{"id":6504,"date":"2020-11-19T03:04:04","date_gmt":"2020-11-19T08:04:04","guid":{"rendered":"http:\/\/springframework.guru\/?p=6504"},"modified":"2021-01-14T17:09:07","modified_gmt":"2021-01-14T22:09:07","slug":"testing-spring-boot-restful-services","status":"publish","type":"post","link":"https:\/\/springframework.guru\/testing-spring-boot-restful-services\/","title":{"rendered":"Testing Spring Boot RESTful Services"},"content":{"rendered":"

A Spring Boot RESTful service is typically divided into three layers: \u00a0Repository, Service, and Controller. This layering helps to segregate<\/a> the RESTful application responsibilities and enabling loose coupling between the objects.<\/p>\n

When you develop a layered RESTful application, you will also need to test the different layers.<\/p>\n

In this post, I will discuss testing Spring Boot RESTful Services with Spring MVC Test and JUnit5.<\/p>\n

The Maven POM<\/h2>\n

To start testing Spring Boot RESTful services, you need spring-boot-starter-test<\/code>, which is a starter dependency for Spring Testing.<\/p>\n

This Spring Boot starter depenency also transitively brings in other testing dependencies such as Mockito<\/code><\/a>, JUnit<\/code><\/a>, Hamcrest<\/code><\/a>, AssertJ<\/code><\/a>.<\/p>\n

This is the dependency you need to add in the pom.xml file.<\/p>\n

<dependency>\r\n     <groupId>org.springframework.boot<\/groupId>\r\n     <artifactId>spring-boot-starter-test<\/artifactId>\r\n     <scope>test<\/scope>\r\n     <exclusions>\r\n         <exclusion>\r\n             <groupId>org.junit.vintage<\/groupId>\r\n             <artifactId>junit-vintage-engine<\/artifactId>\r\n         <\/exclusion>\r\n     <\/exclusions>\r\n<\/dependency>\r\n<\/pre>\n
Testing the Repository Layer<\/h2>\n
This is the repository I will be testing.<\/p>\n
@Repository\r\npublic interface ProductRepository extends JpaRepository <Product, Integer> {\r\n\r\n}\r\n<\/pre>\n
Let\u2019s start writing the test class, ProductRepositoryTest<\/code> .<\/p>\n
@ExtendWith(SpringExtension.class)\r\n@DataJpaTest\r\nclass ProductRepositoryTest {<\/pre>\n
The first statement annotates the class with @ExtendWith(SpringExtension.class)<\/code>.\u00a0 This integrates the Spring test context framework into the JUnit 5<\/a> Jupiter programming model.<\/p>\n
Our test will be an integration test as an external database is used. Being an integration test, we need to load the Spring context in our test. We can do that using the @SpringBootTest<\/code> annotation.<\/p>\n
However, loading the entire Spring context is heavy and makes the tests slow.<\/p>\n
Therefore, we will only load the Spring Data JPA slice of the Spring context. The @DataJpaTest<\/code> annotation in the code does exactly that.<\/p>\n
Next, let\u2019s autowire the ProductRepository<\/code> that we will test and write the setup() <\/code> and teardown()<\/code> methods.<\/p>\n
    @Autowired\r\n    private ProductRepository productRepository;\r\n    private Product product;\r\n\r\n    @BeforeEach\r\n    public void setUp() {\r\n\r\n        product = new Product(1,\"Bat\",2500);\r\n    }\r\n\r\n    @AfterEach\r\n    public void tearDown() {\r\n        productRepository.deleteAll();\r\n        product = null;\r\n    }\r\n<\/pre>\n
Test Case for Saving a Product<\/h3>\n
Let\u2019s start writing a test for saving a product.<\/p>\n
The test code is this.<\/p>\n
@Test\r\npublic void givenProductToAddShouldReturnAddedProduct(){\r\n\r\n     productRepository.save(product);\r\n     Product fetchedProduct = productRepository.findById(product.getId()).get();\r\n\r\n     assertEquals(1, fetchedProduct.getId());\r\n}\r\n<\/pre>\n
Test Case to Retrieve the List of Products<\/h3>\n
This test code tests for the retrieval of all products.<\/p>\n
@Test\r\npublic void GivenGetAllProductShouldReturnListOfAllProducts(){\r\n     Product product1 = new Product(1,\"ball\",400);\r\n     Product product2 = new Product(2,\"bat\",500);\r\n     productRepository.save(product1);\r\n     productRepository.save(product2);\r\n\r\n     List<Product> productList = (List<Product>) productRepository.findAll();\r\n     assertEquals(\"bat\", productList.get(1).getName());\r\n\r\n}<\/pre>\n
