--- a/candolint/handlers.py	Mon Sep 18 18:52:34 2017 +0800
+++ b/candolint/handlers.py	Tue Sep 19 22:29:13 2017 +0800
@@ -145,13 +145,9 @@
             self.write(line['text'])
             self.write('\n')
 
-    def get_html(self, project, check, lines):
-        adapter = project.get_adapter()
-        for line in lines:
-            if 'filename' in line:
-                line['link'] = adapter.get_line_url(check.change, line)
+    def get_reference_check(self, check):
         if check.success:
-            reference = (Check
+            return (Check
                 .select(*Check.get_light_fields())
                 .join(Change)
                 .where(Check.project == check.project)
@@ -161,8 +157,14 @@
                 .where(Check.ordinal < check.ordinal)
                 .order_by(Check.ordinal.desc())
                 .first())
-        else:
-            reference = None
+        return None
+
+    def get_html(self, project, check, lines):
+        adapter = project.get_adapter()
+        for line in lines:
+            if 'filename' in line:
+                line['link'] = adapter.get_line_url(check.change, line)
+        reference = self.get_reference_check(check)
         self.render('check.html', project=project, check=check, lines=lines, adapter=adapter, reference=reference)