CODEWITHSUNDEEP
androidunit-testingkotlinjunitandroid-room
Rizqi Alif
Rizqi Alif

Reputation: 13

kotlin - Room database error when unit testing

I am trying to write a unit test for my database, but I am getting the following error. The error says that should not be a null value. Through the Log.i, I can know if variable count is a null value. But I don't know why the variable count was worth null.

I/Junit: createDb
I/Junit: createAndRetriveNotes: count= null  3
I/Junit: closeDb

    ----- begin exception -----
E/TestRunner: java.lang.AssertionError: expected:<3> but was:<null>
        at org.junit.Assert.fail(Assert.java:88)
        at org.junit.Assert.failNotEquals(Assert.java:834)
        at org.junit.Assert.assertEquals(Assert.java:118)
        at org.junit.Assert.assertEquals(Assert.java:144)
        at com.riluq.notesapp.DatabaseTest.createAndRetriveDatabase(DatabaseTest.kt:47)
        at java.lang.reflect.Method.invoke(Native Method)
        at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
        at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
        at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
        at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
        at androidx.test.internal.runner.junit4.statement.RunBefores.evaluate(RunBefores.java:80)
        at androidx.test.internal.runner.junit4.statement.RunAfters.evaluate(RunAfters.java:61)
        at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
        at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
        at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
        at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
        at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
        at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
        at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
        at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
        at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
        at androidx.test.runner.AndroidJUnit4.run(AndroidJUnit4.java:104)
        at org.junit.runners.Suite.runChild(Suite.java:128)
        at org.junit.runners.Suite.runChild(Suite.java:27)
        at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
        at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
        at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
        at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
        at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
        at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
        at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
        at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
        at androidx.test.internal.runner.TestExecutor.execute(TestExecutor.java:56)
        at androidx.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:388)
        at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:2090)
    ----- end exception -----

java.lang.AssertionError: expected:<3> but was:<null>
at org.junit.Assert.fail(Assert.java:88)
at org.junit.Assert.failNotEquals(Assert.java:834)
at org.junit.Assert.assertEquals(Assert.java:118)
at org.junit.Assert.assertEquals(Assert.java:144)
at com.riluq.notesapp.DatabaseTest.createAndRetriveDatabase(DatabaseTest.kt:47)
at java.lang.reflect.Method.invoke(Native Method)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at androidx.test.internal.runner.junit4.statement.RunBefores.evaluate(RunBefores.java:80)
at androidx.test.internal.runner.junit4.statement.RunAfters.evaluate(RunAfters.java:61)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at androidx.test.runner.AndroidJUnit4.run(AndroidJUnit4.java:104)
at org.junit.runners.Suite.runChild(Suite.java:128)
at org.junit.runners.Suite.runChild(Suite.java:27)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
at androidx.test.internal.runner.TestExecutor.execute(TestExecutor.java:56)
at androidx.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:388)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:2090)

I have checked my sql queries in NoteDao. kt, but it looks like the problem is not from there.

DatabaseTest.kt

import android.content.Context
import android.util.Log
import androidx.room.Room
import androidx.test.InstrumentationRegistry
import androidx.test.runner.AndroidJUnit4
import com.riluq.notesapp.database.AppDatabase
import com.riluq.notesapp.database.NoteDao
import com.riluq.notesapp.util.getNotes
import org.junit.After
import org.junit.Before
import org.junit.Test
import org.junit.runner.RunWith

import org.junit.Assert.*

@RunWith(AndroidJUnit4::class)
class DatabaseTest {

    companion object{
        val TAG: String = "Junit"
    }

    private var mDb: AppDatabase? = null
    private var mDao: NoteDao? = null

    @Before
    fun createDb() {
        val context: Context = InstrumentationRegistry.getTargetContext()
        mDb = Room.inMemoryDatabaseBuilder(context,
            AppDatabase::class.java).build()
        Log.i(TAG, "createDb")
    }

    @After
    fun closeDb() {
        mDb?.close()
        Log.i(TAG, "closeDb")
    }

    @Test
    fun createAndRetriveDatabase() {
        mDao?.insertNoteAll(getNotes())
        val count: Int? = mDao?.getCount()
        Log.i(TAG, "createAndRetriveNotes: count= $count  " + getNotes().size )
        assertEquals(getNotes().size, count)
    }

}

AppDatabase.kt

import android.content.Context
import androidx.room.*

@Database(entities = [NoteEntity::class], version = 1, exportSchema = false)
@TypeConverters(DateConverter::class)
abstract class AppDatabase: RoomDatabase() {

    abstract fun noteDao(): NoteDao

    companion object {
        val DATABASE_NAME: String = "AppDatabase.db"
        private var INSTANCE: AppDatabase? = null
        fun getInstance(context: Context): AppDatabase? {
            if (INSTANCE == null) {
                synchronized(AppDatabase::class) {
                    if (INSTANCE == null) {
                        INSTANCE = Room.databaseBuilder(context.applicationContext,
                            AppDatabase::class.java, DATABASE_NAME)
                            .build()
                    }
                }
            }
            return INSTANCE
        }

        fun destroyInstance() {
            INSTANCE = null
        }



    }


}

NoteDao.kt

import androidx.lifecycle.LiveData
import androidx.room.*
import androidx.room.OnConflictStrategy.REPLACE

@Dao
interface NoteDao {

    @Insert(onConflict = REPLACE)
    fun insertNote(noteEntity: NoteEntity)

    @Insert(onConflict = REPLACE)
    fun insertNoteAll(notes: List<NoteEntity>)

    @Delete
    fun deleteNote(noteEntity: NoteEntity)

    @Query("SELECT * FROM notes WHERE id = :id")
    fun getNoteById(id: Int): NoteEntity

    @Query("SELECT * FROM notes ORDER BY date DESC")
    fun getAll(): LiveData<List<NoteEntity>>

    @Query("DELETE FROM notes")
    fun deleteAll(): Int

    @Query("SELECT COUNT(*) FROM notes")
    fun getCount(): Int


}

NoteEntity.kt

import androidx.room.Entity
import androidx.room.PrimaryKey
import java.util.*

@Entity(tableName = "notes")
data class NoteEntity(
    @PrimaryKey(autoGenerate = true)
    var id: Int?,
    var date: Date?,
    var text: String
){
    constructor():this(null, null, "")
}

Why the variable count in DatabaseTest.kt value is null? and how do I solve it?

Upvotes: 0

Views: 1078

Answers (1)

Ferry Tan
Ferry Tan

Reputation: 218

It seems like mDao hasn't been initialized yet. should've put mDao = mDb.getNoteDao() in @Before function

Upvotes: 1

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