Allow using @ApplicationModuleTest outside of a module package

[odrotbohm]

Discussed in #413

^{Originally posted by marinusgeuze December 11, 2023}
Hi,

In our project, we have organized our tests into different root packages based on their types, such as unit tests, integration tests, and end-to-end tests. Consequently, our Spring Boot Integration Tests are placed in a package different from their corresponding modules, leading to the occurrence of the “Package %s is not part of any module!” error.

To provide more context, our test package structure looks something like this:

unit.com.test..*UnitTest
it.com.test..*IntegrationTest
end2end.com.test..*End2EndTest

We are seeking a solution to explicitly define the module to which a Spring Boot Integration Test belongs. This as part of the ApplicationModuleTest annotation. Or ideally, we would like to add the it.com.test package to the module. Is there a way to achieve this?

We acknowledge that a possible recommendation might be to group tests within the module boundaries, like com.test..unit.*UnitTest, com.test..it.*IntegrationTest, etc. However, this is not a feasible option for us due to the configuration constraints of our test frameworks.

[odrotbohm]

We could / would need to add the following attributes to @ApplicationModuleTest:

• module (String) – the logical name of the module to bootstrap
• classes (alias of @SpringBootTest(classes) – to explicitly point to the main application class

ModuleTestExecution would need to be altered to skip the module detection in case module is configured. Furthermore, we'd have to inspect the classes manually configured for a @SpringBootApplication annotation to detect the primary application class before falling back to the lookup via a package traversal.

[lukasdo]

@odrotbohm can I draft a PR for this issue?