Quarkus testing using @QuarkusTest, mocks and javax.enterprise.inject.Instance

Question

We have an application that uses javax.enterprise.inject.Instance to find all validators for a service. This seems to work nicely but during testing we would like to swap out a few of those validators with a mock to skip their behaviour so it's easier to reach other validators.

When we try to do this using the 'Old approach' (See Blog-post on this) we notice only the classes with @Mock are injected, not any of the normal ones.

When trying it the 'New approach' we get a javax.enterprise.inject.AmbiguousResolutionException that tells us TypeBValidator is found twice.

This is the setup of a trimmed-down version of our app showing the behaviour:

• Validator-interface
• TypeAValidator (@ApplicationScoped)
• TypeBValidator (@ApplicationScoped)
• REST-Service-class that has a @Inject like this: Instance<Validator> validators via the constructor.

In test-scope we have:

• TypeBMockValidator (which does have @Mock in old and no @Mock in the new approach)
• Test class for REST-Service that is annotated with @QuarkusTest. This test-class calls the REST-service using restassured, right as it's provided when one generates an example project.

See the example project for all details.

I'm looking for a stable and predictable way to replace only the TypeBValidator during my tests. Any help would be highly appreciated.

Answer 1

Turns out that this was not a bug, but the expected behavior of CDI when multiple there is a class hierarchy where multiple classes are beans. In this case, the simplest solution is to annotate TypeBValidator with @DefaultBean.

See https://github.com/quarkusio/quarkus/issues/19773#issuecomment-909974623 for more details