Room not creating json schema files automatically

Issue

I have a app which is working fine with SQLite database. I wanted to upgrade to Room and I followed this and this articles to test and upgrade from SQLite to Room.

I have created Entities,DAO and Database classes.

Following is my (build.gradle:app)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    buildToolsVersion '28.0.3'

    defaultConfig {
        applicationId "APP ID"
        minSdkVersion 20
        targetSdkVersion 28
        versionCode 10
        versionName "1.4.5"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        javaCompileOptions {
            annotationProcessorOptions {
                arguments = ["room.schemaLocation": "$projectDir/schemas".toString()]
            }
        }




    }
    sourceSets {
        androidTest.assets.srcDirs += files("$projectDir/schemas".toString())
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    repositories {
        maven {
            url 'http://dl.bintray.com/amulyakhare/maven'
        }
    }

}

dependencies {
    def room_version = "1.1.1"
    implementation fileTree(dir: 'libs', include: ['*.jar'])

    // Core library
    androidTestImplementation 'androidx.test:core:1.0.0'



    androidTestImplementation "androidx.test.ext:junit:1.0.0"
    androidTestImplementation 'androidx.test:rules:1.1.0'

    androidTestImplementation 'android.arch.persistence.room:testing:1.1.1'
    implementation "androidx.room:room-runtime:2.1.0-alpha03"



     implementation "androidx.appcompat:appcompat:1.0.2"
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.cardview:cardview:1.0.0'
    implementation 'com.amulyakhare:com.amulyakhare.textdrawable:1.0.1'
    implementation 'com.googlecode.libphonenumber:libphonenumber:8.8.1'
    implementation 'com.facebook.stetho:stetho:1.5.0'
    implementation 'com.google.android.material:material:1.1.0-alpha01'
    implementation 'com.hbb20:ccp:2.0.3'
    implementation 'androidx.recyclerview:recyclerview:1.0.0'
    implementation 'com.google.firebase:firebase-ads:11.4.2'
    implementation 'com.google.firebase:firebase-crash:11.4.2'


}

Following is Test class for creating Database replica

public class SqliteTestDbOpenHelper extends SQLiteOpenHelper {

    public static final int DATABASE_VERSION = 10;

    public SqliteTestDbOpenHelper(Context context, String databaseName) {
        super(context, databaseName, null, DATABASE_VERSION);
    }

    public void onCreate(SQLiteDatabase db) {
        String CREATE_CONTACTS_TABLE = "CREATE TABLE  " + ContactsDBContract.ContactsTable.TABLE_CONTACTS +
                "(" +
                ContactsDBContract.ContactsTable._ID + " INTEGER PRIMARY KEY," + // Define a primary key
                ContactsDBContract.ContactsTable.CONTACT_ID + " TEXT, " +
                ContactsDBContract.ContactsTable.CONTACT_LOOKUP_KEY + " TEXT, " +
                ContactsDBContract.ContactsTable.CONTACT_MESSAGE+ " TEXT, " +
                ContactsDBContract.ContactsTable.CONTACT_NAME+ " TEXT, " +
                ContactsDBContract.ContactsTable.CONTACT_PHONE_NUMBER + " TEXT, " +
                ContactsDBContract.ContactsTable.CONTACT_DATA_VERSION+ " TEXT, " +
                ContactsDBContract.ContactsTable.CONTACT_STAMP_STATUS+ " TEXT, " +
                ContactsDBContract.ContactsTable.CONTACT_MIMETYPE+ " TEXT, " +
                ContactsDBContract.ContactsTable.IS_BLOCK+ " INTEGER " +

                ")";
       String  CREATE_BLOCK_TABLE = "CREATE TABLE  " + ContactsDBContract.BlockTable.TABLE_BLOCKS +
                "(" +
                ContactsDBContract.BlockTable._ID + " INTEGER PRIMARY KEY," + // Define a primary key
                ContactsDBContract.BlockTable.BLOCK_CONTACT_PHONE_NUMBER + " TEXT, " +
                ContactsDBContract.BlockTable.BLOCK_CONTACT_NAME+ " TEXT " +



                ")";
         String CREATE_SCHEDULE_TABLE="CREATE TABLE  " + ContactsDBContract.ScheduleTable.SCHEDULE_TABLE +
                "(" +
                ContactsDBContract.ScheduleTable._ID + " INTEGER PRIMARY KEY," + // Define a primary key
                ContactsDBContract.ScheduleTable.SCHEDULE_START_TIME + " TEXT, " +
                ContactsDBContract.ScheduleTable.SCHEDULE_END_TIME+ " TEXT " +



                ")";

        try {
            db.execSQL(CREATE_BLOCK_TABLE);
            db.execSQL(CREATE_CONTACTS_TABLE);
            db.execSQL(CREATE_SCHEDULE_TABLE);
        } catch (SQLException e) {
            e.printStackTrace();
            FirebaseCrash.report(e);
        }
    }

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Not required as at version 1
    }

    public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Not required as at version 1
    }
}

Below is my Room Database class

@Database(entities = {ContactsData.class,SchedulesData.class,BlocksData.class}, version = 11,exportSchema = true)
public abstract class DatabaseManager extends RoomDatabase {
    private DatabaseManager database;
    public abstract ContactDao contactsDao();
    public abstract SchedulesDao schedulesDao();
    public abstract BlocksDao blocksDao();

