annotate tests/hypothesishelpers.py @ 40093:726cfc47f17a

contrib: add an utility module to parse test scripts

This patch centralizes the logic to pick up code fragments embedded in
*.t script, in order to:

  - apply checking with patterns in check-code.py on such embedded
    code fragments

    Now, check-code.py completely ignores embedded code
    fragments. I'll post another patch series to check them.

  - replace similar code path in contrib/import-checker.py

    Current import-checker.py has problems below. Fixing each of them
    is a little difficult, because parsing logic and pattern strings
    are tightly coupled.

    - overlook (or mis-detect) the end of inline script in doctest
      style

      8a8dd6e4a97a fixed a part of this issue, but not enough.

    - it overlooks inline script in doctest style at the end of file
      (and ignores invalid un-closed heredoc at the end of file, too)

    - it overlooks code fragment in styles below
      - "python <<EOF" (heredoc should be "cat > file <<EOF" style)
      - "cat > foobar.py << ANYLIMIT" (limit mark should be "EOF")
      - "cat << EOF > foobar.py" (filename should be placed before limit mark)
      - "cat >> foobar.py << EOF" (appending is ignored)

    - it is not extensible for other than python code fragments
      (e.g. shell script, hgrc file, and so on)

This new module can detect python code fragments in styles below:

  - inline script in doctest style (starting by "  >>> " line)
  - python invocation with heredoc script ("python <<EOF")
  - python script in heredoc style (redirected into ".py" file)

As an example of extensibility of new module, this patch also contains
implementation to pick up code fragment below. This will be useful to
add additional restriction for them, for example.

  - shell script in heredoc style (redirected into ".sh" file)
  - hgrc configuration in heredoc style (redirected into hgrc or $HGRCPATH)

# Helper module to use the Hypothesis tool in tests
#
# Copyright 2015 David R. MacIver
#
# For details see http://hypothesis.readthedocs.org

from __future__ import absolute_import, print_function
import os
import sys
import traceback

try:
    # hypothesis 2.x
    from hypothesis.configuration import set_hypothesis_home_dir
    from hypothesis import settings
except ImportError:
    # hypothesis 1.x
    from hypothesis.settings import set_hypothesis_home_dir
    from hypothesis import Settings as settings
import hypothesis.strategies as st
from hypothesis import given

# hypothesis store data regarding generate example and code
set_hypothesis_home_dir(os.path.join(
    os.getenv('TESTTMP'), ".hypothesis"
))

def check(*args, **kwargs):
    """decorator to make a function a hypothesis test

    Decorated function are run immediately (to be used doctest style)"""
    def accept(f):
        # Workaround for https://github.com/DRMacIver/hypothesis/issues/206
        # Fixed in version 1.13 (released 2015 october 29th)
        f.__module__ = '__anon__'
        try:
            with settings(max_examples=2000):
                given(*args, **kwargs)(f)()
        except Exception:
            traceback.print_exc(file=sys.stdout)
            sys.exit(1)
    return accept


def roundtrips(data, decode, encode):
    """helper to tests function that must do proper encode/decode roundtripping
    """
    @given(data)
    def testroundtrips(value):
        encoded = encode(value)
        decoded = decode(encoded)
        if decoded != value:
            raise ValueError(
                "Round trip failed: %s(%r) -> %s(%r) -> %r" % (
                    encode.__name__, value, decode.__name__, encoded,
                    decoded
                ))
    try:
        testroundtrips()
    except Exception:
        # heredoc swallow traceback, we work around it
        traceback.print_exc(file=sys.stdout)
        raise
    print("Round trip OK")


# strategy for generating bytestring that might be an issue for Mercurial
bytestrings = (
    st.builds(lambda s, e: s.encode(e), st.text(), st.sampled_from([
        'utf-8', 'utf-16',
    ]))) | st.binary()