scala-cli-integration-tests

# Integration tests (Scala CLI) **Location**: `modules/integration/`. Tests invoke the CLI as an external process. **Run**: `./mill -i integration.test.jvm` (all). Filter: `./mill -i integration.test.jvm 'scala.cli.integration.RunTestsDefault.*'` or by test name. Native: `./mill -i integration.test.native`. **Always set `CI=true` when running integration tests**, unless the user explicitly asks otherwise: ```bash CI=true ./mill -i integration.test.jvm 'scala.cli.integration.RunTestsDefault.*' ``` This disables test parallelism, so the run mirrors how the tests behave on CI. It is slower, but the extra time is an acceptable trade-off for reproducible results. **Structure**: `*TestDefinitions.scala` (abstract, holds test logic) → `*TestsDefault`, `*Tests213`, etc. (concrete, Scala version trait). Traits: `TestDefault`, `Test212`, `Test213`, `Test3Lts`, `Test3NextRc`. **Adding a test**: 1. Open the right `*TestDefinitions` (e.g. `RunTestDefinitions` for `run`). 2. Add `test("description") { … }` using `TestInputs(os.rel / "Main.scala" -> "…").fromRoot { root => … }` and `os.proc(TestUtil.cli, "run", …).call(cwd = root)`. 3. Assert on stdout/stderr. **Helpers**: `TestInputs(...).fromRoot`, `TestUtil.cli`. Test groups (CI): `SCALA_CLI_IT_GROUP=1..5`; see `modules/integration/` for group mapping.