Improve test suite speed: pytest-xdist; qcut and qchem markers; update reconstruct tests

.github/workflows/tests.yml

@@ -45,7 +45,7 @@ jobs:
         run: |
           python -m pip install --upgrade pip
           pip install -r requirements-ci.txt
-          pip install wheel pytest pytest-cov pytest-mock flaky --upgrade
+          pip install wheel pytest pytest-cov pytest-mock pytest-xdist flaky --upgrade
 
       - name: Conditionally install openfermionpyscf
         if: contains(' 3.9', matrix.config.python-version)
@@ -65,9 +65,6 @@ jobs:
         if: contains(matrix.config.interfaces, 'jax')
         run: pip3 install jax jaxlib
 
-      - name: Install KaHyPar
-        run: pip3 install kahypar==1.1.7
-
       - name: Install PennyLane
         run: |
           pip install -r requirements-ci.txt
@@ -78,7 +75,7 @@ jobs:
         run: python -m pip install -i https://test.pypi.org/simple/ PennyLane-Lightning --pre --upgrade
 
       - name: Run tests
-        run: python -m pytest tests --cov=pennylane $COVERAGE_FLAGS
+        run: python -m pytest tests --cov=pennylane $COVERAGE_FLAGS -n auto
 
       - name: Adjust coverage file for Codecov
         run: bash <(sed -i 's/filename=\"/filename=\"pennylane\//g' coverage.xml)
@@ -88,6 +85,50 @@ jobs:
         with:
           file: ./coverage.xml
 
+  qcut-kahypar:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Cancel Previous Runs
+        uses: styfle/[email protected]
+        with:
+          access_token: ${{ github.token }}
+
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 2
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.8
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements-ci.txt
+          pip install wheel pytest pytest-cov pytest-mock pytest-xdist flaky --upgrade
+
+      - name: Install KaHyPar
+        run: pip3 install kahypar==1.1.7
+
+      - name: Install PennyLane
+        run: |
+          pip install -r requirements-ci.txt
+          python setup.py bdist_wheel
+          pip install dist/PennyLane*.whl
+
+      - name: Run tests
+        run: |
+          python -m pytest tests/ -m kahypar -n auto
+
+      - name: Adjust coverage file for Codecov
+        run: bash <(sed -i 's/filename=\"/filename=\"pennylane\//g' coverage.xml)
+
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v3
+        with:
+          file: ./coverage.xml
 
   device-tests:
     runs-on: ubuntu-latest
@@ -153,4 +194,4 @@ jobs:
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v3
         with:
-          file: ./coverage.xml
+          file: ./coverage.xml

tests/devices/test_default_gaussian.py

@@ -712,7 +712,9 @@ def test_sample_error_multi_wire(self, gaussian_device_2_wires):
         with pytest.raises(ValueError, match="Only one mode can be measured in homodyne"):
             sample = gaussian_device_2_wires.sample("P", [0, 1], [])
 
-    @pytest.mark.parametrize("observable", set(qml.ops.cv.obs) - set(["P", "X", "QuadOperator"]))
+    @pytest.mark.parametrize(
+        "observable", sorted(set(qml.ops.cv.obs) - set(["P", "X", "QuadOperator"]))
+    )
     def test_sample_error_unsupported_observable(self, gaussian_device_2_wires, observable):
         """Test that the sample function raises an error if the given observable is not supported"""
 

tests/fourier/test_reconstruct.py

@@ -59,7 +59,7 @@ def circuit(x):
     return circuit
 
 
-def fun_close(fun1, fun2, zero=None, tol=1e-5, samples=100):
+def fun_close(fun1, fun2, zero=None, tol=1e-5, samples=10):
     X = np.linspace(-np.pi, np.pi, samples)
     if zero is not None:
         X = qml.math.convert_like(X, zero)
@@ -730,7 +730,7 @@ def qnode_2(X, y):
 
 
 def qnode_3(X, Y):
-    for i in range(5):
+    for i in range(3):
         qml.RX(X[i], wires=0)
         qml.RY(Y[i], wires=0)
         qml.RX(X[i], wires=0)
@@ -941,7 +941,7 @@ def test_differentiability_jax(
                 grad = jax.grad(rec)
                 assert np.isclose(grad(x0), exp_qnode_grad(*params)[inner_key])
                 assert np.isclose(grad(x0 + 0.1), exp_grad(x0 + 0.1))
-                assert fun_close(grad, exp_grad, 10)
+                assert fun_close(grad, exp_grad, samples=3)
 
     @pytest.mark.parametrize(
         "qnode, params, ids, nums_frequency, spectra, shifts, exp_calls",

tests/pytest.ini

@@ -1,6 +1,7 @@
 [pytest]
 markers =
     slow: marks tests as slow (deselect with '-m "not slow"')
+    kahypar: marks tests from the QCut that use the KaHyPar package (deselect with '-m "not kahypar"')
     gpu: marks tests run on a GPU (deselect with '-m "not gpu"')
 filterwarnings = 
     ignore::DeprecationWarning:autograd.numpy.numpy_wrapper

tests/transforms/test_qcut.py

@@ -4188,6 +4188,7 @@ def make_weakly_connected_tape(
     return tape
 
 
+@pytest.mark.kahypar
 class TestKaHyPar:
     """Tests for the KaHyPar cutting function and utilities."""
 
@@ -4495,6 +4496,7 @@ def test_find_and_place_cuts(self, local_measurement, with_manual_cut, cut_strat
             )
 
 
+@pytest.mark.kahypar
 class TestAutoCutCircuit:
     """Integration tests for automatic-cutting-enabled `cut_circuit` transform.
     Mostly borrowing tests cases from ``TestCutCircuitTransform``.