Expose the precision dtype to the caller so that users can specify the precision for testing

tests/test_cuquantum_cutensor_backend.py

@@ -23,7 +23,14 @@ def time(func):
 
 @pytest.mark.gpu
 @pytest.mark.parametrize("nqubits", [1, 2, 5, 10])
-def test_eval(nqubits: int):
+def test_eval(nqubits: int, dtype="complex128"):
+    """Evaluate QASM with cuQuantum.
+
+    Args:
+        nqubits (int): Total number of qubits in the system.
+        dtype (str): The data type for precision, 'complex64' for single,
+            'complex128' for double.
+    """
     import qibotn.cutn
 
     # Test qibo
@@ -33,8 +40,7 @@ def test_eval(nqubits: int):
         lambda: qibo_qft(nqubits, swaps=True))
 
     # Test Cuquantum
-    data_type = "complex128"
-    cutn_time, result_tn = time(lambda: qibotn.cutn.eval(qibo_circ, data_type))
+    cutn_time, result_tn = time(lambda: qibotn.cutn.eval(qibo_circ, dtype))
 
     assert 1e-2 * qibo_time < cutn_time < 1e2 * qibo_time
     assert np.allclose(