Testing: mocking

Testing: controller
Testing: web app only
2023-07-26 16:12:04 +02:00 · 2023-07-26 14:39:15 +02:00 · 2023-07-26 14:14:28 +02:00 · 2023-07-26 14:08:15 +02:00 · 2023-07-26 14:01:10 +02:00 · 2023-07-26 11:34:43 +02:00
9 changed files with 533 additions and 0 deletions
--- a/README.md
+++ b/README.md
@ -14,3 +14,345 @@ In VsCode press `cmd+shif+p` and type `Spring Initilizr`. Choose next dependenci
 - Thymeleaf
 - Spring Boot DevTools
 # MVC
 ## Web Controller
 In Spring’s approach to building web sites, HTTP requests are handled by a controller. You can easily identify the controller by the [`@Controller`](http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/stereotype/Controller.html) annotation. In the following example, `GreetingController` handles GET requests for `/greeting` by returning the name of a [`View`](http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/web/servlet/View.html) (in this case, `greeting`). A `View` is responsible for rendering the HTML content. The following listing (from `src/main/java/djmil/hellomvc/GreetingController.java`) shows the controller:
 ```java
 package djmil.hellomvc;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestParam;
@Controller
 public class GreetingController {
 	@GetMapping("/greeting")
 	public String greeting(@RequestParam(name="name", required=false, defaultValue="World") String name, Model model) {
 		// NOTE: Here we can request some data from our RESTful backend as well
 		model.addAttribute("name", name);
 		return "greeting"; // <<-- template
 	}
 }
 ```
 This controller is concise and simple, but there is plenty going on. We break it down step by step.
 The `@GetMapping` annotation ensures that HTTP GET requests to `/greeting` are mapped to the `greeting()` method.
 [`@RequestParam`](http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/web/bind/annotation/RequestParam.html) binds the value of the query string parameter `name` into the `name` parameter of the `greeting()` method. This query string parameter is not `required`. If it is absent in the request, the `defaultValue` of `World` is used. The value of the `name` parameter is added to a [`Model`](http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/ui/Model.html) object, ultimately making it accessible to the view template.
 ## Model, View and a Template
 The implementation of the `greeting()` method body relies on a view technology (in this case, [Thymeleaf](http://www.thymeleaf.org/doc/tutorials/2.1/thymeleafspring.html)) to perform server-side rendering of the HTML. 
 > [!note] Make sure you have Thymeleaf on your classpath. Artifact co-ordinates: `org.springframework.boot:spring-boot-starter-thymeleaf`
 Thymeleaf parses the `greeting.html` template and evaluates the `th:text` expression to render the value of the `${name}` parameter that was set in the controller. The following listing `src/main/resources/templates/greeting.html` shows the template:
 ```html
 <!DOCTYPE HTML>
 <html xmlns:th="http://www.thymeleaf.org">
 <head> 
    <title>Getting Started: Serving Web Content</title> 
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
 </head>
 <body>
    <p th:text="'Hello, ' + ${name} + '!'" />
 </body>
 </html>
 ```
 ## Test the Application
 Now that the web site is running, visit http://localhost:8080/greeting, where you should see “Hello, World!”
 Provide a `name` query string parameter by visiting http://localhost:8080/greeting?name=User). Notice how the message changes from “Hello, World!” to “Hello, User!”:
 This change demonstrates that the [`@RequestParam`](http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/web/bind/annotation/RequestParam.html) arrangement in `GreetingController` is working as expected. The `name` parameter has been given a default value of `World`, but it can be explicitly overridden through the query string.
