Skip to content
  • Gregory Szorc's avatar
    run-tests: mechanism to report exceptions during test execution · bd8875b6473c
    Gregory Szorc authored
    Sometimes when running tests you introduce a ton of exceptions.
    The most extreme example of this is running Mercurial with Python 3,
    which currently spews thousands of exceptions when running the test
    harness.
    
    This commit adds an opt-in feature to run-tests.py to aggregate
    exceptions encountered by `hg` when running tests.
    
    When --exceptions is used, the test harness enables the
    "logexceptions" extension in the test environment. This extension
    wraps the Mercurial function to handle exceptions and writes
    information about the exception to a random filename in a directory
    defined by the test harness via an environment variable. At the
    end of the test harness, these files are parsed, aggregated, and
    a list of all unique Mercurial frames triggering exceptions is
    printed in order of frequency.
    
    This feature is intended to aid Python 3 development. I've only
    really tested it on Python 3. There is no shortage of improvements
    that could be made. e.g. we could write a separate file containing
    the exception report - maybe even an HTML report. We also don't
    capture which tests demonstrate the exceptions, so there's no turnkey
    way to test whether a code change made an exception disappear.
    Perfect is the enemy of good. I think the current patch is useful
    enough to land. Whoever uses it can send patches to imprve its
    usefulness.
    
    Differential Revision: https://phab.mercurial-scm.org/D1477
    bd8875b6473c