Fixed Simulation.exports setter

festim/generic_simulation.py

@@ -154,15 +154,15 @@ def exports(self):
     def exports(self, value):
         if value is None:
             self._exports = festim.Exports([])
+        elif isinstance(value, (festim.Export, festim.DerivedQuantities)):
+            self._exports = festim.Exports([value])
         elif isinstance(value, festim.Exports):
             self._exports = value
         elif isinstance(value, list):
             self._exports = festim.Exports(value)
-        elif isinstance(value, festim.Export):
-            self._exports = festim.Exports([value])
         else:
             raise TypeError(
-                "accepted types for exports are list, festim.Export or festim.Exports"
+                "accepted types for exports are list, festim.DerivedQuantities, festim.Export or festim.Exports"
             )
 
     @property

test/simulation/test_construction.py

@@ -62,6 +62,6 @@ def test_setting_exports_wrong_type(self, exp):
 
         with pytest.raises(
             TypeError,
-            match="accepted types for exports are list, festim.Export or festim.Exports",
+            match="accepted types for exports are list, festim.DerivedQuantities, festim.Export or festim.Exports",
         ):
             self.my_sim.exports = exp

test/simulation/test_postprocessing_integration.py

@@ -321,3 +321,27 @@ def test_surface_kinetics(self):
         data = derived_quantities.data
         assert np.isclose(data[1][1], 1)
         assert np.isclose(data[1][2], 2)
+
+
+def test_data_is_not_empty():
+    """
+    Test to catch bug #833
+    """
+
+    my_model = festim.Simulation()
+    my_model.mesh = festim.MeshFromVertices(vertices=np.linspace(0, 1, num=100))
+    my_model.materials = festim.Material(id=1, D_0=1, E_D=0)
+    my_model.T = festim.Temperature(value=700)
+    my_model.settings = festim.Settings(
+        absolute_tolerance=1e-10, relative_tolerance=1e-10, transient=False
+    )
+
+    flux_left = festim.SurfaceFlux(field=0, surface=1)
+    flux_right = festim.SurfaceFlux(field=0, surface=2)
+    my_model.exports = festim.DerivedQuantities([flux_left, flux_right])
+
+    my_model.initialise()
+    my_model.run()
+
+    assert flux_left.data != []
+    assert flux_right.data != []