view tests/hypothesishelpers.py @ 51925:3a90a6fd710d

dirstate: subclass the new dirstate Protocol class

Behold the chaos that ensues.  We'll use the generated *.pyi files to apply type
annotations to the interface, and see how much agrees with the documentation.

Since the CamelCase name was used to try to work around pytype issues with zope
interfaces and is a new innovation this cycle (see c1d7ac70980b), drop the
CamelCase name.  I think the Protocol classes *should* be CamelCase, but that
can be done later in one pass.  For now, the CamelCase alias is extra noise in
the *.pyi files.

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

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()