Test Case to Retrieve Product by Id<\/h3>\n
This test code tests for retrieving a product by ID.<\/p>\n
@Test\r\npublic void givenIdThenShouldReturnProductOfThatId() {\r\n     Product product1 = new Product(1,\"bat\",3000);\r\n     Product product2 = productRepository.save(product1);\r\n\r\n     Optional<Product> optional =\u00a0 productRepository.findById(product2.getId());\r\n     assertEquals(product2.getId(), optional.get().getId());\r\n     assertEquals(product2.getName(), optional.get().getName());\r\n}<\/pre>\n
Test Case to Delete a Product by Id<\/h3>\n
Finally, this test code tests for the deletion of products.<\/p>\n
@Test\r\npublic void givenIdTODeleteThenShouldDeleteTheProduct() {\r\n      Product product = new Product(4,\u00a0 \"pen\",160);\r\n      productRepository.save(product);\r\n      productRepository.deleteById(product.getId());\r\n      Optional optional = productRepository.findById(product.getId());\r\n      assertEquals(Optional.empty(), optional);\r\n}\r\n<\/pre>\n
Let\u2019s run the tests, as you can see from the output provided below, all the test case passes.<\/p>\n
\"test<\/a><\/p>\n
Testing the Service Layer<\/h2>\n
The Service layer class ProductServiceImpl<\/code> is responsible for using the repository for performing CRUD operation.<\/p>\n
This is the code of the ProductServiceImpl<\/code> class.<\/p>\n
ProductServiceImpl.java<\/strong><\/p>\n
@Service\r\npublic class ProductServiceImpl implements ProductService{\r\n\r\n    private ProductRepository productRepository;\r\n\r\n    @Autowired\r\n    public void setProductRepository(ProductRepository productRepository){\r\n          this.productRepository =productRepository;\r\n    }\r\n\r\n    @Override\r\n    public Product addProduct(Product product) throws ProductAlreadyExistsException {\r\n        if(productRepository.existsById(product.getId())){\r\n            throw new ProductAlreadyExistsException();\r\n        }\r\n        return productRepository.save(product);\r\n    }\r\n\r\n    @Override\r\n    public List<Product> getAllProducts() {\r\n\r\n        return (List<Product>) productRepository.findAll();\r\n    }\r\n\r\n    @Override\r\n    public Product getProductByid(int id) {\r\n        return productRepository.findById(id).orElse(null);\r\n    }\r\n\r\n    @Override\r\n    public Product deleteProductById(int id) {\r\n        Product product = null;\r\n        Optional optional = productRepository.findById(id);\r\n        if (optional.isPresent()) {\r\n            product = productRepository.findById(id).get();\r\n            productRepository.deleteById(id);\r\n        }\r\n        return product;\r\n    }\r\n<\/pre>\n
We will write pure unit tests of the service implementation \u2013 ProductServiceImpl<\/code>. The reason is that unit tests are super-fast and therefore cuts down developers’ time.<\/p>\n
Note that in unit testing, when we have external dependencies, we mock the dependencies.\u00a0 So in this example, we will mock the ProductRepository<\/code> class.<\/p>\n
For more information on mocking, refer to my post Mocking in Unit Tests with Mockito<\/a>.<\/p>\n
Let’s start writing the code. The code for the unit test is this.<\/p>\n
@ExtendWith(MockitoExtension.class)\r\nclass ProductServiceTest {\r\n\r\n\r\n    @Mock\r\n    private ProductRepository productRepository;\r\n\r\n    @Autowired\r\n    @InjectMocks\r\n    private ProductServiceImpl productService;\r\n    private Product product1;\r\n    private Product product2;\r\n    List<Product> productList;\r\n\r\n    @BeforeEach\r\n    public void setUp() {\r\n    productList = new ArrayList<>();\r\n    product1 = new Product(1, \"bread\",20);\r\n    product2 = new Product(2, \"jam\",200);\r\n    productList.add(product1);\r\n    productList.add(product2);\r\n    }\r\n\r\n    @AfterEach\r\n    public void tearDown() {\r\n    product1 = product2 = null;\r\n    productList = null;\r\n    }\r\n<\/pre>\n
Line 1 uses annotation. This MockitoExtension<\/code> is a part of the Mockito library that is used to perform mocking. It initializes mocks in test classes.<\/p>\n
