Clean up legacy vscode-test integration test infrastructure (pre task for new e2e framework)

Context

PR #647 deprecated npm run test by replacing it with a no-op that prints a deprecation notice. That was intentionally the smallest possible first step: it stops the dead legacy suite from running, but leaves all of the surrounding files and dependencies in place so the change is easy to revert.

This issue tracks the full removal of the legacy vscode-test based integration test infrastructure. It is a pre task for the new e2e testing framework planned for the 0.10.0 release. Doing the cleanup first gives the new framework a clean slate to land into.

Please read PR #647 first to understand the current state of package.json before starting on this work.

Goals

• Remove all code, config, and dependencies tied to the old vscode-test + Mocha integration suite.
• Leave Jest tests (npm run jesttest) completely untouched.
• Keep npm run test working but unblock it from being either repurposed or fully removed once the new e2e harness is ready.

Things to remove

1. Source / test files

• Delete the test/ directory and all its *.test.ts sources (the Mocha integration tests).
• Delete any out/test/ build artifacts (these are generated, but verify nothing references them).
• Search for stray references to removed test helpers (TestActionContext, TestOutputChannel, TestUserInput, runWithSetting, global.test.ts, etc.) and clean up imports.

2. Configuration

• Delete .vscode-test.js.
• Remove the Integration Tests launch configuration entry from .vscode/launch.json (if present).
• Remove any tasks.json entries that invoke vscode-test or build the test/ folder.
• Update tsconfig.json to drop test/ from include if it is listed there. Confirm npm run build still compiles without it.
• Update eslint.config.mjs to drop any test/ specific overrides (mocha plugin rules, etc.).
• Update extension.bundle.ts if it pulls anything from test/.

3. package.json cleanup

• Replace the temporary deprecation node -e one liner in the test script with either a full removal of the script or a forwarding alias (final decision belongs to whoever lands the new e2e framework).
• Remove the following devDependencies (verify with npm ls <pkg> that nothing else depends on them in this workspace):
  • @vscode/test-cli
  • @vscode/test-electron
  • @types/mocha
  • mocha
  • mocha-junit-reporter
  • mocha-multi-reporters
  • eslint-plugin-mocha
• Run npm install and commit the resulting package-lock.json update.

4. CI / pipelines

• Audit .github/workflows/*.yml and any Azure DevOps pipelines for steps that invoke npm run test, vscode-test, JUnit reporter outputs at test-results.xml, or download VS Code for headless test runs. Remove or update them.
• Confirm npm run jesttest still runs in CI and gates merges.

5. Documentation

• Search docs/, CONTRIBUTING.md, and the README for instructions that reference the old integration test workflow. Update or remove them.
• Add a short note in the contributing docs pointing readers at Jest (npm run jesttest) until the new e2e framework is in place.

Acceptance criteria

• npm run jesttest passes locally and in CI.
• npm run build, npm run lint, npm run prettier-fix, and npm run l10n all succeed.
• git grep -i vscode-test returns no remaining hits in source, configs, docs, or CI.
• node_modules/@vscode/test-cli and node_modules/@vscode/test-electron are no longer installed after a clean npm install.
• No references remain to Mocha or to the JUnit test-results.xml artifact.

Related

• PR #647 (deprecation, first step)
• Follow up: new e2e testing framework (separate issue / PR, 0.10.0)

Read PR #647 and inspect package.json first, then audit test/, .vscode-test.js, .vscode/launch.json, tasks.json, tsconfig.json, eslint.config.mjs, extension.bundle.ts, workflows, pipelines, and documentation for the listed references. Run npm ls for the dependencies before removing them and use git grep -i vscode-test to guide the cleanup. Done means the listed build, lint, formatting, localization, and Jest commands pass, with no legacy Mocha, vscode-test, or JUnit references remaining.