[JAVA] Write RestController tests quickly with Spring Boot + Spock

Test content

Validate the JSON-formatted response body returned by RestController.

environment

Spring Boot：2.1.1 Spock：1.2 Groovy：2.5 OS：Windows10

Preparation

Add the required libraries for Spring Boot + Spock testing. By writing the dependency on spock-core, the libraries around Groovy will also drop. Also, if you don't have spock-spring, you can't use @Autowired etc. in Spock (Groovy), so add this if necessary.

pom.xml

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-test</artifactId>
	<scope>test</scope>
</dependency>
<dependency>
	<groupId>org.spockframework</groupId>
	<artifactId>spock-core</artifactId>
	<version>1.2-groovy-2.5</version>
	<scope>test</scope>
</dependency>
<dependency>
	<groupId>org.spockframework</groupId>
	<artifactId>spock-spring</artifactId>
	<version>1.2-groovy-2.5</version>
	<scope>test</scope>
</dependency>

The URL and response body of the RestController you want to test

The URL and response body of the RestController you want to test are as follows.

URL：
  http://localhost:8080/employees

Response：
  Status Code 200 OK
  [
    {
      "id": "00000001",
      "name": "Employee A",
      "department": {
        "id": "001",
        "name": "Department A"
      }
    },
    {
      "id": "00000002",
      "name": "Employee B",
      "department": {
        "id": "001",
        "name": "Department A"
      }
    }
  ]

Controller class you want to test

I will omit the steps from EmployeeService # getEmployees, but the Controller you want to test is as follows.

EmployeeController.java

@RestController
public class EmployeeController {

	@Autowired
	private EmployeeService employeeService;

	@GetMapping(value = "/employees")
	public ResponseEntity<List<Employee>> getEmployees() {
		List<Employee> employeeList = employeeService.getEmployees();
		if (CollectionUtils.isEmpty(employeeList)) {
			return new ResponseEntity<>(null, HttpStatus.NO_CONTENT);	
		}
		return new ResponseEntity<List<Employee>>(employeeList, HttpStatus.OK);
	}
}

Test class

Verify using Groovy's Json Slurper and Json Builder.

• When using MockMvc in Spring Boot test, assign @AutoConfigureMockMvc to the test class. Doing so will allow @Autowired to inject MockMvc.
• As a second test case, I will write a case where nothing is set in the response body. Therefore, only in that case, @SpyBean is used to spy EmployeeService # getEmployees to return null (because @MockBean is also used to Mock EmployeeService in Case 1).
• If @SpringBootTest is added, the server will not start by default. Therefore, if you want to flexibly deal with that, you will use the webEnvironment attribute (not used in this example).

//ApplicationContext is loaded, but Web environment etc. is not provided
@SpringBootTest(webEnvironment = WebEnvironment.NONE)

//Start the server on a random port
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)


//The default is this, you don't have to write it. A simulated web environment is provided without starting the server
// @AutoConfigureMockMvc or@Can be used in combination with AutoConfigureWebTestClient
@SpringBootTest(webEnvironment = WebEnvironment.MOCK)


//The actual web environment is provided. The embedded server starts and the configured port (application).Listen on properties) or on the default port 8080
@SpringBootTest(webEnvironment = WebEnvironment.DEFINED_PORT)

EmployeeControllerTest.groovy

@SpringBootTest
@AutoConfigureMockMvc
class EmployeeControllerTest extends Specification {

	@SpyBean
	private EmployeeService employeeService

	@Autowired
	MockMvc mockMvc

	@Unroll
	def "EmployeeController -Normal system-2 employees return"() {

		given:
		def department = new Department("001", "Department A");
		def employeeList = new ArrayList<Employee>() { {
						this.add(new Employee("00000001", "Employee A", department));
						this.add(new Employee("00000002", "Employee B", department));
					}
				}
		def jsonBuilder = new JsonBuilder(employeeList)
		def jsonSlurper = new JsonSlurper()

		when:
		def actual = mockMvc.perform(MockMvcRequestBuilders.get("/employees")).andReturn().getResponse()

		then:
		actual.getStatus() == HttpStatus.OK.value
		jsonSlurper.parseText(actual.getContentAsString()) == jsonSlurper.parseText(jsonBuilder.toPrettyString())
	}

	@Unroll
	def "EmployeeController -Normal system-Nothing returns"() {

		given:
		when(employeeService.getEmployees()).thenReturn(null)

		when:
		def actual = mockMvc.perform(MockMvcRequestBuilders.get("/employees")).andReturn().getResponse()

		then:
		actual.getStatus() == HttpStatus.NO_CONTENT.value
		actual.getContentAsString() == ""
	}
}

In this article, I used Groovy's Json Slurper and Json Builder to verify JSON. Alternatively, [Spring Boot @JsonTest](https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-testing.html#boot-features-testing-spring You can also verify JSON by using -boot-applications-testing-autoconfigured-json-tests) etc.

Source used in this article: https://github.com/kenichi-nagaoka/spock-sample/tree/feature/1

that's all.

reference

• https://spock-framework-reference-documentation-ja.readthedocs.io/ja/latest/index.html