Index: test/clang-tidy/check_clang_tidy.py
===================================================================
--- test/clang-tidy/check_clang_tidy.py
+++ test/clang-tidy/check_clang_tidy.py
@@ -73,9 +73,11 @@
 
   has_check_fixes = input_text.find('CHECK-FIXES') >= 0
   has_check_messages = input_text.find('CHECK-MESSAGES') >= 0
+  has_check_notes = input_text.find('CHECK-NOTES') >= 0
 
-  if not has_check_fixes and not has_check_messages:
-    sys.exit('Neither CHECK-FIXES nor CHECK-MESSAGES found in the input')
+  if not has_check_fixes and not has_check_messages and not has_check_notes:
+    sys.exit('Neither CHECK-FIXES nor CHECK-MESSAGES '
+             'nor CHECK-NOTES found in the input')
 
   # Remove the contents of the CHECK lines to avoid CHECKs matching on
   # themselves.  We need to keep the comments to preserve line numbers while
@@ -136,5 +138,18 @@
       print('FileCheck failed:\n' + e.output.decode())
       raise
 
+  if has_check_notes:
+    messages_file = temp_file_name + '.msg'
+    write_file(messages_file, clang_tidy_output)
+    try:
+      subprocess.check_output(
+          ['FileCheck', '-input-file=' + messages_file, input_file_name,
+           '-check-prefix=CHECK-NOTES',
+           '-implicit-check-not={{note|warning|error}}:'],
+          stderr=subprocess.STDOUT)
+    except subprocess.CalledProcessError as e:
+      print('FileCheck failed:\n' + e.output.decode())
+      raise
+
 if __name__ == '__main__':
   main()