tests/silenttestrunner.py

test-pathencode: randomize length of each path component

This makes it possible for long and short components to exist in the same path.
This also makes shorter path components more likely. For
randint(1, randint(1, n)), the likelihood that one sees a number k
(1 <= k <= n) is 1/n * (\sum_{k=i}^n 1/i). This decreases with k, much like in
the real world where shorter paths are more common than longer ones.

The previous fix and this one together cause issue3958 to be detected by this
test with reasonable frequency. When this test was run 100 times in a loop, the
issue was detected 30 of those times.

import unittest, sys

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)