 # Add a Home Page
 Static resources, including HTML and JavaScript and CSS, can be served from your Spring Boot application by dropping them into the right place in the source code. By default, Spring Boot serves static content from resources in the classpath at `/static` (or `/public`). The `index.html` resource is special because, if it exists, it is used as a "welcome page" for serving web-content. Which means it is served up as the root resource (that is, at `http://localhost:8080/`). For this, you need to create the following file `src/main/resources/static/index.html`:
 ```html
 <!DOCTYPE HTML>
 <html>
 <head> 
    <title>Getting Started: Serving Web Content</title> 
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
 </head>
 <body>
    <p>Get your greeting <a href="/greeting">here</a></p>
 </body>
 </html>
 ```
 When you restart the application, you will see the HTML at http://localhost:8080/.
 ## Spring Boot Devtools
 A common feature of developing web applications is coding a change, restarting your application, and refreshing the browser to view the change. This entire process can eat up a lot of time. To speed up this refresh cycle, Spring Boot offers with a handy module known as [spring-boot-devtools](http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#using-boot-devtools):
 - Enables [hot swapping](https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#using.running-your-application.hot-swapping).
 - Switches template engines to disable caching.
 - Enables LiveReload to automatically refresh the browser.
 - Other reasonable defaults based on development instead of production.
 ## Interactivity
 Let's add minimal interactivity to the page by introducing an input field and a button. On the button press, a simple JavaScript will reload the page (by calling [[README#Web Controller]] 's `Get` endpoint) providing a value from the input filed as an URL parameter.  Update `greeting.htm` with next lines:
 ```html
 ...
 <body>
    <p th:text="'Hello, ' + ${name} + '!'" />
 	<input placeholder="Enter username.."/>
 	<button>Go!</button>
 </body>
 </html>
 <script>
    function getName() {
        const name = document.querySelector('input').value;
        console.log(name);
        window.open('http://localhost:8080/greeting?name='+name)
    }
    const button = document.querySelector('button');
    button.addEventListener("click", getName);
 </script>
 ```
 # Testing the Web Layer
 Let's test our simple app with JUnit. We will concentrate on using Spring Test and Spring Boot features to test the interactions between Spring and your code. 
 ## Sanity check
 The first thing you can do is write a simple sanity check test that will fail if the application context cannot start.
 From `src/test/java/djmil/hellomvc/SmokeTest.java`
 ```java
 package djmil.hellomvc;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
 import static org.assertj.core.api.Assertions.assertThat;
@SpringBootTest
 public class SmokeTest {
    @Autowired
 	private GreetingController controller;
    @Test
    void contextLoads() throws Exception {
        assertThat(controller).isNotNull();
    }
 }
 ```
 The `@SpringBootTest` annotation tells Spring Boot to look for a main configuration class (one with `@SpringBootApplication`, for instance) and use that to start a Spring application context. You can run this test in your IDE or on the command line (by running `./mvnw test` or `./gradlew test`), and it should pass.
 Spring interprets the `@Autowired` annotation, and the controller is injected before the test methods are run. We use [AssertJ](http://joel-costigliola.github.io/assertj/) (which provides `assertThat()` and other methods) to express the test assertions.
 > A nice feature of the Spring Test support is that the application context is cached between tests. That way, if you have multiple methods in a test case or multiple test cases with the same configuration, they incur the cost of starting the application only once. You can control the cache by using the @DirtiesContext annotation.
 It is nice to have a sanity check, but you should also write some tests that assert the behavior of your application.
 ## Testing depth
 You can as SpringBoot to test your app at the different depth. Trading test coverage for speed.
 ### HTTP requests: application
 Here, we are starting our application and listen for a connection (as it would do in production) and then send an HTTP request and assert the response. The following listing (from `src/test/java/djmil/hellomvc/HttpRequestTest.java`) shows how to do so:
 ```java
 package djmil.hellomvc;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
 import org.springframework.boot.test.web.client.TestRestTemplate;
 import org.springframework.beans.factory.annotation.Value;
 import static org.assertj.core.api.Assertions.assertThat;
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
 public class HttpRequestTest {
 	@Value(value="${local.server.port}")
 	private int port;
 	@Autowired
 	private TestRestTemplate restTemplate;
 	@Test
 	public void greetingShouldReturnDefaultMessage() throws Exception {
 		assertThat(this.restTemplate.getForObject("http://localhost:" + port + "/greeting",
 				String.class)).contains("Hello, World");
 	}
 }
 ```
 Note the use of `webEnvironment=RANDOM_PORT` to start the server with a random port (useful to avoid conflicts in test environments) and the injection of the port with `@LocalServerPort`. Also, note that Spring Boot has automatically provided a `TestRestTemplate` for you. All you have to do is add `@Autowired` to it.
