CODEWITHSUNDEEP
javaandroidjunitmockito
DaveTheAl
DaveTheAl

Reputation: 2155

Android JUnit test with Context.getApplicationContext()

I am currently working on an android Room Persistency database project. I have successfully implemented all functions, and am now trying to write unittests for these function. These unittests rely on calling the following function (singleton constructor; I have marked the two important lines with comments):

@Database(entities = {RippleModel.class}, version = 1)
public abstract class AppDatabase extends RoomDatabase {

    public abstract RippleModelDao rippleModelDao();

    private static AppDatabase INSTANCE; //Used for the singleton

    public static AppDatabase getDatabase(Context context) { //THIS LINE
        if (INSTANCE == null) {
            INSTANCE = Room.databaseBuilder(
                            context.getApplicationContext(),
                            AppDatabase.class, "ripple_db"
                        ).build(); //STACKTRACE SHOWS HERE
        }
        return INSTANCE;
    }
}

My current unittest looks as follows:

@RunWith(MockitoJUnitRunner.class)
public class DatabaseUnitTest extends InstrumentationTestCase {

    @Mock
    Context mMockContext = new MockContext();


    @Test
    public void testImportDatabase() throws Exception {
        System.out.println("Importing database..");
        System.out.println(mMockContext);
        System.out.println(mMockContext == null);
        AppDatabase appDatabase = AppDatabase.getDatabase(mMockContext);
    }

}

However, when running this unittest with Mockito, I am getting the following error:

java.lang.IllegalArgumentException: Cannot provide null context for the database.

at android.arch.persistence.room.RoomDatabase$Builder.build(RoomDatabase.java:441)
at io.turtlesquad.ripplebt.data.AppDatabase.getDatabase(AppDatabase.java:20)
at io.turtlesquad.ripplebt.DatabaseUnitTest.testImportDatabase(DatabaseUnitTest.java:43)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
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 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$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37)
at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMainV2.main(AppMainV2.java:131)

I already checked if the Mockito context is not null, using "== null", and this is not the case (the created context is not null).

I am trying to emulate the context with Mockito, but am not sure what I am doing wrong here. Shouldn't Mockito emulate the context? Is there anything I miss?

Upvotes: 1

Views: 1739

Answers (1)

Kavita Patil
Kavita Patil

Reputation: 1864

I have solved the same issue by replacing context.getApplicationContext() with context from parameters of getDatabase(.....) method of AppDatabase class

Replace your AppDaatabase java file with the following code:

@Database(entities = {RippleModel.class}, version = 1)
public abstract class AppDatabase extends RoomDatabase {

public abstract RippleModelDao rippleModelDao();

private static AppDatabase INSTANCE; //Used for the singleton

public static AppDatabase getDatabase(Context context) { //THIS LINE
    if (INSTANCE == null) {
        INSTANCE = Room.databaseBuilder(
                        context,
                        AppDatabase.class, "ripple_db"
                    ).build(); //STACKTRACE SHOWS HERE
    }
    return INSTANCE;
}

}

Upvotes: 6

Related Questions