diff --git a/test/test_wiki_diff_matcher.py b/test/test_wiki_diff_matcher.py
index 364d3a1..33404e6 100644
--- a/test/test_wiki_diff_matcher.py
+++ b/test/test_wiki_diff_matcher.py
@@ -352,6 +352,10 @@ def test_actually_equal():
     assert_equal_enough(a, rev1)
     
 # slow test. comment out the following line to enable it.
+# Requires an uncompressed test/dumps/ikwiki.xml, which is not in the
+# repository; decompress the .bz2 in test/dumps first. Also writes debug
+# output to test_unicode_highlight_from/_to in the current directory on
+# every iteration.
 @pytest.mark.skip
 def test_diff_consistency():
     from mwxml import Dump
@@ -369,6 +373,9 @@ def test_diff_consistency():
             assert_equal_enough(b, rev)
             last_rev = rev
 
+# benchmark, not a pass/fail test; run it deliberately when tuning diff
+# performance. Requires an uncompressed test/dumps/ikwiki.xml, which is
+# not in the repository; decompress the .bz2 in test/dumps first.
 @pytest.mark.skip
 def test_benchmark_diff(benchmark):
     from mwxml import Dump