themattrix/bashup

import difflib
import pprint

try:
    # noinspection PyCompatibility
    # pylint: disable=wrong-import-order
    from cStringIO import StringIO
except ImportError:          # pragma: no cover
    # pylint: disable=wrong-import-order
    from io import StringIO  # pragma: no cover

import contextlib2 as contextlib

try:
    # noinspection PyUnresolvedReferences,PyUnboundLocalVariable
    # pylint: disable=invalid-name
    basestring
except NameError:     # pragma: no cover
    # pylint: disable=invalid-name,redefined-builtin
    basestring = str  # pragma: no cover


def diff(actual, expected):
    p_actual = (
        actual if isinstance(actual, basestring) else
        pprint.pformat(actual))     # pragma: no cover

    p_expect = (
        expected if isinstance(expected, basestring) else
        pprint.pformat(expected))   # pragma: no cover

    return '\n'.join(difflib.unified_diff(
        p_actual.splitlines(),
        p_expect.splitlines(),
        fromfile='actual',
        tofile='expected'))  # pragma: no cover


def assert_eq(actual, expected):
    try:
        assert actual == expected
    except AssertionError:                  # pragma: no cover
        raise AssertionError(
            '\n' + diff(actual, expected))  # pragma: no cover


@contextlib.contextmanager
def captured_stdout():
    stdout = StringIO()
    with contextlib.redirect_stdout(stdout):
        yield stdout