CZ gate tests added

tests/test_lab_dev/test_transformations/test_cxgate.py

@@ -27,7 +27,7 @@
 
 class TestCXgate:
     r"""
-    Tests for the ``Pgate`` class.
+    Tests for the ``CXgate`` class.
     """
 
     def test_init(self):

tests/test_lab_dev/test_transformations/test_czgate.py

@@ -0,0 +1,55 @@
+# Copyright 2024 Xanadu Quantum Technologies Inc.
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Tests for the ``CZgate`` class."""
+
+# pylint: disable=missing-function-docstring, expression-not-assigned
+
+import re
+
+import pytest
+
+from mrmustard import math
+from mrmustard.lab_dev.states import Coherent, Vacuum
+from mrmustard.lab_dev.transformations import CZgate
+
+
+class TestCZgate:
+    r"""
+    Tests for the ``CZgate`` class.
+    """
+
+    def test_init(self):
+        "Tests the CZgate initialization."
+        cz = CZgate([0, 1], 0.3)
+        assert cz.modes == [0, 1]
+        assert cz.name == "CZgate"
+        assert cz.s.value == 0.3
+
+        with pytest.raises(
+            ValueError,
+            match=re.escape(
+                "The number of modes for a CZgate must be 2 (your input has 3 many modes)."
+            ),
+        ):
+            CZgate([0, 1, 2], 0.2)
+
+    @pytest.mark.parametrize("s", [0.1, 0.2, 1.5])
+    def test_application(self, s):
+        "Tests the application of CZgate"
+        psi = Coherent([0], 0, 1) >> Coherent([1], 1, 0) >> CZgate([0, 1], 1)
+        _, d, _ = psi.phase_space(s=0)
+        psi = Coherent([0], 0, 1) >> Coherent([1], 1, 0) >> CZgate([0, 1], 1)
+        d_by_hand = math.astensor([0, math.sqrt(complex(2)), (1 + s) * math.sqrt(complex(2)), 0])
+        assert math.allclose(d[0], d_by_hand)