 ### Web app only
 Another useful approach is **to not start the server at all** but to test only the layer below that, where Spring handles the incoming HTTP request and hands it off to your controller. That way, almost of the full stack is used, and your code will be called in exactly the same way as if it were processing a real HTTP request but without the cost of starting the server. To do that, use Spring’s `MockMvc` and ask for that to be injected for you by using the `@AutoConfigureMockMvc` annotation on the test case. The following listing (from `src/test/java/djmil/hellomvc/WebApplicationTest.java`) shows how to do so:
 ```java
 package djmil.hellomvc;
 import static org.hamcrest.Matchers.containsString;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
 import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.test.web.servlet.MockMvc;
@SpringBootTest
@AutoConfigureMockMvc
 public class WebApplicationTest {
 	@Autowired
 	private MockMvc mockMvc;
 	@Test
 	public void shouldReturnDefaultMessage() throws Exception {
 		this.mockMvc.perform(get("/greeting"))
 				.andDo(print())
 				.andExpect(status().isOk())
 				.andExpect(content().string(containsString("Hello, World")));
 	}
 }
 ```
 In this test, the full Spring application context is started but without the server.
 ###  Controller: web layer only
 We can narrow the tests to only the web layer by using `@WebMvcTest`, as the following listing (from `src/test/java/djmil/hellomvc/WebLayerTest.java`) shows:
 ```java
@WebMvcTest
 public class WebLayerTest {
 	@Autowired
 	private MockMvc mockMvc;
 	@Test
 	public void shouldReturnDefaultMessage() throws Exception {
 		this.mockMvc.perform(get("/greeting")).andDo(print()).andExpect(status().isOk())
 				.andExpect(content().string(containsString("Hello, World")));
 	}
 }
 ```
 The test assertion is the same as in the previous case. However, in this test, Spring Boot instantiates only the web layer rather than the whole context. In an application with multiple controllers, you can even ask for only one to be instantiated by using, for example, `@WebMvcTest(HomeController.class)`.
 ## Testing with mocks 
 So far, our `GreetingController` is simple and has no dependencies. We could make it more realistic by introducing an extra component, say another service which will harbor some business logic, in our case - calculate length of a URL `name` parameter. 
 `src/main/java/djmil/hellomvc/GreetingService.java`
 ```java
 package djmil.hellomvc;
 import org.springframework.stereotype.Service;
 import org.springframework.ui.Model;
@Service
 public class GreetingService {
    public int nameLength(String name) {
        return name.length();
 	}
 }
 ```
 In SpringBoot [`@Service`](https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/stereotype/Service.html) annotation is usually used to mark business logic classes. Doing so allows SpringBoot IoC to handle dependencies between different classes. Here, we have to update `GreetingsControler` to use `GrretingsSrvice` to handle `/greeting` request:
 ```java
@Controller
 public class GreetingController {
    private final GreetingService greetigService;
 	public GreetingController(GreetingService greetigService) {
 		this.greetigService = greetigService;
 	}
 	@GetMapping("/greeting")
 	public String greeting(@RequestParam(name="name", required=false, defaultValue="World") String name, Model model) {
        model.addAttribute("name", name);
        model.addAttribute("nameLength", greetigService.nameLength(name));
        // NOTE: Here we can request some data from our RESTful backend as well
        return "greeting"; // view tempalte
    }
 }
 ```
 Spring IoC will insert instance of `GreetingService` as a constructor parameter of `GreetingController`, which we store as a private class member for later use.