Then, Line5 \u2013 Line 6 uses the @Mock<\/code> annotation on ProductRepository<\/code>. At run time, Mockito will create a mock of ProductRepository<\/code>.<\/p>\n
Finally, Line 8-Line10 uses the @Autowired <\/code> annotation to autowire in ProductServiceImpl<\/code> . The @InjectMock<\/code> the annotation will initialize the \u00a0ProductServiceImpl<\/code> \u00a0object with the ProductRepository<\/code> mock.<\/p>\n
Test Case for Saving a Product<\/h3>\n
The test code\u00a0for saving a product is this.<\/p>\n
@Test\r\nvoid givenProductToAddShouldReturnAddedProduct() throws ProductAlreadyExistsException{\r\n\r\n     \/\/stubbing\r\n     when(productRepository.save(any())).thenReturn(product1);\r\n     productService.addProduct(product1);\r\n     verify(productRepository,times(1)).save(any());\r\n\r\n}\r\n<\/pre>\n
Test Code for Retrieval of all Products<\/h3>\n
@Test\r\npublic void GivenGetAllUsersShouldReturnListOfAllUsers(){\r\n     productRepository.save(product1);\r\n    \/\/stubbing mock to return specific data\r\n    when(productRepository.findAll()).thenReturn(productList);\r\n    List<Product> productList1 =productService.getAllProducts();\r\n    assertEquals(productList1,productList);\r\n    verify(productRepository,times(1)).save(product1);\r\n    verify(productRepository,times(1)).findAll();\r\n}\r\n<\/pre>\n
Test Case to Retrieve a Product by Id<\/h3>\n
The test code which tests for retrieving a product by ID is this.<\/p>\n
@Test\r\npublic void givenIdThenShouldReturnProductOfThatId() {\r\n   Mockito.when(productRepository.findById(1)).thenReturn(Optional.ofNullable(product1));\r\n   assertThat(productService.getProductByid(product1.getId())).isEqualTo(product1);\r\n}\r\n<\/pre>\n
Test Case to Delete a Product by Id<\/h3>\n
The test code for deleting a product of the respective id.<\/p>\n
@Test\r\npublic void givenIdTODeleteThenShouldDeleteTheProduct(){\r\n    when(productService.deleteProductById(product1.getId())).thenReturn(product1);\r\n\/\/assertThat(productService.);\r\n    verify(productRepository,times(1)).findAll();\r\n\r\n}\r\n<\/pre>\n
Let\u2019s run the tests.<\/p>\n
As you can see from the output provided below, all the test cases pass.<\/p>\n
\"junit<\/a><\/p>\n
Testing the Controller Layer<\/h2>\n
We will also write a pure unit test for the controller.<\/p>\n
The code of the ProductController.java<\/strong> class that we will test is this.<\/p>\n
@RestController\r\n@RequestMapping(\"api\/v1\")\r\npublic class ProductController {\r\n    private ProductService productService;\r\n\r\n    public ProductController(ProductService productService) {\r\n        this.productService = productService;\r\n    }\r\n\r\n    @PostMapping(\"product\")\r\n    public ResponseEntity<Product> addProduct(@RequestBody Product product) throws ProductAlreadyExistsException {\r\n        Product saveProduct = productService.addProduct(product);\r\n        return new ResponseEntity<>(saveProduct, HttpStatus.CREATED);\r\n    }\r\n\r\n    @GetMapping(\"products\")\r\n    public ResponseEntity<List<Product>> getAllProducts(){\r\n\r\n        return new ResponseEntity<List<Product>>(\r\n                (List <Product>) productService.getAllProducts(),HttpStatus.OK);\r\n    }\r\n\r\n    @GetMapping(\"product\/{id}\")\r\n    public ResponseEntity<Product> getProductById(@PathVariable(\"id\") int id){\r\n        return new ResponseEntity<>(productService.getProductByid(id),HttpStatus.OK);\r\n    }\r\n\r\n\r\n    @DeleteMapping(\"product\/{id}\")\r\n        public ResponseEntity<Product> deleteProduct(@PathVariable(\"id\") int id) {\r\n        ResponseEntity responseEntity;\r\n        Product deletedProduct = productService.deleteProductById(id);\r\n        responseEntity = new ResponseEntity<Product>(deletedProduct, HttpStatus.OK);\r\n\r\n        return responseEntity;\r\n   }\r\n\r\n}\r\n<\/pre>\n
As you can see in the preceding code, the controller has a dependency on the service class, ProductService<\/code>.<\/p>\n
So in our test, we will use Mockito to mock ProductService<\/code> and inject a mock on ProductController<\/code>.<\/p>\n
