distinguish 'file not found' and 'invalid file'

python/damask/_vtk.py

@@ -139,6 +139,8 @@ class VTK:
             vtkUnstructuredGrid, and vtkPolyData.
 
         """
+        if not os.path.isfile(fname):                                                               # vtk has a strange error handling
+            raise FileNotFoundError(f'No such file: {fname}')
         ext = Path(fname).suffix
         if ext == '.vtk' or dataset_type is not None:
             reader = vtk.vtkGenericDataObjectReader()
@@ -166,9 +168,6 @@ class VTK:
             else:
                 raise TypeError(f'Unknown file extension {ext}')
 
-            if not os.path.isfile(fname):
-                raise FileNotFoundError(f'No such file: {fname}')
-
             reader.SetFileName(str(fname))
             reader.Update()
             vtk_data = reader.GetOutput()

python/damask/mechanics.py

@@ -299,6 +299,9 @@ def _polar_decomposition(T,requested):
     if 'U' in requested:
         output.append(_np.einsum('...ji,...jk',R,T))
 
+    if len(output) == 0:
+        raise ValueError('Output needs to be out of V,R,U')
+
     return tuple(output)
 
 

python/tests/test_Geom.py

@@ -55,7 +55,7 @@ class TestGeom:
 
     def test_invalid_vtr(self,tmp_path):
         v = VTK.from_rectilinear_grid(np.random.randint(5,10,3)*2,np.random.random(3) + 1.0)
-        v.save(tmp_path/'no_materialpoint.vtr')
+        v.save(tmp_path/'no_materialpoint.vtr',parallel=False)
         with pytest.raises(ValueError):
             Geom.load(tmp_path/'no_materialpoint.vtr')
 

python/tests/test_VTK.py

@@ -100,12 +100,17 @@ class TestVTK:
         v = VTK.from_poly_data(points)
         v.save(tmp_path/fname)
 
-    @pytest.mark.parametrize('name,dataset_type',[('this_file_does_not_exist.vtk', None),
-                                                  ('this_file_does_not_exist.vtk','vtk'),
-                                                  ('this_file_does_not_exist.vtx', None)])
-    def test_invalid_dataset_type(self,name,dataset_type):
+    @pytest.mark.parametrize('fname,dataset_type',[('a_file.vtk', None),
+                                                   ('a_file.vtk','vtk'),
+                                                   ('a_file.vtx', None)])
+    def test_invalid_dataset_type(self,tmp_path,fname,dataset_type):
+        open(tmp_path/fname,'a').close()
         with pytest.raises(TypeError):
-            VTK.load(name,dataset_type)
+            VTK.load(tmp_path/fname,dataset_type)
+
+    def test_file_not_found(self):
+        with pytest.raises(FileNotFoundError):
+            VTK.load('/dev/null')
 
     def test_add_extension(self,tmp_path,default):
         default.save(tmp_path/'default.txt',parallel=False)