使用Mockito框架进行测试活动

Question

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);
}

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);
    }

}

我成功地使用JUnit测试了上面的MainActivity.java，但是我是Mockito框架的新手，当我尝试运行CalculatorOperationSmockTest.java文件时，我得到了下面的错误，我不知道如何解决它

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

Answer 1

这里至少存在3个问题：

>

查看以下答案可以解决“空测试套件”错误消息的问题-确保您有一个指定InstrumentationRunner的运行配置。

调用new MainActivity()不能获得活动的实例。正确的成语是：

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

后来呢：

calcService = activityRule.launchActivity(null);