Refactors the MatlabWrapper to load Matlab in the background (#41)

Author: StephenNneji

.github/workflows/run_tests.yml

@@ -49,4 +49,4 @@ jobs:
       - name: Install and Test with pytest
         run: |
           python -m pip install -e .[Dev]
-          pytest tests/ --cov=${{ github.event.repository.name }} --cov-report=html:htmlcov --cov-report=term
+          pytest tests/ --cov=RATpy --cov-report=term

RATpy/wrappers.py

@@ -1,4 +1,5 @@
 import pathlib
+from contextlib import suppress
 from typing import Callable, Tuple
 
 import numpy as np
@@ -7,6 +8,24 @@
 import RATpy.rat_core
 
 
+def start_matlab():
+    """Starts MATLAB asynchronously and returns a future to retrieve the engine later
+
+    Returns
+    -------
+    future : matlab.engine.futureresult.FutureResult
+        A future used to get the actual matlab engine
+
+    """
+    future = None
+    with suppress(ImportError):
+        import matlab.engine
+
+        future = matlab.engine.start_matlab(background=True)
+
+    return future
+
+
 class MatlabWrapper:
     """Creates a python callback for a MATLAB function.
 
@@ -17,21 +36,17 @@ class MatlabWrapper:
 
     """
 
+    loader = start_matlab()
+
     def __init__(self, filename: str) -> None:
-        self.engine = None
-        try:
-            import matlab.engine
-        except ImportError:
+        if self.loader is None:
             raise ImportError("matlabengine is required to use MatlabWrapper") from None
-        self.engine = matlab.engine.start_matlab()
+
+        self.engine = self.loader.result()
         path = pathlib.Path(filename)
         self.engine.cd(str(path.parent), nargout=0)
         self.function_name = path.stem
 
-    def __del__(self):
-        if self.engine is not None:
-            self.engine.quit()
-
     def getHandle(self) -> Callable[[ArrayLike, ArrayLike, ArrayLike, int, int], Tuple[ArrayLike, float]]:
         """Returns a wrapper for the custom MATLAB function
 

requirements-dev.txt

@@ -6,3 +6,4 @@ pytest >= 7.4.0
 pytest-cov >= 4.1.0
 matplotlib >= 3.8.3
 StrEnum >= 0.4.15; python_version < '3.11'
+ruff >= 0.4.10

requirements.txt

@@ -618,13 +618,14 @@ def test_make_input(test_project, test_problem, test_cells, test_limits, test_pr
         "domainRatio",
     ]
 
-    mocked_matlab_module = mock.MagicMock()
+    mocked_matlab_future = mock.MagicMock()
     mocked_engine = mock.MagicMock()
-    mocked_matlab_module.engine.start_matlab.return_value = mocked_engine
+    mocked_matlab_future.result.return_value = mocked_engine
 
-    with mock.patch.dict(
-        "sys.modules",
-        {"matlab": mocked_matlab_module, "matlab.engine": mocked_matlab_module.engine},
+    with mock.patch.object(
+        RATpy.wrappers.MatlabWrapper,
+        "loader",
+        mocked_matlab_future,
     ), mock.patch.object(RATpy.rat_core, "DylibEngine", mock.MagicMock()), mock.patch.object(
         RATpy.inputs,
         "get_python_handle",
@@ -757,13 +758,13 @@ def test_make_cells(test_project, test_cells, request) -> None:
     test_project = request.getfixturevalue(test_project)
     test_cells = request.getfixturevalue(test_cells)
 
-    mocked_matlab_module = mock.MagicMock()
-    mocked_matlab_engine = mock.MagicMock()
-    mocked_matlab_module.engine.start_matlab.return_value = mocked_matlab_engine
-
-    with mock.patch.dict(
-        "sys.modules",
-        {"matlab": mocked_matlab_module, "matlab.engine": mocked_matlab_module.engine},
+    mocked_matlab_future = mock.MagicMock()
+    mocked_engine = mock.MagicMock()
+    mocked_matlab_future.result.return_value = mocked_engine
+    with mock.patch.object(
+        RATpy.wrappers.MatlabWrapper,
+        "loader",
+        mocked_matlab_future,
     ), mock.patch.object(RATpy.rat_core, "DylibEngine", mock.MagicMock()), mock.patch.object(
         RATpy.inputs,
         "get_python_handle",

tests/test_inputs.py

@@ -7,15 +7,16 @@
 
 
 def test_matlab_wrapper() -> None:
-    with mock.patch.dict("sys.modules", {"matlab": mock.MagicMock(side_effect=ImportError)}), pytest.raises(
-        ImportError,
+    with (
+        mock.patch.object(RATpy.wrappers.MatlabWrapper, "loader", None),
+        pytest.raises(ImportError),
     ):
         RATpy.wrappers.MatlabWrapper("demo.m")
-    mocked_matlab_module = mock.MagicMock()
-    mocked_engine = mock.MagicMock()
-    mocked_matlab_module.engine.start_matlab.return_value = mocked_engine
 
-    with mock.patch.dict("sys.modules", {"matlab": mocked_matlab_module, "matlab.engine": mocked_matlab_module.engine}):
+    mocked_matlab_future = mock.MagicMock()
+    mocked_engine = mock.MagicMock()
+    mocked_matlab_future.result.return_value = mocked_engine
+    with mock.patch.object(RATpy.wrappers.MatlabWrapper, "loader", mocked_matlab_future):
         wrapper = RATpy.wrappers.MatlabWrapper("demo.m")
         assert wrapper.function_name == "demo"
         mocked_engine.cd.assert_called_once()