Spring为每个单元测试文件加载上下文

Question

我有 16 个单元测试用例文件。每个都采用这种格式：

@SpringBootTest
class UserServiceTest {

  @Autowired
  UserService userService;

  @MockBean
  SomeDependency someDependency;

  @Test
  ...and so on

}

每当我运行 mvn clean install 时，似乎 spring 正在重新启动/加载上下文 16 次。我看到这些日志 16 次：

[INFO] Running com.base.UserServiceTest
2021-07-16 04:35:39.421 [INFO ] [main] o.s.t.c.s.AbstractTestContextBootstrapper - Neither @ContextConfiguration nor @ContextHierarchy found for test class [com.base.UserServiceTest], using SpringBootContextLoader
2021-07-16 04:35:39.423 [INFO ] [main] o.s.t.c.s.AbstractContextLoader - Could not detect default resource locations for test class [com.base.UserServiceTest]: no resource found for suffixes {-context.xml, Context.groovy}.
2021-07-16 04:35:39.424 [INFO ] [main] o.s.t.c.s.AnnotationConfigContextLoaderUtils - Could not detect default configuration classes for test class [com.base.UserServiceTest]: UserServiceTest does not declare any static, non-private, non-final, nested classes annotated with @Configuration.
2021-07-16 04:35:39.473 [INFO ] [main] o.s.b.t.c.SpringBootTestContextBootstrapper - Found @SpringBootConfiguration com.base.Application for test class com.base.UserServiceTest
2021-07-16 04:35:39.475 [INFO ] [main] o.s.t.c.s.AbstractTestContextBootstrapper - Loaded default TestExecutionListener class names from location [META-INF/spring.factories]: [org.springframework.boot.test.mock.mockito.MockitoTestExecutionListener, org.springframework.boot.test.mock.mockito.ResetMocksTestExecutionListener, org.springframework.boot.test.autoconfigure.restdocs.RestDocsTestExecutionListener, org.springframework.boot.test.autoconfigure.web.client.MockRestServiceServerResetTestExecutionListener, org.springframework.boot.test.autoconfigure.web.servlet.MockMvcPrintOnlyOnFailureTestExecutionListener, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverTestExecutionListener, org.springframework.boot.test.autoconfigure.webservices.client.MockWebServiceServerTestExecutionListener, org.springframework.test.context.web.ServletTestExecutionListener, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener, org.springframework.test.context.event.ApplicationEventsTestExecutionListener, org.springframework.test.context.support.DependencyInjectionTestExecutionListener, org.springframework.test.context.support.DirtiesContextTestExecutionListener, org.springframework.test.context.transaction.TransactionalTestExecutionListener, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener, org.springframework.test.context.event.EventPublishingTestExecutionListener]
2021-07-16 04:35:39.476 [INFO ] [main] o.s.t.c.s.AbstractTestContextBootstrapper - Using TestExecutionListeners: [org.springframework.test.context.web.ServletTestExecutionListener@4dc599a7, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener@635f2d9b, org.springframework.test.context.event.ApplicationEventsTestExecutionListener@7e83380f, org.springframework.boot.test.mock.mockito.MockitoTestExecutionListener@6000fc20, org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener@1e95926, org.springframework.test.context.support.DirtiesContextTestExecutionListener@1bc08f75, org.springframework.test.context.transaction.TransactionalTestExecutionListener@7ce49f42, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener@1b629d02, org.springframework.test.context.event.EventPublishingTestExecutionListener@5089c721, org.springframework.boot.test.mock.mockito.ResetMocksTestExecutionListener@4fad5162, org.springframework.boot.test.autoconfigure.restdocs.RestDocsTestExecutionListener@176bd95a, org.springframework.boot.test.autoconfigure.web.client.MockRestServiceServerResetTestExecutionListener@186edc38, org.springframework.boot.test.autoconfigure.web.servlet.MockMvcPrintOnlyOnFailureTestExecutionListener@6c0b0db, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverTestExecutionListener@2343c720, org.springframework.boot.test.autoconfigure.webservices.client.MockWebServiceServerTestExecutionListener@6aab6b1b]

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.5.0)

2021-07-16 04:35:39.520 [INFO ] [main] o.s.b.StartupInfoLogger - Starting UserServiceTest using Java 11.0.2 on 
2021-07-16 04:35:39.523 [INFO ] [main] o.s.b.SpringApplication - The following profiles are active: local
2021-07-16 04:35:40.197 [INFO ] [main] o.s.m.w.MockServletContext - Initializing Spring TestDispatcherServlet ''
2021-07-16 04:35:40.197 [INFO ] [main] o.s.w.s.FrameworkServlet - Initializing Servlet ''
2021-07-16 04:35:40.199 [INFO ] [main] o.s.w.s.FrameworkServlet - Completed initialization in 1 ms
2021-07-16 04:35:40.211 [INFO ] [main] o.s.b.StartupInfoLogger - Started UserServiceTest in 0.732 seconds (JVM running for 9.613)
[INFO] Tests run: 3, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.918 s - in com.base.UserServiceTest

这会导致两个问题：

1. 还有很多测试要添加。即使有 16 个测试文件，执行也需要大约 20 秒。所以这个过程很慢。
2. 我的应用程序使用 JPA 连接 DB，在mvn clean install 期间，虽然应用程序构建成功，但它在日志中随机出现此错误的次数：

2021-07-16 04:35:52.741 [ERROR] [main] c.z.h.p.HikariPool - HikariPool-11 - Exception during pool initialization. org.postgresql.util.PSQLException: FATAL: remaining connection slots are reserved for non-replication superuser connections

我想知道当我经常执行mvn clean install 时，这种上下文重新加载是否会导致这种情况，并且某处可能存在连接泄漏。

使用 JUnit 5/Jupiter 和 Spring 5。

感谢您在修复以上 2 点方面的任何帮助。谢谢。

Answer 1

Spring Test caches your TestContext 并在上下文配置适合时将其重新用于另一个测试。

但是，如果您的所有测试都具有不同的设置（例如，第一个测试需要 A 类的模拟版本，而第二个测试需要 B 类的模拟版本），缓存将无济于事，Spring 必须启动一个新的上下文。

如果您简化所有测试的上下文设置，Spring 将重用它，从而加快测试执行速度。

此外，您添加的测试（使用 @SpringBootTest）不是单元测试（嗯 - 它始终取决于定义），因为它启动了整个 Spring 上下文。

如果您的计划是为您的业务逻辑编写单元测试，最好只使用 JUnit 5 和 Mockito。这些测试很快，并且没有 Spring 支持，因此没有启动上下文。

有关 Spring Boot 应用程序的单元、集成和端到端测试策略的广泛概述，请查看article。