diff --git a/Tests/test_file_tiff.py b/Tests/test_file_tiff.py
index 157065ddd..16c43b00f 100644
--- a/Tests/test_file_tiff.py
+++ b/Tests/test_file_tiff.py
@@ -151,14 +151,14 @@ class TestFileTiff:
             assert im.info["dpi"] == (71.0, 71.0)
 
     @pytest.mark.parametrize(
-        "resolutionUnit, dpi",
+        "resolution_unit, dpi",
         [(None, 72.8), (2, 72.8), (3, 184.912)],
     )
-    def test_load_float_dpi(self, resolutionUnit, dpi):
+    def test_load_float_dpi(self, resolution_unit, dpi):
         with Image.open(
-            "Tests/images/hopper_float_dpi_" + str(resolutionUnit) + ".tif"
+            "Tests/images/hopper_float_dpi_" + str(resolution_unit) + ".tif"
         ) as im:
-            assert im.tag_v2.get(RESOLUTION_UNIT) == resolutionUnit
+            assert im.tag_v2.get(RESOLUTION_UNIT) == resolution_unit
             assert im.info["dpi"] == (dpi, dpi)
 
     def test_save_float_dpi(self, tmp_path):
diff --git a/Tests/test_imagemorph.py b/Tests/test_imagemorph.py
index 368c2bba1..7ec267bcd 100644
--- a/Tests/test_imagemorph.py
+++ b/Tests/test_imagemorph.py
@@ -48,12 +48,12 @@ def img_string_normalize(im):
     return img_to_string(string_to_img(im))
 
 
-def assert_img_equal(A, B):
-    assert img_to_string(A) == img_to_string(B)
+def assert_img_equal(a, b):
+    assert img_to_string(a) == img_to_string(b)
 
 
-def assert_img_equal_img_string(A, Bstring):
-    assert img_to_string(A) == img_string_normalize(Bstring)
+def assert_img_equal_img_string(a, b_string):
+    assert img_to_string(a) == img_string_normalize(b_string)
 
 
 def test_str_to_img():