Mockito - 预期调用

Mockito 对可对特定方法进行的调用次数进行特殊的检查。假设 MathApplication 仅应调用一次 CalculatorService.serviceUsed() 方法，那么它应无法多次调用 CalculatorService.serviceUsed()。

//add the behavior of calc service to add two numbers
when(calcService.add(10.0,20.0)).thenReturn(30.00);

//limit the method call to 1, no less and no more calls are allowed
verify(calcService, times(1)).add(10.0, 20.0);

如下创建 CalculatorService 接口。

文件：CalculatorService.java

public interface CalculatorService {
   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);
}

示例

文件：CalculatorService.java

public interface CalculatorService {
   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);
}

步骤 2 − 创建 JAVA 类来表示 MathApplication

文件：MathApplication.java

public class MathApplication {
   private CalculatorService calcService;

   public void setCalculatorService(CalculatorService calcService){
      this.calcService = calcService;
   }
   
   public double add(double input1, double input2){		      
      return calcService.add(input1, input2);		
   }
   
   public double subtract(double input1, double input2){
      return calcService.subtract(input1, input2);
   }
   
   public double multiply(double input1, double input2){
      return calcService.multiply(input1, input2);
   }
   
   public double divide(double input1, double input2){
      return calcService.divide(input1, input2);
   }
}

步骤 3 − 测试 MathApplication 类

让我们通过注入 calculatorService 的模拟来测试 MathApplication 类。模拟将通过 Mockito 创建。

文件：MathApplicationTester.java

import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.never;

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

// @RunWith attaches a runner with the test class to initialize the test data
@RunWith(MockitoJUnitRunner.class)
public class MathApplicationTester {
	
   //@InjectMocks annotation is used to create and inject the mock object
   @InjectMocks 
   MathApplication mathApplication = new MathApplication();

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

   @Test
   public void testAdd(){
      //add the behavior of calc service to add two numbers
      when(calcService.add(10.0,20.0)).thenReturn(30.00);
		
      //add the behavior of calc service to subtract two numbers
      when(calcService.subtract(20.0,10.0)).thenReturn(10.00);
      
      //test the add functionality
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);
      Assert.assertEquals(mathApplication.add(10.0, 20.0),30.0,0);
      
      //test the subtract functionality
      Assert.assertEquals(mathApplication.subtract(20.0, 10.0),10.0,0.0);
      
      //default call count is 1 
      verify(calcService).subtract(20.0, 10.0);
      
      //check if add function is called three times
      verify(calcService, times(3)).add(10.0, 20.0);
      
      //verify that method was never called on a mock
      verify(calcService, never()).multiply(10.0,20.0);
   }
}

步骤 4 − 执行测试用例

在 **C:\> Mockito_WORKSPACE** 中创建一个名为 TestRunner 的 java 类文件来执行测试用例。

文件：TestRunner.java

import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;

public class TestRunner {
   public static void main(String[] args) {
      Result result = JUnitCore.runClasses(MathApplicationTester.class);
      
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
      System.out.println(result.wasSuccessful());
   }
}  	

步骤 5 − 验证结果

使用 **javac** 编译器编译类，如下所示 −

C:\Mockito_WORKSPACE>javac CalculatorService.java MathApplication.
   java MathApplicationTester.java TestRunner.java

现在运行测试运行程序以查看结果 −

C:\Mockito_WORKSPACE>java TestRunner

验证输出。

true