diff --git a/python/damask/_geom.py b/python/damask/_geom.py
index 26a7611c5..12dbcc181 100644
--- a/python/damask/_geom.py
+++ b/python/damask/_geom.py
@@ -612,12 +612,12 @@ class Geom:
     def canvas(self,grid=None,offset=None,fill=None):
         """Crop or enlarge/pad microstructure."""
         if fill is None: fill = np.nanmax(self.microstructure) + 1
+        if offset is None: offset = 0
         dtype = float if np.isnan(fill) or int(fill) != fill or self.microstructure.dtype==np.float else int
 
         canvas = np.full(self.grid if grid is None else grid,
                          fill if fill is not None else np.nanmax(self.microstructure)+1,
                          self.microstructure.dtype)
-        if offset is None: offset = 0
 
         l = np.clip( offset,          0,np.minimum(self.grid  +offset,grid))                        # noqa
         r = np.clip( offset+self.grid,0,np.minimum(self.grid*2+offset,grid))
diff --git a/python/tests/test_Geom.py b/python/tests/test_Geom.py
index e3aaf84a9..7a3823ab3 100644
--- a/python/tests/test_Geom.py
+++ b/python/tests/test_Geom.py
@@ -37,6 +37,7 @@ class TestGeom:
                         default.get_size(),
                         default.get_origin()
                        )
+        print(modified)
         assert geom_equal(modified,default)
 
 
@@ -58,6 +59,22 @@ class TestGeom:
         new = Geom.from_file(tmpdir.join('default.geom'))
         assert geom_equal(new,default)
 
+    def test_invalid_combination(self,default):
+        with pytest.raises(ValueError):
+            default.update(default.microstructure[1:,1:,1:],size=np.ones(3), rescale=True)
+
+    def test_invalid_size(self,default):
+        with pytest.raises(ValueError):
+            default.update(default.microstructure[1:,1:,1:],size=np.ones(2))
+
+    def test_invalid_microstructure(self,default):
+        with pytest.raises(ValueError):
+            default.update(default.microstructure[1])
+
+    def test_invalid_homogenization(self,default):
+        with pytest.raises(TypeError):
+            default.set_homogenization(homogenization=0)
+
     @pytest.mark.parametrize('directions,reflect',[
                                                    (['x'],        False),
                                                    (['x','y','z'],True),
@@ -122,7 +139,7 @@ class TestGeom:
 
     @pytest.mark.parametrize('axis_angle',[np.array([1,0,0,86.7]), np.array([0,1,0,90.4]), np.array([0,0,1,90]),
                                            np.array([1,0,0,175]),np.array([0,-1,0,178]),np.array([0,0,1,180])])
-    def test_rotate90(self,default,axis_angle):
+    def test_rotate360(self,default,axis_angle):
         modified = copy.deepcopy(default)
         for i in range(np.rint(360/axis_angle[3]).astype(int)):
             modified.rotate(Rotation.from_axis_angle(axis_angle,degrees=True))
@@ -138,6 +155,12 @@ class TestGeom:
         if update: modified.to_file(reference)
         assert geom_equal(modified,Geom.from_file(reference))
 
+    def test_canvas(self,default):
+        grid_add = np.random.randint(0,30,(3))
+        modified = copy.deepcopy(default)
+        modified.canvas(modified.grid + grid_add)
+        e = default.grid
+        assert np.all(modified.microstructure[:e[0],:e[1],:e[2]] == default.microstructure)
 
     @pytest.mark.parametrize('periodic',[True,False])
     def test_tessellation_approaches(self,periodic):