Add first set of extension tests

.github/workflows/test-extension.yaml

@@ -0,0 +1,44 @@
+name: Test Extension
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  workflow_dispatch:
+
+jobs:
+  # Runs the suite against stock VS Code. A sibling job will run the same
+  # extension against Positron, which covers the language runtime, connection
+  # drivers and cell execution that stock VS Code cannot reach.
+  test-extension:
+    runs-on: ubuntu-latest
+    name: Test (VS Code)
+    defaults:
+      run:
+        working-directory: ggsql-vscode
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          cache: npm
+          cache-dependency-path: ggsql-vscode/package-lock.json
+
+      - name: Install XVFB
+        # The extension tests drive a real VS Code instance, which needs a
+        # display. The grammar tests do not, but run under the same command.
+        run: sudo apt-get -y update && sudo apt-get -y install xvfb
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Lint
+        run: npm run lint
+
+      - name: Run tests
+        run: xvfb-run -a npm test

.gitignore

@@ -113,3 +113,6 @@ ggsql.Rcheck/
 *.dmg
 *.AppImage
 .cargo-packager/
+
+# Superpowers SDD scratch (ledger, briefs, review packages)
+.superpowers/

ggsql-vscode/.gitignore

@@ -1 +1,3 @@
 out
+out-test
+.vscode-test/

ggsql-vscode/.vscode-test.mjs

@@ -0,0 +1,6 @@
+import { defineConfig } from '@vscode/test-cli';
+
+export default defineConfig({
+	files: 'out-test/test/**/*.test.js',
+	mocha: { timeout: 5000 },
+});

ggsql-vscode/.vscodeignore

@@ -4,6 +4,7 @@
 .yarnrc
 vsc-extension-quickstart.md
 **/tsconfig.json
+tsconfig.test.json
 **/.eslintrc.json
 **/*.map
 **/*.ts
@@ -15,3 +16,5 @@ esbuild.js
 out/**/*.map
 package-lock.json
 *.vsix
+out-test/**
+.vscode-test.mjs

ggsql-vscode/CLAUDE.md

@@ -22,7 +22,9 @@ ggsql-vscode/
 │   ├── codelens.ts           "▶ Run cell" lens above each cell
 │   ├── decorations.ts        Cell separator decorations
 │   ├── context.ts            Sets editor context keys (e.g. ggsql.hasCodeCells)
-│   └── types.ts              Shared interfaces
+│   ├── sqlAssociation.ts     One-time notice pointing at files.associations for .sql highlighting
+│   ├── types.ts              Shared interfaces
+│   └── test/                 Mocha suites (unit + activation) and the grammar fixture
 ├── syntaxes/
 │   └── ggsql.tmLanguage.json TextMate grammar (used for tokenization in VS Code)
 ├── examples/                 Sample .ggsql files
@@ -119,6 +121,33 @@ code --install-extension ggsql-<version>.vsix
 
 Watch mode for development: `npm run watch` (runs esbuild + tsc in parallel).
 
+## Testing
+
+```sh
+cd ggsql-vscode
+npm test              # grammar scopes, then the VS Code suites
+npm run test:grammar  # TextMate scopes only; no Electron, fast
+npm run test:extension
+```
+
+Tests live in `src/test/` and compile to `out-test/` via `tsconfig.test.json`, deliberately not to `out/`, which `esbuild.js` owns. The whole of `src/` compiles there, not just `src/test/`, because the unit tests import the extension's own modules. `@vscode/test-cli` launches a real VS Code instance, so a window appears while the suites run; CI wraps the same command in `xvfb-run`.
+
+Note that `tsc` does not prune output for deleted sources: if you delete or rename a test, remove its `.js` and `.js.map` from `out-test/test/` or the runner keeps executing the stale copy. `npm run test:extension` on its own does not recompile, so run `npm test` (or `npm run compile-tests` first) after editing any `.ts`.
+
+The suites cover the extension as stock VS Code sees it: activation, language resolution, cell parsing, `.sql` gating, CodeLens placement and TextMate scopes. The Positron surface (runtime manager, connection drivers, cell execution) is not covered, since it needs a Positron host. `sqlAssociation.ts`, `manager.ts` and `connections.ts` are also untested.
+
+Add new tests as `src/test/<name>.test.ts`; no config change is needed.
+
+### Editing the grammar fixture
+
+`src/test/grammar/highlight.gsql` uses `vscode-tmgrammar-test`'s annotation format, which has three rules worth knowing before you touch it:
+
+- The header must be exactly `-- SYNTAX TEST "source.ggsql"`. A trailing `>>`, which some examples show, makes the tool reject the file with a parse error rather than an assertion failure.
+- A `^` caret's column is the comment token length plus its index in the assertion line, matched against the source line's 0-based columns. Carets therefore cannot target source columns 0 and 1, which is why the `<---` form exists for line-initial tokens.
+- For `<---`, the dash count sets the assertion's right edge from column 0. It must be at least 1 and no more than the target token's length, so it is not cosmetic.
+
+Assertion lines are stripped before tokenization, so they never tokenize as ggsql comments.
+
 ## See also
 
 - [`/CLAUDE.md`](../CLAUDE.md) — workspace overview.