diff --git a/tests/test_image.py b/tests/test_image.py
index 3e3fc869949cd950d57060a6abc02ec00db0844d..43950051daa3e7d13032c09d747b0ec600bf595a 100644
--- a/tests/test_image.py
+++ b/tests/test_image.py
@@ -388,10 +388,10 @@ def test_addExt():
         ('compressed.nii.gz',              True,  'compressed.nii.gz'),
         ('uncompressed',                   True,  'uncompressed.nii'),
         ('uncompressed.nii',               True,  'uncompressed.nii'),
-        ('img_hdr_pair',                   True,  'img_hdr_pair.img'),
+        ('img_hdr_pair',                   True,  'img_hdr_pair.hdr'),
         ('img_hdr_pair.hdr',               True,  'img_hdr_pair.hdr'),
         ('img_hdr_pair.img',               True,  'img_hdr_pair.img'),
-        ('compressed_img_hdr_pair',        True,  'compressed_img_hdr_pair.img.gz'),
+        ('compressed_img_hdr_pair',        True,  'compressed_img_hdr_pair.hdr.gz'),
         ('compressed_img_hdr_pair.img.gz', True,  'compressed_img_hdr_pair.img.gz'),
         ('compressed_img_hdr_pair.hdr.gz', True,  'compressed_img_hdr_pair.hdr.gz'),
         ('ambiguous.nii',                  True,  'ambiguous.nii'),