diff --git a/tests/test.fish b/tests/test.fish
index 7573b4001..2f2b8533b 100755
--- a/tests/test.fish
+++ b/tests/test.fish
@@ -61,14 +61,14 @@ for i in *.in
   else
 	set res fail
 	echo Output differs for file $i. Diff follows:
-	diff tmp.out $template_out
+	diff -u tmp.out $template_out
   end
 
   if diff tmp.err $template_err >/dev/null
   else
 	set res fail
 	echo Error output differs for file $i. Diff follows:
-	diff tmp.err $template_err
+	diff -u tmp.err $template_err
   end
 
   if test (cat tmp.status) = (cat $template_status)
diff --git a/tests/test6.in b/tests/test6.in
index 69f42d56c..93be594af 100755
--- a/tests/test6.in
+++ b/tests/test6.in
@@ -17,6 +17,12 @@ complete -C'BBBB -'
 # Test that erasing completions works correctly
 echo
 
+function sort
+    # GNU sort is really stupid, a non-C locale seems to make it assume --dictionary-order
+    # If I wanted --dictionary-order, I would have specified --dictionary-order!
+    env LC_ALL=C sort $argv
+end
+
 complete -c CCCC -l bar
 complete -c CCCC -l baz
 complete -c CCCC -o bar