# Unit Test (Java Spring)

## Pre-Action

* Install J Unit and Mockito dependencies 

E.g: Maven

```markup
	<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.12</version>
			<scope>test</scope>
		</dependency>

		<dependency>
			<groupId>org.mockito</groupId>
			<artifactId>mockito-core</artifactId>
			<version>2.23.0</version>
			<scope>test</scope>
		</dependency>
		
		<dependency>
			<groupId>org.mockito</groupId>
			<artifactId>mockito-junit-jupiter</artifactId>
			<version>2.23.0</version>
			<scope>test</scope>
		</dependency>
```

## Stub vs Mock vs Spy

### Stub vs Mock

* Stub: Initialize -> Exercise -> Verify

```java
private class FooStub implements Foo
{
    public String bar()
    {
        return"baz";
    }
}
public class FooCollectionTest
{
    @Test
    public void test()
    {   
        //Initialize 
        FooStub newFooStub = new FooStub();
        FooCollection sut = newFooCollection();
        sut.add(newFooStub.bar());
        sut.add(newFooStub.bar());
        //Exercise and Verify
        assertEquals("bazbaz",sut.joined());
    }
}
```

* Mock: Initialize -> Set up expectations -> Exercise -> Verify

```java
public class FooCollectionTest
{    
    @Mock
    FooStub newFooStub;
    
    //Initialize
    @InjectMock
    FooCollection sut ;
    
    @Test    
    public void test()
    {   
       
        // Setup expectations
        Mockito.doReturn("baz").when(newFooStub).bar();
        
        sut.add(newFooStub.bar());
        sut.add(newFooStub.bar());
        //Exercise and Verify
        assertEquals("bazbaz",sut.joined());
    }
}
```

### Mock vs Spy

* Spy will actually call the real method of the class , while mock doesn't
* Spy

```java
@Test
public void whenCreateSpy_thenCreate() {
    List spyList = Mockito.spy(new ArrayList());
 
    spyList.add("one");
    Mockito.verify(spyList).add("one");
 
    assertEquals(1, spyList.size());
}
```

* Mock

```java
@Test
public void whenCreateMock_thenCreated() {
    List mockedList = Mockito.mock(ArrayList.class);
 
    mockedList.add("one");
    Mockito.verify(mockedList).add("one");
 
    assertEquals(0, mockedList.size());
}
```

## Mockito Method

### doAnswer (used to mock the void type function)

```java
Mockito.doAnswer(invocation->{
    if(invocation != null && invocation.getArguments().length > 0){
        System.out.println("Test Void");
    }
    return null;
}).when(productService).test(Integer input);
```

### doReturn (used to mock the return value of function)

```java
 Mockito.doReturn(0).when(shopService).test(any(Integer.class));
```

## &#x20;Service Testing Example

### TestServiceImpl

```java
package com.example.demo.service.impl;

import com.example.demo.service.ShopService;
import com.example.demo.service.TestService;

public class TestServiceImpl implements TestService {
    Integer addNumber = 2;
    ShopService shopService;
    @Override
    public Integer gg(){
        return 3;
    }

    @Override
    public void testVoid(){

    }
    @Override
    public Integer test(){
        Integer num = gg();
        Integer num2 = shopService.test(10);
        return 1 + num + num2;
    }

}
```

### ShopServiceImpl

```java
package com.example.demo.service.impl;

import com.example.demo.service.ShopService;

public class ShopServiceImpl implements ShopService {
    @Override
    public Integer test(Integer input){
        return input;
    }
}
```

### testServiceTest

```java
package com.example.demo.service;

import com.example.demo.service.impl.TestServiceImpl;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.junit.MockitoJUnitRunner;


import static org.mockito.ArgumentMatchers.any;

@RunWith(MockitoJUnitRunner.class)
public class testServiceTest {

    @Mock
    private ShopService shopService;

    @InjectMocks
    private TestService testService;

      private TestService testService1;

    //Constructor
    public testServiceTest() {
        testService = new TestServiceImpl();
    }
    @Before
    public void setUp() throws Exception{
        testService1 = Mockito.spy(testService);
    }

    @Test
    public void testTest() throws Exception{
        Mockito.when(testService1.gg()).thenReturn(1);
        Mockito.doReturn(0).when(shopService).test(any(Integer.class));
        Mockito.doAnswer(invocationOnMock -> {
            if(invocationOnMock != null && invocationOnMock.getArguments().length>0){
                System.out.println("testvoid");
            }
            return null;
        }).when(testService1).testVoid();
        Integer result = testService1.test();
        Assert.assertSame(2,result);
    }

}
```

