CODEWITHSUNDEEP
mockingmockitojunit4
Minion Dave
Minion Dave

Reputation: 143

Testing Activity Using Mockito Framework

Below is the Simple Calculator Application and I want to test it using Junit4 and mockito Framework i test that application on Junit4 and it works properly but I am facing problem on mockito implementation

CalculatorOperationsInterfaces.java

public interface CalculatorOperationsInterfaces {
    public double add(double input1, double input2);
    public double subtract(double input1, double input2);
    public double multiply(double input1, double input2);
    public double divide(double input1, double input2);
}

MainActivity.java

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity implements CalculatorOperationsInterfaces {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public double add(double input1, double input2) {
        return (input1 + input2);
    }

    @Override
    public double subtract(double input1, double input2) {
        return (input1 - input2);
    }

    @Override
    public double multiply(double input1, double input2) {
        return (input1 * input2);
    }

    @Override
    public double divide(double input1, double input2) {
        if(input2==0)
            return -1;
        else
            return (input1 / input2);
    }
}

CalculatorOperationsMockTest.java

import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.runners.MockitoJUnitRunner;

import static org.mockito.Mockito.when;

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(MockitoJUnitRunner.class)
public class CalculatorOperationsMockTest {

    //@Mock annotation is used to create the mock object to be injected
    @Mock
    CalculatorOperationsInterfaces calcService;

    @Before
    public void setUp() {
        calcService = new MainActivity();
    }

    @After
    public void tearDown() {
        calcService = null;
    }


    @Test
    public void add(){
        //add the behavior of calc service to add two numbers
        when(calcService.add(10.0,20.0)).thenReturn(30.00);
        //test the add functionality
        Assert.assertEquals(calcService.add(10.0, 20.0),30.0,0);
    }

}

I successfully test the Above MainActivity.java using Junit but I am new to Mockito framework when i try to run the CalculatorOperationsMockTest.java File i am getting the below error and i do not know how to solve it

Class not found: "myappmania.local_jvm_unit_test.CalculatorOperationsMockTest"Empty test suite.

Upvotes: 3

Views: 8421

Answers (1)

David Rawson
David Rawson

Reputation: 21437

There are at least 3 problems here:

  1. The problem with "Empty Test Suite" error message can be solved from looking at this answer - make sure you have a Run Configuration that specifies the InstrumentationRunner.

  2. You can't get an instance of the Activity by calling new MainActivity(). The correct idiom is:

    @Rule
public ActivityTestRule<MainActivity> activityRule = new ActivityTestRule<>(MainActivity.class, true, false);

    and then:

    calcService = activityRule.launchActivity(null);

  3. You are not accomplishing anything by mocking CalculatorService. When testing, you use mocks to test the behaviour of a program called the 'system under test'. Here, your system under test is your implementation of CalculatorService i.e., the Activity. You don't have any dependencies to inject, as far as I can see. I hope this tutorial on mocking can clarify these concepts for you.

Please also check out the instructions in the official tutorial for instrumented unit tests in Android.

Upvotes: 3

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