diff --git a/python/tests/test_Geom.py b/python/tests/test_Geom.py
index f988179fa..0f8c10066 100644
--- a/python/tests/test_Geom.py
+++ b/python/tests/test_Geom.py
@@ -72,7 +72,7 @@ class TestGeom:
         if update: modified.to_file(reference)
         assert geom_equal(modified,Geom.from_file(reference))
 
-    @pytest.mark.parametrize('stencil',[(1),(2),(3),(4)])
+    @pytest.mark.parametrize('stencil',[1,2,3,4])
     def test_clean(self,default,update,reference_dir,stencil):
         modified = copy.deepcopy(default)
         modified.clean(stencil)
@@ -82,12 +82,12 @@ class TestGeom:
         assert geom_equal(modified,Geom.from_file(reference))
 
     @pytest.mark.parametrize('grid',[
-                                     ((10,11,10)),
-                                     ([10,13,10]),
-                                     (np.array((10,10,10))),
-                                     (np.array((8, 10,12))),
-                                     (np.array((5, 4, 20))),
-                                     (np.array((10,20,2)) )
+                                     (10,11,10),
+                                     [10,13,10],
+                                     np.array((10,10,10)),
+                                     np.array((8, 10,12)),
+                                     np.array((5, 4, 20)),
+                                     np.array((10,20,2))
                                     ]
                             )
     def test_scale(self,default,update,reference_dir,grid):
@@ -98,7 +98,7 @@ class TestGeom:
         if update: modified.to_file(reference)
         assert geom_equal(modified,Geom.from_file(reference))
 
-    @pytest.mark.parametrize('periodic',[(True),(False)])
+    @pytest.mark.parametrize('periodic',[True,False])
     def test_tessellation_approaches(self,periodic):
         grid   = np.random.randint(10,20,3)
         size   = np.random.random(3) + 1.0
@@ -119,7 +119,7 @@ class TestGeom:
         Laguerre = Geom.from_Laguerre_tessellation(grid,size,seeds,weights,np.random.random()>0.5)
         assert np.all(Laguerre.microstructure == ms)
 
-    @pytest.mark.parametrize('approach',[('Laguerre'),('Voronoi')])
+    @pytest.mark.parametrize('approach',['Laguerre','Voronoi'])
     def test_tessellate_bicrystal(self,approach):
         grid  = np.random.randint(5,10,3)*2
         size  = grid.astype(np.float)
diff --git a/python/tests/test_VTK.py b/python/tests/test_VTK.py
index ef4090da5..627ea4007 100644
--- a/python/tests/test_VTK.py
+++ b/python/tests/test_VTK.py
@@ -1,5 +1,4 @@
 import os
-import sys
 
 import pytest
 import numpy as np