[spring error] Unable to find a @SpringBootConfiguration

spring에서 Unable to find a @SpringBootConfiguration가 발생할 때 에러.

나 같은 경우는 multi module project를 구성할 때 에러 메세지가 나왔다.
multi module에서 library module과 project module을 나눠서 구성할 때.

에러 메세지

java.lang.IllegalStateException: Unable to find a @SpringBootConfiguration, you need to use @ContextConfiguration or @SpringBootTest(classes=...) with your test

	at org.springframework.util.Assert.state(Assert.java:76)
	at org.springframework.boot.test.context.SpringBootTestContextBootstrapper.getOrFindConfigurationClasses(SpringBootTestContextBootstrapper.java:236)
	at org.springframework.boot.test.context.SpringBootTestContextBootstrapper.processMergedContextConfiguration(SpringBootTestContextBootstrapper.java:152)
	at org.springframework.test.context.support.AbstractTestContextBootstrapper.buildMergedContextConfiguration(AbstractTestContextBootstrapper.java:392)
	at org.springframework.test.context.support.AbstractTestContextBootstrapper.buildDefaultMergedContextConfiguration(AbstractTestContextBootstrapper.java:309)
	at org.springframework.test.context.support.AbstractTestContextBootstrapper.buildMergedContextConfiguration(AbstractTestContextBootstrapper.java:262)
	at org.springframework.test.context.support.AbstractTestContextBootstrapper.buildTestContext(AbstractTestContextBootstrapper.java:107)
	at org.springframework.boot.test.context.SpringBootTestContextBootstrapper.buildTestContext(SpringBootTestContextBootstrapper.java:102)
	at org.springframework.test.context.TestContextManager.<init>(TestContextManager.java:137)
	at org.springframework.test.context.TestContextManager.<init>(TestContextManager.java:122)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore.lambda$getOrComputeIfAbsent$4(ExtensionValuesStore.java:86)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$MemoizingSupplier.computeValue(ExtensionValuesStore.java:223)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$MemoizingSupplier.get(ExtensionValuesStore.java:211)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$StoredValue.evaluate(ExtensionValuesStore.java:191)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$StoredValue.access$100(ExtensionValuesStore.java:171)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore.getOrComputeIfAbsent(ExtensionValuesStore.java:89)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore.getOrComputeIfAbsent(ExtensionValuesStore.java:93)
	at org.junit.jupiter.engine.execution.NamespaceAwareStore.getOrComputeIfAbsent(NamespaceAwareStore.java:61)
	at org.springframework.test.context.junit.jupiter.SpringExtension.getTestContextManager(SpringExtension.java:294)
	at org.springframework.test.context.junit.jupiter.SpringExtension.beforeAll(SpringExtension.java:113)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeBeforeAllCallbacks$10(ClassBasedTestDescriptor.java:381)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.invokeBeforeAllCallbacks(ClassBasedTestDescriptor.java:381)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.before(ClassBasedTestDescriptor.java:205)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.before(ClassBasedTestDescriptor.java:80)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:148)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:107)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86)
	at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86)
	at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:53)
	at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:71)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:220)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:53)

코드

spring에서 multi module 이슈라면 kotlin인지 java인지는 중요하지 않다.

@ExtendWith(SpringExtension::class)
@SpringBootTest
class JpaRepositoryTest {

    @Autowired
    lateinit var sut: MysqlJpaRepository

	...
}

해결

@ExtendWith(SpringExtension::class)
@Import(TestConfig::class)
@SpringBootTest
class JpaRepositoryTest {

    @SpringBootConfiguration
    @ComponentScan("com.meansoup") // 여기는 base package name
    class TestConfig

    @Autowired
    lateinit var sut: MysqlJpaRepository

	...
}

원인

library가 되는 모듈에는 @SpringBootApplication이 없다.
따라서 @SpringBootConfiguration도 없는데 그렇기 때문에 bean이 있다는 것을 알지 못한다.

위와 같이 테스트에서 @SpringBootConfiguration를 명시해주므로써 bean을 인지하고 사용할 수 있다.

reference

https://github.com/spring-guides/gs-multi-module

위 프로젝트의 코드를 확인

https://www.baeldung.com/springbootconfiguration-annotation

SpringBootConfiguration에 대해