testcontainer

在我們的項目中，單元測試是保證我們代碼質量非常重要的一環，但是我們的業務代碼不可避免的需要依賴外部的系統或服務如DB，redis，其他外部服務等。如何保證我們的測試代碼不受外部依賴的影響，能夠穩定的運行成為了一件比較讓人頭疼的事情。

mock

通過mockito等框架，可以模擬外部依賴各類組件的返回值，通過隔離的方式穩定我們的單元測試。但是這種方式也會帶來以下問題：

測試代碼冗長難懂，因為要在測試中模擬各類返回值，一行業務代碼往往需要很多測試代碼來支撐
無法真實的執行SQL腳本
僅僅適用于單元測試，對于端到端的測試無能為力

testcontainer

testcontainer，人如其名，可以在啟動測試時，創建我們所依賴的外部容器，在測試結束時自動銷毀，通過容器的技術來達成測試環境的隔離。

目前testcontainer僅支持docker，使用testcontainer需要提前安裝docker環境

簡單的例子

假設我們有一個springboot的web項目，在這個項目中使用postgresql作為數據庫
首先我們將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>

然后是我們的entity對象和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> {
}

最后是我們的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，我們通過src/resources/schema.sql來進行表的初始化，在正常項目中應該通過flyway等進行數據庫的管理

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

最后是重頭戲，如果通過testcontainer來完成我們的端到端測試

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”
);`

這里創建了一個postgres的容器，然后通過 @DynamicPropertySource為spring.datasource的各項參數賦值，剩下的就由Spring的auto-configure完成各類bean的自動裝配，JPA的裝配和注入。

除了通過 @DynamicPropertySource外，spring-boot-testcontainers提供了一些方法可以更加簡化這個流程
首先添加依賴

		<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注解會幫助我們在測試開始前啟動容器，在測試結束后停止容器，因此我們可以省略@BeforeAll和@AfterAll

@ServiceConnection取代了 @DynamicPropertySource中代碼的功能，幫助我們完成bean的創建

除此之外，我們也可以通過@bean的方式來創建容器

@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");}}
}

連接web服務

PostgreSQLContainer是一個專門用于連接PostgreSQL的類，除此之外testcontainer還提供了redis、mysql、es、kafka等常用中間件的容器類。如果我們想要去連接一個內部的web服務，那該怎么做？

首先，我們要確保該服務已經容器化，可以直接通過docker來啟動，其次，testcontainer提供了一個公共的GenericContainer來處理這類場景，

假設我們有一個服務鏡像demo/demo:latest，該服務暴露了一個8080端口，我們通過feignclient來訪問

@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());}}