--- a/proxy_cache_lock_ssi.t
+++ b/proxy_cache_lock_ssi.t
@@ -92,7 +92,7 @@ EOF
 
 # this doesn't result in an infinite timeout as second subrequest
 # is woken up by the postpone filter once first subrequest completes,
-# but this is suboptimal behavior
+# but this is suboptimal behaviour
 
 my $s = http_get('/locked', start => 1);
 like(http_get('/ssi.html'), qr/end/, 'cache lock ssi');

--- a/rewrite_unescape.t
+++ b/rewrite_unescape.t
@@ -72,7 +72,7 @@ mkdir($t->testdir() . '/directory');
 
 ###############################################################################
 
-# Some rewrites and expected (?) behavior
+# Some rewrites and expected (?) behaviour
 #
 # /t1?r=http%3A%2F%2Fexample.com%2F%3Ffrom
 # rewrite ^ $arg_r? redirect;
@@ -121,7 +121,7 @@ local $TODO = 'not yet';
 
 # Fixing this cases will require major changes to the whole approach and
 # likely to break some currently working cases.  On the other hand, current
-# behavior is far from acceptable.  Should be carefully thought.
+# behaviour is far from acceptable.  Should be carefully thought.
 
 location('/t1?r=http%3A%2F%2Fexample.com%2F%3Ffrom%3Dblah',
 	'http://example.com/?from=blah', 'escaped argument with complex query');