Add GitHub Actions CI and apply ruff fixes

The new workflow has three jobs that run on push and pull requests
against main: lint runs `ruff format --check` and `ruff check` over
src/ and tests/; test runs the full pytest suite on Python 3.11, 3.12,
and 3.13 with uv-managed interpreters; docker builds the production
image and smoke-tests `teslamate-mcp list-tools` inside it. Concurrency
group cancels superseded runs on the same ref.

Apply ruff's auto-fixes to db.py and conftest.py so the lint job passes
on a fresh checkout: combine nested async-with blocks, sort imports,
and drop a stale noqa.

Author: cobanov

.github/workflows/ci.yml

@@ -0,0 +1,65 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up uv
+        uses: astral-sh/setup-uv@v3
+        with:
+          enable-cache: true
+      - name: Install
+        run: uv sync --frozen
+      - name: Ruff format check
+        run: uv run ruff format --check src tests
+      - name: Ruff lint
+        run: uv run ruff check src tests
+
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.11", "3.12", "3.13"]
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up uv
+        uses: astral-sh/setup-uv@v3
+        with:
+          enable-cache: true
+      - name: Set up Python ${{ matrix.python-version }}
+        run: uv python install ${{ matrix.python-version }}
+      - name: Install
+        run: uv sync --frozen
+      - name: Run tests
+        run: uv run pytest -ra
+
+  docker:
+    runs-on: ubuntu-latest
+    needs: [lint, test]
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Build image
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: false
+          load: true
+          tags: teslamate-mcp:ci
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+      - name: Smoke test CLI inside image
+        run: docker run --rm teslamate-mcp:ci teslamate-mcp list-tools

src/teslamate_mcp/db.py

@@ -54,24 +54,19 @@ async def fetch_readonly(
 
     async with pool.connection() as conn:
         await conn.set_autocommit(False)
-        async with conn.transaction(force_rollback=True):
-            async with conn.cursor() as cur:
-                await cur.execute("SET TRANSACTION READ ONLY")
-                await cur.execute(
-                    sql.SQL("SET LOCAL statement_timeout = {ms}").format(
-                        ms=sql.Literal(stmt_ms)
-                    )
+        async with conn.transaction(force_rollback=True), conn.cursor() as cur:
+            await cur.execute("SET TRANSACTION READ ONLY")
+            await cur.execute(
+                sql.SQL("SET LOCAL statement_timeout = {ms}").format(ms=sql.Literal(stmt_ms))
+            )
+            await cur.execute(
+                sql.SQL("SET LOCAL lock_timeout = {ms}").format(ms=sql.Literal(lock_ms))
+            )
+            await cur.execute(
+                sql.SQL("SET LOCAL idle_in_transaction_session_timeout = {ms}").format(
+                    ms=sql.Literal(stmt_ms)
                 )
-                await cur.execute(
-                    sql.SQL("SET LOCAL lock_timeout = {ms}").format(
-                        ms=sql.Literal(lock_ms)
-                    )
-                )
-                await cur.execute(
-                    sql.SQL("SET LOCAL idle_in_transaction_session_timeout = {ms}").format(
-                        ms=sql.Literal(stmt_ms)
-                    )
-                )
-                await cur.execute(query)
-                rows = await cur.fetchall()
+            )
+            await cur.execute(query)
+            rows = await cur.fetchall()
     return rows_to_jsonable(rows)

tests/conftest.py

@@ -22,9 +22,8 @@
 except ImportError:  # pragma: no cover
     _HAS_TESTCONTAINERS = False
 
-from teslamate_mcp.db import build_pool
 from teslamate_mcp.config import Settings
-
+from teslamate_mcp.db import build_pool
 
 _SETUP_SQL = """
 DROP TABLE IF EXISTS demo_cars;
@@ -52,7 +51,7 @@ def postgres_container():
     try:
         container = PostgresContainer("postgres:16-alpine")
         container.start()
-    except Exception as exc:  # noqa: BLE001 — broad on purpose, any docker issue → skip
+    except Exception as exc:
         pytest.skip(f"Docker is not available: {exc}")
     try:
         yield container