    @VisibleForTesting
    public static Migration MIGRATION_10_11 = new Migration(10,11) {
        @Override
        public void migrate(@NonNull SupportSQLiteDatabase database) {
            // nothing to do because we did not change anything
        }
    };

    public DatabaseManager getInstance(Context context){
        if(database == null){
            database = Room.databaseBuilder(context.getApplicationContext(),DatabaseManager.class,"ContactsDB,db")
                    .addMigrations(MIGRATION_10_11).build();
        }
        return database;
    }
}

And below is my Migration test class

 @RunWith(AndroidJUnit4.class)
    public class MigrationTest {

        private static final String TEST_DB_NAME = "Contactsdb";
        // Helper for creating Room databases and migrations
        @Rule
        public MigrationTestHelper mMigrationTestHelper =
                new MigrationTestHelper(InstrumentationRegistry.getInstrumentation(),
                       DatabaseManager.class.getCanonicalName(),
                        new FrameworkSQLiteOpenHelperFactory());

        // Helper for creating SQLite database in version 1
        private SqliteTestDbOpenHelper mSqliteTestDbHelper;

        @Before
        public void setUp() throws Exception {
            // To test migrations from version 1 of the database, we need to create the database
            // with version 1 using SQLite API
            mSqliteTestDbHelper = new SqliteTestDbOpenHelper(ApplicationProvider.getApplicationContext(),
                    TEST_DB_NAME);
            // We're creating the table for every test, to ensure that the table is in the correct state
            SqliteDatabaseTestHelper.createTable(mSqliteTestDbHelper);
        }

        @After
        public void tearDown() throws Exception {
            // Clear the database after every test
            SqliteDatabaseTestHelper.clearDatabase(mSqliteTestDbHelper);
        }

        @Test
        public void migrationFrom1To2_containsCorrectData() throws IOException {
            // Create the database with the initial version 1 schema and insert a user
        SqliteDatabaseTestHelper.addContact(mSqliteTestDbHelper);
            // Create the database with the initial version 1 schema and insert a user
            //SqliteDatabaseTestHelper.insertContact(1, "zaid", mSqliteTestDbHelper);

            mMigrationTestHelper.runMigrationsAndValidate(TEST_DB_NAME, 11, true,
                    MIGRATION_10_11);
            // Get the latest, migrated, version of the database
            DatabaseManager latestDb = getMigratedRoomDatabase();

            // Check that the correct data is in the database
            List<ContactsData> dbUser = latestDb.contactsDao().getAll();
            assertThat(dbUser.size(),is(1));

        }

        @Test
        public void startInVersion2_containsCorrectData() throws IOException {
            // Create the database with version 2
            SupportSQLiteDatabase db = mMigrationTestHelper.createDatabase(TEST_DB_NAME, 3);
            // db has schema version 2. insert some data
            insertContact(db);
            db.close();

            // open the db with Room
            DatabaseManager usersDatabase = getMigratedRoomDatabase();

            // verify that the data is correct
            // Get the latest, migrated, version of the database
            DatabaseManager latestDb = getMigratedRoomDatabase();

            // Check that the correct data is in the database
            List<ContactsData> dbUser = latestDb.contactsDao().getAll();
            assertThat(dbUser.size(),is(1));

        }

        private DatabaseManager getMigratedRoomDatabase() {
            DatabaseManager database = Room.databaseBuilder(ApplicationProvider.getApplicationContext(),
                    DatabaseManager.class, TEST_DB_NAME)
                    .addMigrations(MIGRATION_10_11)
                    .build();
            // close the database and release any stream resources when the test finishes
            mMigrationTestHelper.closeWhenFinished(database);
            return database;
        }

        private void insertContact(SupportSQLiteDatabase db) {

            ContentValues cv=new ContentValues();
            cv.put(ContactsDBContract.ContactsTable.CONTACT_ID,"212222");
            cv.put(ContactsDBContract.ContactsTable.CONTACT_NAME,"Moti");
            cv.put(ContactsDBContract.ContactsTable.CONTACT_LOOKUP_KEY,"Okay-uuss");
            cv.put(ContactsDBContract.ContactsTable.CONTACT_PHONE_NUMBER,"03215467845");

            db.insert(ContactsDBContract.ContactsTable.TABLE_CONTACTS, SQLiteDatabase.CONFLICT_REPLACE, cv);
        }
    }

But when I run/debug migrationFrom1To2_containsCorrectData() test. Im getting following error

Cannot find the schema file in the assets folder. Make sure to include the exported json schemas in your test assert inputs. See https://developer.android.com/topic/libraries/architecture/room.html#db-migration-testing for details. Missing file: package.dummy.manager.DatabaseManager/11.json

It seems schemas are not being created at compile time as explained in official docs. May be I'm understanding something wrong

Solution

Your initial setup of Android Room is incorrect. You missed it's annotation processor dependency. As from official documentation which you can find here Adding components # Room - for AndroidX you should have two lines:

implementation "androidx.room:room-runtime:$room_version"
annotationProcessor "androidx.room:room-compiler:$room_version" // use kapt for Kotlin

Then rebuild project and look inside $projectDir/schemas folder: your schemas should be inside.

Answered By - Andrei Vinogradov