How to write JUnit test cases for a SpringBoot Application which does not have @SpringBootApplication?

Question

I have 2 SpringBoot separate applications created Core Project and Rest Project.

1. Core Project :- Has the services for the CRUD operations called from from Rest Project.

2. Rest Project :- Which has the @SpringBootApplication which calls the Core Project services from the controller.

Note: Core project is added as a dependency to Rest Project.

I want to write testcases for the core project .

While creating the JUNit tests I am getting this error in JUnit:

• org.springframework.boot.test.context.SpringBootTestContextBootstrapper -> Neither @ContextConfiguration nor @ContextHierarchy found for test class core.repository.SampleRepositoryTests, using SpringBootContextLoader

• DEBUG org.springframework.test.context.support.AbstractContextLoader -> Did not detect default resource location for test class core.repository.SampleRepositoryTests: class path resource core/repository/SampleRepositoryTests-context.xml does not exist

• DEBUG org.springframework.test.context.support.AbstractContextLoader -> Did not detect default resource location for test class core.repository.SampleRepositoryTests: class path resource core/repository/SampleRepositoryTestsContext.groovy] does not exist

• INFO org.springframework.test.context.support.AbstractContextLoader -> Could not detect default resource locations for test class core.repository.SampleRepositoryTests]: no resource found for suffixes {-context.xml, Context.groovy}.

• INFO org.springframework.test.context.support.AnnotationConfigContextLoaderUtils -> Could not detect default configuration classes for test class core.repository.SampleRepositoryTests: ProjectRepositoryTests does not declare any static, non-private, non-final, nested classes annotated with @Configuration.

• DEBUG org.springframework.test.context.support.ActiveProfilesUtils -> Could not find an 'annotation declaring class' for annotation type [org.springframework.test.context.ActiveProfiles] and class core.repository.SampleRepositoryTests

The stack trace is:

 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:393)
    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.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTestContextManager(SpringJUnit4ClassRunner.java:151)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.<init>(SpringJUnit4ClassRunner.java:142)
    at org.springframework.test.context.junit4.SpringRunner.<init>(SpringRunner.java:49)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:64)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
    at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
    at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:33)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createUnfilteredTest(JUnit4TestLoader.java:90)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:76)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:49)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:525)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:768)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:464)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:210)

For reference :- I found a similar scenario https://www.baeldung.com/spring-boot-unable-to-find-springbootconfiguration-with-datajpatest#missing-springbootconfiguration , but same error is coming when configuring similarly.

Answer 1

I'm guessing you annotated your junit test class with @RunWith(SpringRunner.class).

That initializes the Spring context but does not configure and add any beans to it. So if you will try to @Authowire or use any other Spring functionality, it will fail.

You have two options here:

1. Configure and add bean that you are testing (for example, MyService) by adding @ContextConfiguration(classes = MyService.class) or @SpringBootTest(classes=MyService.class) or by providing test configuration as described here, for example: https://www.baeldung.com/spring-boot-testing
2. Remove @RunWith(SpringRunner.class) annotation and create instance of the class you will be testing manually, via new. But this is not preferable options, it will not autocreate mocks etc...