        openFactory: SupportSQLiteOpenHelper.Factory
+    ) {
+        migrationTestHelper = MigrationTestHelper(instrumentation, databaseClass, specs, openFactory)
+    }
+
+    override fun apply(base: Statement, description: Description): Statement =
+        migrationTestHelper.apply(base, description)
+
+    override fun closeWhenFinished(db: RoomDatabase) =
+        migrationTestHelper.closeWhenFinished(db)
+
+    override fun closeWhenFinished(db: SupportSQLiteDatabase) =
+        migrationTestHelper.closeWhenFinished(db)
+
+    override fun createDatabase(name: String, version: Int): SupportSQLiteDatabase =
+        migrationTestHelper.createDatabase(name, version)
+
+    override fun runMigrationsAndValidate(
+        name: String,
+        version: Int,
+        validateDroppedTables: Boolean,
+        vararg migrations: Migration
+    ): SupportSQLiteDatabase =
+        migrationTestHelper.runMigrationsAndValidate(
+            name,
+            version,
+            validateDroppedTables,
+            *migrations
+        )
+}