ci: add ubuntu-latest test pipelines (#19)

* ci: add ubuntu-latest test pipelines for highest/lowest torch

Add 4 GitHub-hosted Linux pipelines that run on ubuntu-latest:
- highest-torch slow, highest-torch fast
- lowest-torch slow, lowest-torch fast

Each runs the corresponding make target with --junit and uploads its
test-results artifact. Ungated and independent of the macOS self-hosted
jobs so they also run on forks.

* ci: gate test matrix behind a tiered check/smoke/tutorials stage

Introduce a tiered CI structure:
- Tier 1 (ubuntu-latest, ungated): make check, make test-smoke,
  make test-tutorials.
- Tier 2 (needs all of Tier 1): the 4 linux test pipelines and the
  macOS test run.

Move `check` off the macOS self-hosted runner to ubuntu-latest and drop
its repo gate so the gate also runs on forks (otherwise Tier 2 would be
skipped there). test-smoke/test-tutorials targets are added by a
separate change; until then those jobs fail and Tier 2 is skipped.

* ci: set linux test pipeline timeout-minutes to 120

* build: gate pre-commit hook install behind INSTALL_PRECOMMIT

Port the scripts/make changes from coreai-opt#497 so INSTALL_PRECOMMIT
is a real knob: setup_env.sh defaults it (false in --ensure mode, true
otherwise) and threads it to install_pre_commit_hooks.sh, which skips
`pre-commit install -f` when INSTALL_PRECOMMIT=false.

* ci: set INSTALL_PRECOMMIT=false for the test, smoke, and tutorial jobs

Skip git-hook configuration during env setup for the 4 linux test jobs,
the macOS test run, test-smoke, and test-tutorials. `check` is left as-is.

* ci: collapse linux test jobs into a strategy matrix

GitHub Actions doesn't support YAML anchors, so collapse the 4 linux-*
test jobs into a single `linux-tests` job with a strategy.matrix over
{highest,lowest} x {slow,fast}, declaring needs:/env:/steps once. Also
drop the redundant "Stage 2 runs only if..." comment.

* test: set strict=False on the resnet export xfail

Author: guru-desh

.github/workflows/ci.yaml

@@ -20,10 +20,10 @@ concurrency:
 
 jobs:
 
+  # ── Stage 1: cheap correctness gate (ubuntu-latest, ungated). ──
   check:
-    name: macOS / make check
-    if: github.repository == 'apple/coreai-optimization'
-    runs-on: [self-hosted, macos, tahoe, ARM64]
+    name: Linux / make check
+    runs-on: ubuntu-latest
     timeout-minutes: 30
     steps:
       - name: Check out repository
@@ -37,12 +37,47 @@ jobs:
       - name: Run `make check`
         run: make check
 
+  test-smoke:
+    name: Linux / make test-smoke
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    env:
+      INSTALL_PRECOMMIT: "false"
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+      - name: Install uv
+        uses: astral-sh/setup-uv@fac544c07dec837d0ccb6301d7b5580bf5edae39 # v8.2.0
+        with:
+          enable-cache: false
+      - name: Run `make test-smoke`
+        run: make test-smoke
+
+  test-tutorials:
+    name: Linux / make test-tutorials
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    env:
+      INSTALL_PRECOMMIT: "false"
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+      - name: Install uv
+        uses: astral-sh/setup-uv@fac544c07dec837d0ccb6301d7b5580bf5edae39 # v8.2.0
+        with:
+          enable-cache: false
+      - name: Run `make test-tutorials`
+        run: make test-tutorials
+
+  # ── Stage 2: full test matrix, gated on Stage 1. ──
   macos-tests:
     name: macOS / make test-highest-pytorch / markers=not-slow
-    needs: [check]
+    needs: [check, test-smoke, test-tutorials]
     if: github.repository == 'apple/coreai-optimization'
     runs-on: [self-hosted, macos, tahoe, ARM64]
     timeout-minutes: 60
+    env:
+      INSTALL_PRECOMMIT: "false"
     steps:
       - name: Check out repository
         uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
@@ -58,3 +93,31 @@ jobs:
         with:
           name: test-results-macos-highest-fast
           path: test-results/
+
+  linux-tests:
+    name: Linux / make test-${{ matrix.torch }}-pytorch / markers=${{ matrix.speed == 'slow' && 'slow' || 'not-slow' }}
+    needs: [check, test-smoke, test-tutorials]
+    runs-on: ubuntu-latest
+    timeout-minutes: 120
+    env:
+      INSTALL_PRECOMMIT: "false"
+    strategy:
+      fail-fast: false
+      matrix:
+        torch: [highest, lowest]
+        speed: [slow, fast]
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+      - name: Install uv
+        uses: astral-sh/setup-uv@fac544c07dec837d0ccb6301d7b5580bf5edae39 # v8.2.0
+        with:
+          enable-cache: false
+      - name: Run `make test-${{ matrix.torch }}-pytorch`
+        run: make test-${{ matrix.torch }}-pytorch PYTEST_ARGS="--marker '${{ matrix.speed == 'slow' && 'slow' || 'not slow' }}' --junit"
+      - name: Upload test results
+        if: always()
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: test-results-linux-${{ matrix.torch }}-${{ matrix.speed }}
+          path: test-results/

scripts/make/install_pre_commit_hooks.sh

@@ -60,5 +60,9 @@ if ! command -v lychee &>/dev/null; then
 fi
 
 # Configure git hooks. Force-install so the shebang points to the current venv.
-uv run --no-sync --active pre-commit install -f
-echo "✓ Pre-commit hooks configured to use $VIRTUAL_ENV"
+if [[ "${INSTALL_PRECOMMIT:-true}" == "false" ]]; then
+    echo "Skipping git hook configuration (INSTALL_PRECOMMIT=$INSTALL_PRECOMMIT)"
+else
+    uv run --no-sync --active pre-commit install -f
+    echo "✓ Pre-commit hooks configured to use $VIRTUAL_ENV"
+fi

scripts/make/setup_env.sh

@@ -195,6 +195,12 @@ while [[ $# -gt 0 ]]; do
     esac
 done
 
+if [[ "$ENSURE_MODE" == true ]]; then
+    INSTALL_PRECOMMIT="${INSTALL_PRECOMMIT:-false}"
+else
+    INSTALL_PRECOMMIT="${INSTALL_PRECOMMIT:-true}"
+fi
+
 # Validate required arguments
 if [[ -z "$PYTHON_VERSION" ]]; then
     echo "Error: --python-version is required"
@@ -339,11 +345,11 @@ echo "Running: ${SYNC_CMD[*]}"
 "${SYNC_CMD[@]}"
 
 echo ""
-echo "[3/3] Configuring pre-commit hooks..."
+echo "[3/3] Installing hook dependencies and configuring pre-commit hooks..."
 if [[ "$VENV_PREEXISTED" == "true" ]]; then
     echo "Skipped (venv already exists, hooks already configured)"
 else
-    "$SCRIPTS_DIR/make/install_pre_commit_hooks.sh" "$COREAI_OPT_HOME"
+    INSTALL_PRECOMMIT="$INSTALL_PRECOMMIT" "$SCRIPTS_DIR/make/install_pre_commit_hooks.sh" "$COREAI_OPT_HOME"
 fi
 
 echo ""

tests/export/test_graph_mode_mlir_export.py

@@ -211,6 +211,7 @@ def test_mnist_export(
         "[Export Tests] ResNet50 graph-mode int8 quantization"
         " SNR falls below threshold on Linux (19.44 < 20.0)"
     ),
+    strict=False,
 )
 def test_resnet_export(
     resnet50_model: torch.nn.Module,