Now, let’s start writing the test class.<\/p>\n
@ExtendWith(MockitoExtension.class)\r\nclass ProductControllerTest {\r\n\r\n   @Mock\r\n   private ProductService productService;\r\n   private Product product;\r\n   private List<Product> productList;\r\n\r\n   @InjectMocks\r\n   private ProductController productController;\r\n\r\n   @Autowired\r\n   private MockMvc mockMvc;\r\n\r\n   @BeforeEach\r\n   public void setup(){\r\n   product = new Product(1,\"ball\",670);\r\n   mockMvc = MockMvcBuilders.standaloneSetup(productController).build();\r\n   }\r\n\r\n   @AfterEach\r\n   void tearDown() {\r\n   product = null;\r\n}\r\n<\/pre>\n
Line 4-Line5 uses the @Mock<\/code> annotation on ProductService<\/code> . At run time, Mockito will create a mock of ProductService<\/code>.<\/p>\n
Next, Line 12-Line13 uses the @Autowired<\/code> annotation to autowire in MockMvc<\/code>. The @InjectMock<\/code> annotation will initialize the \u00a0ProductController<\/code> object.<\/p>\n
We need to send HTTP requests to the controller from our test class to assert they are responding as expected. For that, Line 18 uses\u00a0 MockMvc<\/code>.<\/p>\n
MockMvc<\/code> provides a powerful way to mock Spring MVC.\u00a0 Through @MockMvc<\/code> you can send MockHttp<\/code> request to a controller and test how the controller responds.<\/p>\n
You can create instance of mockMvc<\/code>\u00a0 through two methods of MockMvcBuilders<\/code>. I have used standaloneSetup<\/code> which registers the controller instances.\u00a0 The other one is the webappContextSetup<\/code> method.<\/p>\n
Test Case to Post a Product<\/h3>\n
Let\u2019s write a test for posting a product.<\/p>\n
@Test\r\npublic void PostMappingOfProduct() throws Exception{\r\n   when(productService.addProduct(any())).thenReturn(product);\r\n   mockMvc.perform(post(\"\/api\/v1\/product\").\r\n           contentType(MediaType.APPLICATION_JSON).\r\n           content(asJsonString(product))).\r\n           andExpect(status().isCreated());\r\n   verify(productService,times(1)).addProduct(any());\r\n}<\/pre>\n
In-Line 4-Line 7, mockMvc<\/code> performs a post-operation of product on the URL \"\/api\/v1\/product\" <\/code>\u00a0 whose content type is\u00a0 APPLICATION_JSON<\/code>. \u00a0The status is isCreated()<\/code>.<\/p>\n
Test Case to Retrieve all Products<\/h3>\n
This test uses mockMvc<\/code> to send a GET request to retrieve all products<\/p>\n
@Test\r\npublic void GetMappingOfAllProduct() throws Exception {\r\n    when(productService.getAllProducts()).thenReturn(productList);\r\n    mockMvc.perform(MockMvcRequestBuilders.get(\"\/api\/v1\/products\").\r\n                   contentType(MediaType.APPLICATION_JSON).\r\n                   content(asJsonString(product))).\r\n                   andDo(MockMvcResultHandlers.print());\r\n    verify(productService).getAllProducts();\r\n    verify(productService,times(1)).getAllProducts();\r\n}\r\n<\/pre>\n
In-Line 4-Line 7, mockMvc<\/code> performs a GET request to retrieve all products from the URL \"\/api\/v1\/products \" <\/code> whose content type is Json<\/code>. The content is JsonString<\/code> of product details.<\/p>\n
This is the output on running the test.<\/p>\n
\"retrieving<\/a><\/h3>\n
Test Case to Retrieve Product by Id<\/h3>\n
This test uses mockMvc<\/code> to send a GET request to retrieve a product with a given id.<\/p>\n
@Test\r\npublic void GetMappingOfProductShouldReturnRespectiveProducct() throws Exception {\r\n    when(productService.getProductByid(product.getId())).thenReturn(product);\r\n    mockMvc.perform(get(\"\/api\/v1\/product\/1\").\r\n           contentType(MediaType.APPLICATION_JSON).\r\n           content(asJsonString(product))).\r\n           andExpect(MockMvcResultMatchers.status().isOk()).\r\n           andDo(MockMvcResultHandlers.print());\r\n}<\/pre>\n
Similarly, in Line 4-Line 8, mockmvc<\/code> performs a GET request to retrieve a product with given product id 1 from the URL \"\/api\/v1\/product\/1 \" <\/code>. Its content type is Json<\/code> and content is JsonString<\/code> of product details.<\/p>\n
