Added doc strings to testing classes

tests/devices/test_default_qutrit.py

@@ -1404,6 +1404,9 @@ def test_density_matrix_all_wires(self, qutrit_device_2_wires, wires, expected):
 @pytest.mark.jax
 @pytest.mark.parametrize("use_jit", [True, False])
 class TestQNodeIntegrationJax:
+    """Integration tests for default.qutrit with JAX. This test ensures it integrates
+        properly with the PennyLane UI, in particular the QNode."""
+
     def test_qutrit_circuit(self, tol, use_jit):
         """Test that the device provides the correct
         result for a simple circuit."""
@@ -1597,6 +1600,9 @@ def circuit(a, b):
 
 @pytest.mark.tf
 class TestQNodeIntegrationTF:
+    """Integration tests for default.qutrit with TensorFlow. This test ensures it integrates
+            properly with the PennyLane UI, in particular the QNode."""
+
     def test_qutrit_circuit(self, tol):
         """Test that the device provides the correct
         result for a simple circuit."""
@@ -1776,6 +1782,9 @@ def circuit(a, b):
 
 @pytest.mark.torch
 class TestQNodeIntegrationTorch:
+    """Integration tests for default.qutrit with Torch. This test ensures it integrates
+            properly with the PennyLane UI, in particular the QNode."""
+
     def test_qutrit_circuit(self, tol):
         """Test that the device provides the correct
         result for a simple circuit."""