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  1. Jenkins
  2. JENKINS-41827

JenkinsRule mode to use realistic class loading


      JenkinsRule-based tests generally load not only Jenkins core but also all plugins from ${java.class.path}, i.e., the Maven test-scoped classpath. This is convenient in some ways but also means that class loading is done in a very different way than in an actual production instance, or even mvn hpi:run, making it very hard to test changes like JENKINS-26192 without using the much clunkier, slower, and flakier acceptance-test-harness. It also means that we are forever fighting with Maven's weird transitive dependency management (JENKINS-41631, JENKINS-39301, etc.).

      There should be an option to run JenkinsRule in a mode whereby the test classpath is only used to load Jetty; Jenkins core and its WEB-INF/lib/*.jar (including modules!) is loaded in a derivative class loader; and then plugins are discovered from the test classpath, transitive dependencies computed and verified, and finally loaded in the real plugin class loader (probably using *.jpl files to allow us to still load from unpacked development trees). Finally, the test suite itself needs to be reloaded in a fresh loader parented to UberClassLoader, and executed from there.

      NbModuleSuite demonstrates the concept, though the details would be rather different for Jenkins.

      There are a lot of details to be checked, such as

      • @TestExtension handling
      • PluginWorkspaceMap support for co√∂rdinated snapshot development
      • moving InjectedTest from HudsonTestCase so that it can use the new mode

            jglick Jesse Glick
            jglick Jesse Glick
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