## Controller Unit Test

### MockMvc

* Create a new MockMvc Object as a entry point, so that we can use it to call the link of API

```java
@RunWith(MockitoJUnitRunner.class)
public class schoolControllerTest
{
    private MockMvc mockMvc;
    
    private SchoolController schoolController;
    
    @Before
    public void setUp() throws NotFoundException{
        this.mockMvc = MockMvcBuilders.standaloneSetup(schoolController).build();
    } 
}
```

* Method&#x20;

```java
@Test  
public void testView() throws Exception {  
 MvcResult result = mockMvc.perform(MockMvcRequestBuilders.get("/user/1"))  
            .andExpect(MockMvcResultMatchers.view().name("user/view"))  
            .andExpect(MockMvcResultMatchers.model().attributeExists("user"))  
            .andDo(MockMvcResultHandlers.print())  
            .andReturn();  
}  
```

* perform: make a request to api end point
* andExpect: verify the result whether the actual is equal to actual or not
* andDo: to make a handling after getting the result, such as print out the response
* andReturn: return back to MvcResult

### MockMvcRequestBuilders

* Used to create a request
* Methods

```java
MockHttpServletRequestBuilder get(String urlTemplate, Object... urlVariables)：根据uri模板和uri变量值得到一个GET请求方式的MockHttpServletRequestBuilder；如get(/user/{id}, 1L)；

MockHttpServletRequestBuilder post(String urlTemplate, Object... urlVariables)：同get类似，但是是POST方法；

MockHttpServletRequestBuilder put(String urlTemplate, Object... urlVariables)：同get类似，但是是PUT方法；

MockHttpServletRequestBuilder delete(String urlTemplate, Object... urlVariables) ：同get类似，但是是DELETE方法；

MockHttpServletRequestBuilder options(String urlTemplate, Object... urlVariables)：同get类似，但是是OPTIONS方法；

MockHttpServletRequestBuilder request(HttpMethod httpMethod, String urlTemplate, Object... urlVariables)： 提供自己的Http请求方法及uri模板和uri变量，如上API都是委托给这个API；

MockMultipartHttpServletRequestBuilder fileUpload(String urlTemplate, Object... urlVariables)：提供文件上传方式的请求，得到MockMultipartHttpServletRequestBuilder；

RequestBuilder asyncDispatch(final MvcResult mvcResult)：创建一个从启动异步处理的请求的MvcResult进行异步分派的RequestBuilder；
```

### MockMvcResultMatchers

* used to match the result of api end point , such as content-type, https status, return value&#x20;
* Methods

```java
HandlerResultMatchers handler()：请求的Handler验证器，比如验证处理器类型/方法名；此处的Handler其实就是处理请求的控制器；

RequestResultMatchers request()：得到RequestResultMatchers验证器；

ModelResultMatchers model()：得到模型验证器；

ViewResultMatchers view()：得到视图验证器；

FlashAttributeResultMatchers flash()：得到Flash属性验证；

StatusResultMatchers status()：得到响应状态验证器；

HeaderResultMatchers header()：得到响应Header验证器；

CookieResultMatchers cookie()：得到响应Cookie验证器；

ContentResultMatchers content()：得到响应内容验证器；

JsonPathResultMatchers jsonPath(String expression, Object ... args)/ResultMatcher jsonPath  (String expression, Matcher matcher)：得到Json表达式验证器；

XpathResultMatchers xpath(String expression, Object... args)/XpathResultMatchers xpath(String expression, Map<string, string=""> namespaces, Object... args)：得到Xpath表达式验证器；

ResultMatcher forwardedUrl(final String expectedUrl)：验证处理完请求后转发的url（绝对匹配）；

ResultMatcher forwardedUrlPattern(final String urlPattern)：验证处理完请求后转发的url（Ant风格模式匹配，@since spring4）；

ResultMatcher redirectedUrl(final String expectedUrl)：验证处理完请求后重定向的url（绝对匹配）；

ResultMatcher redirectedUrlPattern(final String expectedUrl)：验证处理完请求后重定向的url（Ant风格模式匹配，@since spring4）
```

### MockMvcResultHandlers

* used to print the whole of the response of api end point&#x20;

### Example

```java
@Test
public void getInventoryByProductCodeTest1() throws Exception
{
  mockMvc.perform(MockMvcRequestBuilders.get("/api/getSchool"))
  .andExpect(MockMvcResultMatchers.status().isOk()) // Check the http status
  .andExpect(MockMvcResultMatchers.content().contentTypeCompatibleWith(MediaType.APPLICATION_JSON)) // check the content type
  .andExpect(MockMvcResultMatchers.jsonPath("studentName").value("Tom")); // check the result
}
```

### Reference

<https://www.jianshu.com/p/91045b0415f0>


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