Introduce a new JCasC Test Harness Library

[oleg-nenashev]

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• Link to any upstream changes that might be required (for example Jenkins Core pull request)

Feature Request

It looks like we have a lot of test framework functionality for JCasC:

• https://github.com/jenkinsci/configuration-as-code-plugin/blob/master/plugin/src/test/java/io/jenkins/plugins/casc/misc/JenkinsConfiguredWithCodeRule.java and dependencies
• Roundtrip tests from @MRamonLeon : [JENKINS-57761] - Add abstract test for export/configure roundtrip #908
• WiP - JCasC support in the Plugin benchmarking support by @AbhyudayaSharma: [JENKINS-57653] Introduce JMH benchmarks to Jenkins Test Harness jenkins-test-harness#135

Currently it is hard to reuse this code, because it is located within the test suites, so an odd dependency is needed. Also, it makes the downstream plugins to pull in more test dependencies than we really want.

    <dependency>
      <groupId>io.jenkins</groupId>
      <artifactId>configuration-as-code</artifactId>
      <version>${configuration-as-code.version}</version>
      <classifier>tests</classifier>
      <scope>test</scope>
    </dependency>

What if we introduce a new configuration-as-code-test-harness component which would ship it in a library?

    <dependency>
      <groupId>io.jenkins</groupId>
      <artifactId>configuration-as-code-test-harness</artifactId>
      <version>${configuration-as-code.version}</version>
      <scope>test</scope>
    </dependency>

[timja]

Yes, I believe we discussed it before, last time there was a packaging issue with the test classifier, we did the quick fix at the time but a separate module would be good in my opinion

[MRamonLeon]

LGTM ❤️

[timja]

resolved in #1215

[oleg-nenashev]

I believe it is fixed by @timja in #1215

[oleg-nenashev]

ERR_RACE_CONDITION