 Also, to make full use of newly created service, update `src\main\resources\templates\greeting.html`:
 ```html
 <p th:text="'Hello, ' + ${name} + '!'" />
 <p th:text="'Length of a given name is ' + ${nameLength} + ' characters.'" />
 ```
 Run the tests, and notice that only `GreetingControllerTest` has failed.
 ### Mocking
 To fix the test, we have to provide mock implementation of a `GreetingService` class inside `GreetingControllerTest`:
 ```java
 import static org.mockito.Mockito.when;
@WebMvcTest(GreetingController.class)
 public class CreetingControllerTests {
 	@Autowired
 	private MockMvc mockMvc;
 	@MockBean
 	private GreetingService service;
 	@Test
 	public void greetingShouldReturnMessageFromService() throws Exception {
 		when(service.nameLength("World")).thenReturn(7);
 		this.mockMvc.perform(get("/greeting"))
 				.andDo(print())
 				.andExpect(status().isOk())
 				.andExpect(content().string(containsString("Length of a given name is 7 characters.")));
 	}
 }
 ```
 Notice the `@MockBean` annotation, which is essentially used to obtain an interface of a mocked class.  Later, `when` function used to define an actual mock.
--- a/src/main/java/djmil/hellomvc/GreetingController.java
+++ b/src/main/java/djmil/hellomvc/GreetingController.java
@ -0,0 +1,27 @@
 package djmil.hellomvc;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestParam;
@Controller
 public class GreetingController {
    private final GreetingService greetigService;
 	public GreetingController(GreetingService greetigService) {
 		this.greetigService = greetigService;
 	}
 	@GetMapping("/greeting")
 	public String greeting(@RequestParam(name="name", required=false, defaultValue="World") String name, Model model) {
        model.addAttribute("name", name);
        model.addAttribute("nameLength", greetigService.nameLength(name));
        // NOTE: Here we can request some data from our RESTful backend as well
        return "greeting"; // view tempalte
    }
 }
--- a/src/main/java/djmil/hellomvc/GreetingService.java
+++ b/src/main/java/djmil/hellomvc/GreetingService.java
@ -0,0 +1,12 @@
 package djmil.hellomvc;
 import org.springframework.stereotype.Service;
@Service
 public class GreetingService {
    public int nameLength(String name) {
        return name.length();
 	}
 }
--- a/src/main/resources/static/index.html
+++ b/src/main/resources/static/index.html
@ -0,0 +1,10 @@
 <!DOCTYPE HTML>
 <html>
 <head> 
    <title>Getting Started: Serving Web Content</title> 
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
 </head>
 <body>
    <p>Get your greeting <a href="/greeting">here</a></p>
 </body>
 </html>
--- a/src/main/resources/templates/greeting.html
+++ b/src/main/resources/templates/greeting.html
@ -0,0 +1,25 @@
 <!DOCTYPE HTML>
 <html xmlns:th="http://www.thymeleaf.org">
 <head> 
    <title>Getting Started: Serving Web Content</title> 
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
 </head>
 <body>
    <p th:text="'Hello, ' + ${name} + '!'" />
    <p th:text="'Length of a given name is ' + ${nameLength} + ' characters.'" />
    <input placeholder="Enter username.."/>
    <button>Go!</button>
 </body>
 </html>
 <script>
    function getName() {
        const name = document.querySelector('input').value;
        console.log(name);
        window.open('http://localhost:8080/greeting?name='+name)
    }
    const button = document.querySelector('button');
    button.addEventListener("click", getName);
 </script>
--- a/src/test/java/djmil/hellomvc/CreetingControllerTests.java
+++ b/src/test/java/djmil/hellomvc/CreetingControllerTests.java
@ -0,0 +1,41 @@
 package djmil.hellomvc;
