testcontainer

在我们的项目中，单元测试是保证我们代码质量非常重要的一环，但是我们的业务代码不可避免的需要依赖外部的系统或服务如DB，redis，其他外部服务等。如何保证我们的测试代码不受外部依赖的影响，能够稳定的运行成为了一件比较让人头疼的事情。

mock

通过mockito等框架，可以模拟外部依赖各类组件的返回值，通过隔离的方式稳定我们的单元测试。但是这种方式也会带来以下问题：

测试代码冗长难懂，因为要在测试中模拟各类返回值，一行业务代码往往需要很多测试代码来支撑
无法真实的执行SQL脚本
仅仅适用于单元测试，对于端到端的测试无能为力

testcontainer

testcontainer，人如其名，可以在启动测试时，创建我们所依赖的外部容器，在测试结束时自动销毁，通过容器的技术来达成测试环境的隔离。

目前testcontainer仅支持docker，使用testcontainer需要提前安装docker环境

简单的例子

假设我们有一个springboot的web项目，在这个项目中使用postgresql作为数据库
首先我们将testcontainer添加到pom.xml中

<dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.postgresql</groupId><artifactId>postgresql</artifactId><scope>runtime</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>org.testcontainers</groupId><artifactId>junit-jupiter</artifactId><scope>test</scope></dependency><dependency><groupId>org.testcontainers</groupId><artifactId>postgresql</artifactId><scope>test</scope></dependency><dependency><groupId>io.rest-assured</groupId><artifactId>rest-assured</artifactId><scope>test</scope></dependency></dependencies>

然后是我们的entity对象和Repository

@Entity
@Table(name = "customers")
public class Customer {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private Long id;@Column(nullable = false)private String name;@Column(nullable = false, unique = true)private String email;public Customer() {}public Customer(Long id, String name, String email) {this.id = id;this.name = name;this.email = email;}public Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}
}

public interface CustomerRepository extends JpaRepository<Customer, Long> {
}

最后是我们的controller

@RestController
public class CustomerController {private final CustomerRepository repo;CustomerController(CustomerRepository repo) {this.repo = repo;}@GetMapping("/api/customers")List<Customer> getAll() {return repo.findAll();}
}

由于是demo，我们通过src/resources/schema.sql来进行表的初始化，在正常项目中应该通过flyway等进行数据库的管理

create table if not exists customers (id bigserial not null,name varchar not null,email varchar not null,primary key (id),UNIQUE (email)
);

并在application.properties中添加如下配置

spring.sql.init.mode=always

最后是重头戏，如果通过testcontainer来完成我们的端到端测试

import static io.restassured.RestAssured.given;
import static org.hamcrest.Matchers.hasSize;import com.example.testcontainer.domain.Customer;
import com.example.testcontainer.repo.CustomerRepository;
import io.restassured.RestAssured;
import io.restassured.http.ContentType;
import java.util.List;
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.BeforeEach;
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.web.server.LocalServerPort;
import org.springframework.test.context.DynamicPropertyRegistry;
import org.springframework.test.context.DynamicPropertySource;
import org.testcontainers.containers.PostgreSQLContainer;@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class CustomerControllerTest {@LocalServerPortprivate Integer port;static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:14");@BeforeAllstatic void beforeAll() {postgres.start();}@AfterAllstatic void afterAll() {postgres.stop();}@DynamicPropertySourcestatic void configureProperties(DynamicPropertyRegistry registry) {registry.add("spring.datasource.url", postgres::getJdbcUrl);registry.add("spring.datasource.username", postgres::getUsername);registry.add("spring.datasource.password", postgres::getPassword);}@AutowiredCustomerRepository customerRepository;@BeforeEachvoid setUp() {RestAssured.baseURI = "http://localhost:" + port;customerRepository.deleteAll();}@Testvoid shouldGetAllCustomers() {List<Customer> customers = List.of(new Customer(null, "John", "john@mail.com"),new Customer(null, "Dennis", "dennis@mail.com"));customerRepository.saveAll(customers);given().contentType(ContentType.JSON).when().get("/api/customers").then().statusCode(200).body(".", hasSize(2));}
}

static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>(
“postgres:14”
);`

这里创建了一个postgres的容器，然后通过 @DynamicPropertySource为spring.datasource的各项参数赋值，剩下的就由Spring的auto-configure完成各类bean的自动装配，JPA的装配和注入。

除了通过 @DynamicPropertySource外，spring-boot-testcontainers提供了一些方法可以更加简化这个流程
首先添加依赖

		<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-testcontainers</artifactId><scope>test</scope></dependency>

@Testcontainers
@SpringBootTest
public class MyIntegrationServiceConnectionTests {@Container@ServiceConnectionstatic PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:14");@AutowiredCustomerRepository customerRepository;@Testvoid shouldGetAllCustomers() {List<Customer> customers = List.of(new Customer(null, "John", "john@mail.com"),new Customer(null, "Dennis", "dennis@mail.com"));customerRepository.saveAll(customers);assertTrue(customerRepository.findByName("John").isPresent());assertEquals(2,customerRepository.findAll().size());}
}

@Testcontainers注解会帮助我们在测试开始前启动容器，在测试结束后停止容器，因此我们可以省略@BeforeAll和@AfterAll

@ServiceConnection取代了 @DynamicPropertySource中代码的功能，帮助我们完成bean的创建

除此之外，我们也可以通过@bean的方式来创建容器

@Testcontainers
@SpringBootTest
public class MyIntegrationBeanConfiguratonTests {@AutowiredCustomerRepository customerRepository;@Testvoid shouldGetAllCustomers() {List<Customer> customers = List.of(new Customer(null, "John", "john@mail.com"),new Customer(null, "Dennis", "dennis@mail.com"));customerRepository.saveAll(customers);assertTrue(customerRepository.findByName("John").isPresent());assertEquals(2,customerRepository.findAll().size());}@TestConfiguration(proxyBeanMethods = false)public  static class MyPostgreConfiguration {@Bean@ServiceConnectionpublic PostgreSQLContainer<?> postgreSQLContainer() {return new PostgreSQLContainer<>("postgres:14");}}
}

连接web服务

PostgreSQLContainer是一个专门用于连接PostgreSQL的类，除此之外testcontainer还提供了redis、mysql、es、kafka等常用中间件的容器类。如果我们想要去连接一个内部的web服务，那该怎么做？

首先，我们要确保该服务已经容器化，可以直接通过docker来启动，其次，testcontainer提供了一个公共的GenericContainer来处理这类场景，

假设我们有一个服务镜像demo/demo:latest，该服务暴露了一个8080端口，我们通过feignclient来访问

@FeignClient(name = "customFeign",url = "${remote.custom.url}")
public interface ExternalCustomClient {@GetMapping("custom/{id}")public CustomInfo getCustom(@PathVariable("id") String id);
}

@Testcontainers
@SpringBootTest
public class ExternalCustomClientTest {@Containerstatic GenericContainer<?> container = new GenericContainer<>("demo/demo:latest").withExposedPorts(8080);@DynamicPropertySourcestatic void configureProperties(DynamicPropertyRegistry registry) {Integer firstMappedPort = container.getMappedPort(8080);String ipAddress = container.getHost();System.out.println(ipAddress);System.out.println(firstMappedPort);registry.add("remote.custom.url",() -> "http://"+ipAddress+":"+firstMappedPort);}@AutowiredExternalCustomClient customClient;@Testvoid shouldGetAllCustomers() {String id ="111";CustomInfo customInfo=customClient.getCustom(id);Assertions.assertEquals(id, customInfo.getCustomNo());}}