revert mock backends to numpy

qutip/tests/core/test_numpy_backend.py

@@ -1,4 +1,5 @@
 import pytest
+import numpy as np
 from unittest.mock import patch, MagicMock
 
 from ...settings import settings
@@ -17,18 +18,21 @@ def test_backend_property(self):
 
         settings.core["numpy_backend"] = mock_jax
         assert np_backend.backend is mock_jax
+        settings.core["numpy_backend"] = np
 
     def test_getattr_numpy(self):
         settings.core["numpy_backend"] = mock_np
         np_backend = NumpyBackend()
         mock_np.sum = MagicMock(return_value="numpy_sum")
         assert np_backend.sum([1, 2, 3]) == "numpy_sum"
+        settings.core["numpy_backend"] = np
 
     def test_getattr_jax(self):
         settings.core["numpy_backend"] = mock_jax
         np_backend = NumpyBackend()
         mock_jax.sum = MagicMock(return_value="jax_sum")
         assert np_backend.sum([1, 2, 3]) == "jax_sum"
+        settings.core["numpy_backend"] = np
 
     @pytest.mark.parametrize("backend", [mock_np, mock_jax])
     def test_backend_functionality(self, backend):
@@ -39,9 +43,5 @@ def test_backend_functionality(self, backend):
         result = np_backend.sum([1, 2, 3])
         assert result == "sum_result"
         backend.sum.assert_called_with([1, 2, 3])
+        settings.core["numpy_backend"] = np
 
-
-@pytest.fixture(scope='module')
-def mock_settings():
-    with patch.dict(settings.core, {"numpy_backend": mock_np}):
-        yield settings