Document how to configure Maven's Failsafe plugin when not using spring-boot-starter-parent

While migrating an existing application from 2.3.7.RELEASE to 2.4.3 I faced an issue running integration tests complaining with:

java.lang.IllegalStateException: Failed to find merged annotation for @org.springframework.test.context.BootstrapWith(value=org.springframework.boot.test.context.SpringBootTestContextBootstrapper.class)

Find attached a very simple & minimal reproducer case.

Steps

Preparation

spring-reproducer.zip

• unzip spring-reproducer.zip
• cd spring-reproducer

OK with 2.3.7.RELEASE

• mvn clean verify

Failing with 2.4.3

• mvn -Dspring-boot.version=2.4.3 clean verify

using this version of spring-boot the build fails showing the following details in the failsafe-report

-------------------------------------------------------------------------------
Test set: com.lectra.spring.ApplicationLoaderTestIT
-------------------------------------------------------------------------------
Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.136 s <<< FAILURE! - in com.lectra.spring.ApplicationLoaderTestIT
com.lectra.spring.ApplicationLoaderTestIT  Time elapsed: 0.136 s  <<< ERROR!
java.lang.IllegalStateException: Failed to find merged annotation for @org.springframework.test.context.BootstrapWith(value=org.springframework.boot.test.context.SpringBootTestContextBootstrapper.class)

[sbrannen]

This might be due because of some classloading differences appearing only via failsafe.

It turns out that is indeed the case.

After some debugging and a follow-up brainstorming session with @wilkinsona, we’ve determined that this is effectively a duplicate of https://github.com/spring-projects/spring-boot/issues/6254.

The fact that you resorted to the following should have been an indicator that something was wrong with the classpath.

@SpringBootTest(classes = ErrorReproducerApplication.class)

In a properly structured Spring Boot project, an empty @SpringBootTest declaration should suffice: Spring Boot Test will find your @SpringBootApplication class automatically.

The reason your Maven Failsafe configuration is not working is two-fold.

1. When using JDK 11, Failsafe is putting the repackaged (by Boot) application JAR on the module-path: <property name="jdk.module.path" value="/path/to/project/target/MyApplication.jar"/>.
2. When using Failsafe with Spring Boot, Failsafe will by default put the repackaged (by Boot) application JAR on the classpath.

To fix problem # 1, you need to add the following to the <configuration> section of the maven-failsafe-plugin:

<useModulePath>false</useModulePath>

To fix problem # 2, you have some options

1. https://github.com/spring-projects/spring-boot/issues/6254#issuecomment-229600830
2. https://github.com/spring-projects/spring-boot/issues/6254#issuecomment-343470070
3. https://github.com/spring-projects/spring-boot/issues/6254#issuecomment-281404852

I went with option # 3 above and combined that with the first fix, ending up with the following in the <configuration> section of the maven-failsafe-plugin.

<useModulePath>false</useModulePath>
<additionalClasspathElements>
	<additionalClasspathElement>${basedir}/target/classes</additionalClasspathElement>
</additionalClasspathElements>

After that, both test classes pass with the Surefire and Failsafe plugins, respectively.

In light of that, I think this issue should be transferred to Spring Boot to improve the documentation.

p.s. @wilkinsona mentioned that these issues may not have manifested if the project’s POM inherited from the Spring Boot parent POM, but I’ll let him expound on that.

[wilkinsona]

Thanks, @sbrannen.

spring-boot-starter-parent configures some defaults for Failsafe. Specifically, it configures the <classesDirectory> to be ${project.build.outputDirectory}. I think we should consider documenting this somewhere for the benefit of users whose Maven projects don’t use spring-boot-starter-parent.