CAMEL-22891: refactoring IT using JUnit

[mcarlett]

Refactors completely the integration tests moving from arquillian to junit, instead of creating the application to test at runtime using shrinkwrap, it uses the maven archetype. Following a part of the included readme file, to overview the steps of each test

. Archetype generation -- The ArchetypeGenerationExtension JUnit 6 extension generates a minimal Spring Boot project from camel-archetype-spring-boot. The generated project is then customized: test-scoped dependencies and the demo camel-stream-starter are removed, the starter under test is added, and any extra dependencies or application.properties entries from the test config are applied.
. Compilation -- The generated project is compiled via mvn compile dependency:build-classpath, which also writes the full runtime classpath to a file for the next step.
. Classloader isolation -- A child URLClassLoader is created with the compiled classes and all resolved dependency JARs, parented by the test classloader. Only camel-api and spring-context live on the parent classloader so that assertion types (CamelContext, Component, DataFormat, Language, CamelClusterService) are shared.
. Spring Boot startup -- SpringApplication is loaded from the child classloader and started via reflection. A DefaultResourceLoader pointing at the child classloader ensures the generated project's application.properties is picked up. By default, the embedded web server is disabled (spring.main.web-application-type=none). When webRequired is set to true, the web stack is kept and the server binds to a random port (server.port=0) to avoid conflicts during parallel execution.

[Croway]

please move the non test classes under src/main like it was before

[Croway]

is there some automation that create ITs? I remember I saw something in the past, some .sh but I might be wrong

[mcarlett]

there is not an automation currently, but this is useful to start implementing new tests, so I added a maven execution that is more portable than a bash script

mvn -Pgenerate -Dstarter=my-component -pl tests/camel-itest-spring-boot

[mcarlett]

please move the non test classes under src/main like it was before

done

[Croway]

merging, let's check https://ci-builds.apache.org/job/Camel/job/Camel-Spring-Boot%20Daily%20JDK17/ tomorrow