tests/filterpyflakes.py

tests: add a test runner utility that prints nothing when all tests pass

This will be used to run tests through run-tests, which will expect no output
for a unit test that passes successfully.

The motivation for using unit tests instead of the current Python tests is that
they don't require an output file for comparison and that they're easier to write
because of the available tools from unittest (setup, asserts).

#!/usr/bin/env python

# Filter output by pyflakes to control which warnings we check

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)

lines = []
for line in sys.stdin:
    # We whitelist tests
    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
    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)

for line in sorted(lines, key = makekey):
    sys.stdout.write(line)
print