javascript: Test goal with package manager installed test runner supp…

…ort (#18554)

Add support for running package manager installed test runners, and
`javascript_test` targets.

There's multiple flavors of how coverage reports are configured (extra
args, separate script) depending on test runner.
To stay unopinionated I implemented support for both. If one has to go,
extra args is the one.

This PR includes:
1. Introduce a new `scripts` mapper build symbol `node_test_script`,
where users can augment default behaviour, which is:
2. To run `(npm|pnpm|yarn) run test`, the "standard" way to execute test
runners.
3. Coverage reports per test support. I made no effort to merge the
coverage reports.
4. No batch support (yet). I think it would be good to OOTB assume that
`npm run test <all-files-for-workspace>` is preferred to current
behaviour of 1 run per file. See e.g
https://jestjs.io/docs/cli#--maxworkersnumstring.

Fixes #18524.

src/python/pants/backend/experimental/javascript/register.py

@@ -6,11 +6,16 @@
 from typing import Iterable
 
 from pants.backend.javascript import package_json
-from pants.backend.javascript.goals import lockfile, tailor
+from pants.backend.javascript.goals import lockfile, tailor, test
 from pants.backend.javascript.package.rules import rules as package_rules
 from pants.backend.javascript.run.rules import rules as run_rules
 from pants.backend.javascript.subsystems import nodejs
-from pants.backend.javascript.target_types import JSSourcesGeneratorTarget, JSSourceTarget
+from pants.backend.javascript.target_types import (
+    JSSourcesGeneratorTarget,
+    JSSourceTarget,
+    JSTestsGeneratorTarget,
+    JSTestTarget,
+)
 from pants.build_graph.build_file_aliases import BuildFileAliases
 from pants.engine.rules import Rule
 from pants.engine.target import Target
@@ -24,13 +29,16 @@ def rules() -> Iterable[Rule | UnionRule]:
         *lockfile.rules(),
         *package_rules(),
         *run_rules(),
+        *test.rules(),
     )
 
 
 def target_types() -> Iterable[type[Target]]:
     return (
         JSSourceTarget,
         JSSourcesGeneratorTarget,
+        JSTestTarget,
+        JSTestsGeneratorTarget,
         *package_json.target_types(),
     )
 

src/python/pants/backend/javascript/goals/BUILD

@@ -5,4 +5,8 @@ python_sources()
 
 python_tests(
     name="tests",
+    # The package.json files are inlined in ./test_integration_tests.py
+    overrides={
+        "test_integration_test.py": dict(dependencies=["./jest_resources", "./mocha_resources"]),
+    },
 )

src/python/pants/backend/javascript/goals/jest_resources/BUILD

@@ -0,0 +1,4 @@
+# Copyright 2023 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+resources(sources=["package-lock.json"])