diff --git a/tests/filterpyflakes.py b/tests/filterpyflakes.py
--- a/tests/filterpyflakes.py
+++ b/tests/filterpyflakes.py
@@ -4,35 +4,48 @@
 
 import sys, re, os
 
-def makekey(message):
-    # "path/file:line: message"
-    match = re.search(r"(line \d+)", message)
-    line = ''
-    if match:
-        line = match.group(0)
-        message = re.sub(r"(line \d+)", '', message)
-    return re.sub(r"([^:]*):([^:]+):([^']*)('[^']*')(.*)$",
-                  r'\3:\5:\4:\1:\2:' + line,
-                  message)
+def makekey(typeandline):
+    """
+    for sorting lines by: msgtype, path/to/file, lineno, message
+
+    typeandline is a sequence of a message type and the entire message line
+    the message line format is path/to/file:line: message
+
+    >>> makekey((3, 'example.py:36: any message'))
+    (3, 'example.py', 36, ' any message')
+    >>> makekey((7, 'path/to/file.py:68: dummy message'))
+    (7, 'path/to/file.py', 68, ' dummy message')
+    >>> makekey((2, 'fn:88: m')) > makekey((2, 'fn:9: m'))
+    True
+    """
+
+    msgtype, line = typeandline
+    fname, line, message = line.split(":", 2)
+    # line as int for ordering 9 before 88
+    return msgtype, fname, int(line), message
+
 
 lines = []
 for line in sys.stdin:
-    # We whitelist tests
+    # We whitelist tests (see more messages in pyflakes.messages)
     pats = [
             r"imported but unused",
             r"local variable '.*' is assigned to but never used",
             r"unable to detect undefined names",
            ]
-    if not re.search('|'.join(pats), line):
-        continue
+    for msgtype, pat in enumerate(pats):
+        if re.search(pat, line):
+            break # pattern matches
+    else:
+        continue # no pattern matched, next line
     fn = line.split(':', 1)[0]
     f = open(os.path.join(os.path.dirname(os.path.dirname(__file__)), fn))
     data = f.read()
     f.close()
     if 'no-check-code' in data:
         continue
-    lines.append(line)
+    lines.append((msgtype, line))
 
-for line in sorted(lines, key = makekey):
+for msgtype, line in sorted(lines, key = makekey):
     sys.stdout.write(line)
 print