add unittest test_variable_filter()

Author: syntron

tests/test_ModelicaSystemOMC.py

@@ -206,6 +206,53 @@ def _run_getSolutions(mod):
     assert np.isclose(x, x_analytical, rtol=1e-4).all()
 
 
+def test_variable_filter(model_firstorder):
+    mod = OMPython.ModelicaSystemOMC()
+    mod.model(
+        model_file=model_firstorder,
+        model_name="M",
+    )
+
+    a = -1
+    tau = -1 / a
+    stopTime = 5 * tau
+
+    simOptions = {"stopTime": stopTime, "stepSize": 0.1, "tolerance": 1e-8}
+    mod.setSimulationOptions(**simOptions)
+    mod.simulate()
+    sol_names1 = mod.getSolutions()
+    assert isinstance(sol_names1, tuple)
+    assert sol_names1 == ('a', 'der(x)', 'time', 'x')
+
+    mod.set_variable_filter(variable_filter='x')
+    mod.setSimulationOptions(stopTime=2.0)
+    mod.simulate()
+    sol_names2 = mod.getSolutions()
+    assert isinstance(sol_names2, tuple)
+    assert sol_names2 == ('a', 'time', 'x')
+
+    mod.set_variable_filter(variable_filter='der(x)')
+    mod.setSimulationOptions(stopTime=3.0)
+    mod.simulate()
+    sol_names3 = mod.getSolutions()
+    assert isinstance(sol_names3, tuple)
+    assert sol_names3 == ('a', 'time')
+
+    mod.set_variable_filter(variable_filter='der(x)', escape=True)
+    mod.setSimulationOptions(stopTime=3.0)
+    mod.simulate()
+    sol_names4 = mod.getSolutions()
+    assert isinstance(sol_names4, tuple)
+    assert sol_names4 == ('a', 'der(x)', 'time')
+
+    mod.set_variable_filter(variable_filter='a')
+    mod.setSimulationOptions(stopTime=2.0)
+    mod.simulate()
+    sol_names5 = mod.getSolutions()
+    assert isinstance(sol_names5, tuple)
+    assert sol_names5 == ('a', 'time')
+
+
 def test_getters(tmp_path):
     model_file = tmp_path / "M_getters.mo"
     model_file.write_text("""