 import static org.hamcrest.Matchers.containsString;
 import static org.mockito.Mockito.when;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
 import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
 import org.springframework.boot.test.mock.mockito.MockBean;
 import org.springframework.test.web.servlet.MockMvc;
@WebMvcTest(GreetingController.class)
 public class CreetingControllerTests {
 	@Autowired
 	private MockMvc mockMvc;
 	@MockBean
 	private GreetingService service;
 	// @Test
 	// public void shouldReturnDefaultMessage() throws Exception {
 	// 	this.mockMvc.perform(get("/greeting"))
    //             .andDo(print())
    //             .andExpect(status().isOk())
 	// 			.andExpect(content().string(containsString("Hello, World")));
 	// }
 	@Test
 	public void greetingShouldReturnMessageFromService() throws Exception {
 		when(service.nameLength("World")).thenReturn(7);
 		this.mockMvc.perform(get("/greeting"))
 				.andDo(print())
 				.andExpect(status().isOk())
 				.andExpect(content().string(containsString("Length of a given name is 7 characters.")));
 	}
 }
--- a/src/test/java/djmil/hellomvc/HttpRequestTest.java
+++ b/src/test/java/djmil/hellomvc/HttpRequestTest.java
@ -0,0 +1,27 @@
 package djmil.hellomvc;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
 import org.springframework.boot.test.web.client.TestRestTemplate;
 import org.springframework.beans.factory.annotation.Value;
 import static org.assertj.core.api.Assertions.assertThat;
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
 public class HttpRequestTest {
 	@Value(value="${local.server.port}")
 	private int port;
 	@Autowired
 	private TestRestTemplate restTemplate;
 	@Test
 	public void greetingShouldReturnDefaultMessage() throws Exception {
 		assertThat(this.restTemplate.getForObject("http://localhost:" + port + "/greeting",
 				String.class)).contains("Hello, World");
 	}
 }
--- a/src/test/java/djmil/hellomvc/SmokeTest.java
+++ b/src/test/java/djmil/hellomvc/SmokeTest.java
@ -0,0 +1,19 @@
 package djmil.hellomvc;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
 import static org.assertj.core.api.Assertions.assertThat;
@SpringBootTest
 public class SmokeTest {
    @Autowired
 	private GreetingController controller;
    @Test
    void contextLoads() throws Exception {
        assertThat(controller).isNotNull();
    }
 }
--- a/src/test/java/djmil/hellomvc/WebApplicationTest.java
+++ b/src/test/java/djmil/hellomvc/WebApplicationTest.java
@ -0,0 +1,30 @@
 package djmil.hellomvc;
 import static org.hamcrest.Matchers.containsString;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
 import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.test.web.servlet.MockMvc;
@SpringBootTest
@AutoConfigureMockMvc
 public class WebApplicationTest {
 	@Autowired
 	private MockMvc mockMvc;
 	@Test
 	public void shouldReturnDefaultMessage() throws Exception {
 		this.mockMvc.perform(get("/greeting"))
                .andDo(print())
                .andExpect(status().isOk())
 				.andExpect(content().string(containsString("Hello, World")));
 	}
 }
Author	SHA1	Message	Date
djmil	0ddd30a245	Testing: mocking	2023-07-26 16:12:04 +02:00
djmil	45d0361548	Testing: controller	2023-07-26 14:39:15 +02:00
djmil	8e7f231d1f	Testing: web app only	2023-07-26 14:14:28 +02:00
djmil	83e778d739	Testing: Http requests	2023-07-26 14:08:15 +02:00
djmil	e77f67b0b7	Tesing: Sanity check	2023-07-26 14:01:10 +02:00
djmil	141ed6aa7f	Home page	2023-07-26 11:34:43 +02:00
djmil	959364fa12	Interactivity	2023-07-26 10:55:39 +02:00
djmil	4ffe7b8673	Model, View, Controller and a Template	2023-07-26 10:42:54 +02:00