tests/silenttestrunner.py

dirs.addpath: rework algorithm to search forward

This improves performance because it uses strchr rather than a loop.

For LLVM/clang version "Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM
3.5svn)" on OS X, for a repo with over 200,000 files, this improves perfdirs
from 0.248 seconds to 0.230 (7.3%)

For gcc 4.4.6 on Linux, for a test repo with over 500,000 files, this improves
perfdirs from 0.704 seconds to 0.658 (6.5%).

import unittest, sys, os

def main(modulename):
    '''run the tests found in module, printing nothing when all tests pass'''
    module = sys.modules[modulename]
    suite = unittest.defaultTestLoader.loadTestsFromModule(module)
    results = unittest.TestResult()
    suite.run(results)
    if results.errors or results.failures:
        for tc, exc in results.errors:
            print 'ERROR:', tc
            print
            sys.stdout.write(exc)
        for tc, exc in results.failures:
            print 'FAIL:', tc
            print
            sys.stdout.write(exc)
        sys.exit(1)

if os.environ.get('SILENT_BE_NOISY'):
    main = unittest.main