Add mechanism for launcher to detect engine capabilities

[jlink]

Use cases:

• Launcher gives warning if a Specification (e.g. AllTestsSpecification) is not supported, so that user knows that their tests might not be picked up as expected.
• IDE/Launcher switches on features (e.g. Tagging) only if all/some registered engines support it.
• Launcher/IDE won't use features that break backwards compatibility

Potential capabilities to announce:

• Supported specifications
• Tagging
• Engine filters
• Support for opentest4j
• Custom events
• Supported API version (starting with 5.0)?

This feature needs both:

• A way for engines to declare their capabilities
• A way for users of launcher to find out about capabilities

[marcphilipp]

Another potential capability: Parallelization

[saint88]

Hello
When you plan to add a parallel launch of tests in Junit 5 via the plugin maven surefire.

[saint88]

It's critical options for migrate our peroject from junit 4.12 to Jupiter

[sormuras]

Jupiter will soon support parallel execution: see #60 and the related feature branch https://github.com/junit-team/junit5/tree/experiments/parallel-execution

[saint88]

Ok. Thanks. I will be wait. =)

[jlink]

Haven’t checked the implementation but I wonder if that could/should be a platform feature?

…

Am 04.04.2018 um 15:12 schrieb Christian Stein ***@***.***>: Jupiter will soon support parallel execution: see #60 and the related feature branch https://github.com/junit-team/junit5/tree/experiments/parallel-execution — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

[sormuras]

Maybe. At the moment, it's just an opt-in feature of the Jupiter engine.

Wanted to direct @saint88 to #60 to keep this issue free from Jupiter-related requests.

[marcphilipp]

@jlink I'm working on #60 with @leonard84 since Spock also wants to add support for parallel execution. Engines that extend HierarchicalTestEngine will be able to use it so it is kind of a Platform feature. However, we believe it should be possible to enable/disable parallel execution per engine.

[aaronq]

@marcphilipp do you know when your parallel changes will get released?

[marcphilipp]

@aaronq The plan is to polish them and publish them as experimental in 5.3 M1... so 1-2 months.

[sormuras]

Bump/touch.

Especially the "warning part" is crucial when debugging a "No tests found" error message after a test run that should have found tests. For example: engines are present, select source test sources, filters are okay, ... but no engine supports the selected selectors.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. Given the limited bandwidth of the team, it will be automatically closed if no further activity occurs. Thank you for your contribution.

[leonard84]

This feature would have helped with spockframework/spock#1288

[stale]

This issue has been automatically marked as stale because it has not had recent activity. Given the limited bandwidth of the team, it will be automatically closed if no further activity occurs. Thank you for your contribution.

[leonard84]

I'd say it is still relevant