The output on running the test is this.<\/p>\n
\"product<\/a><\/p>\n
Test Case to Delete a Product<\/h3>\n
This test uses mockMvc<\/code> to send a DELETE request to delete a product with a given id.<\/p>\n
@Test\r\npublic void DeleteMappingUrlAndIdThenShouldReturnDeletedProduct() throws Exception {\r\n      when(productService.deleteProductById(product.getId())).thenReturn(product);\r\n      mockMvc.perform(delete(\"\/api\/v1\/product\/1\")\r\n      .contentType(MediaType.APPLICATION_JSON)\r\n      .content(asJsonString(product)))\r\n      .andExpect(MockMvcResultMatchers.status().isOk()).\r\n      andDo(MockMvcResultHandlers.print());\r\n}\r\n\r\npublic static String asJsonString(final Object obj){\r\n    try{\r\n        return new ObjectMapper().writeValueAsString(obj);\r\n    }catch (Exception e){\r\n           throw new RuntimeException(e);\r\n      }\r\n}<\/pre>\n
In Line 4-Line 8, mockmvc<\/code> performs a DELETE request to delete a product with id 1 from the URL\u00a0 \"\/api\/v1\/product\/1 \" <\/code> . The\u00a0 content type is Json<\/code>. The content is JsonString<\/code> of product details.<\/p>\n
Now, let’s run the test cases.<\/p>\n
The output shows below that all the test cases passed.<\/p>\n
\"test<\/a><\/p>\n
You can find the source code of this post on Github<\/a>.<\/p>\n
For in-depth knowledge of the Spring Framework check my Udemy Best Seller Course Spring Framework 5: Beginner to Guru<\/a>.<\/p>\n
If you’d like to learn more about testing Spring Boot applications with Mockito and JUnit 5, checkout my course Testing Spring Boot: Beginner to Guru<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"
A Spring Boot RESTful service is typically divided into three layers: \u00a0Repository, Service, and Controller. This layering helps to segregate the RESTful application responsibilities and enabling loose coupling between the objects. When you develop a layered RESTful application, you will also need to test the different layers. In this post, I will discuss testing Spring […]Continue reading<\/a><\/p>\n","protected":false},"author":111,"featured_media":4658,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_lmt_disableupdate":"","_lmt_disable":"","_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false},"version":2}},"categories":[33,21,104,182,330,85],"tags":[314,208,313,333,315,316,331,332],"class_list":["post-6504","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-junit","category-spring","category-spring-boot","category-spring-framework-5","category-spring-test","category-testing","tag-mock","tag-junit-5","tag-mockmvc","tag-spring-test","tag-testing-different-layers-of-spring-boot","tag-testing-repository","tag-testing-rest-controllers","tag-testing-rest-services"],"jetpack_publicize_connections":[],"aioseo_notices":[],"modified_by":"jt","jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/springframework.guru\/wp-content\/uploads\/2017\/07\/Testing-Spring-Boot03cweb.jpg","jetpack_shortlink":"https:\/\/wp.me\/p5BZrZ-1GU","_links":{"self":[{"href":"https:\/\/springframework.guru\/wp-json\/wp\/v2\/posts\/6504"}],"collection":[{"href":"https:\/\/springframework.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/springframework.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/springframework.guru\/wp-json\/wp\/v2\/users\/111"}],"replies":[{"embeddable":true,"href":"https:\/\/springframework.guru\/wp-json\/wp\/v2\/comments?post=6504"}],"version-history":[{"count":11,"href":"https:\/\/springframework.guru\/wp-json\/wp\/v2\/posts\/6504\/revisions"}],"predecessor-version":[{"id":6799,"href":"https:\/\/springframework.guru\/wp-json\/wp\/v2\/posts\/6504\/revisions\/6799"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/springframework.guru\/wp-json\/wp\/v2\/media\/4658"}],"wp:attachment":[{"href":"https:\/\/springframework.guru\/wp-json\/wp\/v2\/media?parent=6504"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/springframework.guru\/wp-json\/wp\/v2\/categories?post=6504"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/springframework.guru\/wp-json\/wp\/v2\/tags?post=6504"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}