Consider running assemble instead of -x test build by default

[jonatan-ivanov]

The default value of BP_GRADLE_BUILD_ARGUMENTS currently is --no-daemon -x test build. This does not seem a good practice to me, let me quote from the documentation of the Gradle Java Plugin and give more details:

• test: Runs the unit tests using JUnit or TestNG.
• check Depends on: test
  Aggregate task that performs verification tasks, such as running the tests. Some plugins add their own verification tasks to check. You should also attach any custom Test tasks to this lifecycle task if you want them to execute for a full build. This task is added by the Base Plugin.
• assemble Depends on: jar, and all other tasks that create artifacts attached to the archives configuration
  Aggregate task that assembles all the archives in the project. This task is added by the Base Plugin.
• build Depends on: check, assemble
  Aggregate tasks that performs a full build of the project. This task is added by the Base Plugin.

See the task graph of the build task

Based on this, running -x test build has the following effects:

• assemble creates the necessary artifacts for the image
• test task is excluded, this means no unit tests
• check is not excluded, this means that every other type of tests and checks will be executed: functional tests, integration tests, performance tests, checkstyle, pmd, spotbugs, spotless, code coverage (e.g.: jacoco), etc
• build is not excluded, every other task that is hooked-up to build will be executed

I think this is not a good user experience and not a good example for the users. Since to me it seems having the right defaults is very important for paketo-buildpacks, I think based on the documentation, and based on the common practice, the right task to produce the necessary artifacts should be assemble so the default value of BP_GRADLE_BUILD_ARGUMENTS should be assemble --no-daemon.

[stigkj]

Examples of tasks that will run (unnecessarily) when using -x test build as the default:

• All linting type tasks like
  • Checkstyle
  • PMD
  • Findbugs
• All other test tasks
  • Component tests
  • Tests of other languages, like running npm run jest for javascript tests

[dmikusa]

Thanks for raising up this issue. +1 for making this change. It seems to bring the behavior more in line with the intent, which is to build the artifact and not run tests. I think it also puts this buildpack more in line with the Maven buildpack's behavior, which I also think is a good thing.

I should be able to get this fixed up shortly.