Mockito - 行為驗證

Mockito 可以確保模擬方法是否以所需引數被呼叫。這是使用verify()方法完成的。請看下面的程式碼片段。

//test the add functionality
Assert.assertEquals(calcService.add(10.0, 20.0),30.0,0);

//verify call to calcService is made or not with same arguments.
verify(calcService).add(10.0, 20.0);

示例 - 使用相同引數的 verify()

步驟 1 - 建立一個名為 CalculatorService 的介面來提供數學函式

檔案: 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);
}

步驟 2 - 建立一個 JAVA 類來表示 MathApplication

檔案: 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);
      return 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);
   }
}

步驟 3 - 測試 MathApplication 類

讓我們透過注入 calculatorService 的模擬物件來測試 MathApplication 類。模擬物件將由 Mockito 建立。

檔案: MathApplicationTester.java

import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

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);
		
      //test the add functionality
      Assert.assertEquals(calcService.add(10.0, 20.0),30.0,0);
       
      //verify the behavior
      verify(calcService).add(10.0, 20.0);
   }
}

步驟 4 - 執行測試用例

在C:\> Mockito_WORKSPACE中建立一個名為 TestRunner 的 java 類檔案來執行測試用例。

檔案: 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());
   }
}

步驟 5 - 驗證結果

使用javac編譯器編譯類，如下所示：

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

現在執行 Test Runner 來檢視結果

C:\Mockito_WORKSPACE>java TestRunner

驗證輸出。

true

示例 - 使用不同引數的 verify()