Function expect

tests/_util.py:75–107

Run ``invocation`` via ``program`` and expect resulting output to match. May give one or both of ``out``/``err`` (but not neither). ``program`` defaults to ``Program()``. To skip automatically assuming the argv under test starts with ``"invoke "``, say ``invoke=False``.

(
    invocation, out=None, err=None, program=None, invoke=True, test=None
)

def expect(
    invocation, out=None, err=None, program=None, invoke=True, test=None
):
    """
    Run ``invocation`` via ``program`` and expect resulting output to match.

    May give one or both of ``out``/``err`` (but not neither).

    ``program`` defaults to ``Program()``.

    To skip automatically assuming the argv under test starts with ``"invoke
    "``, say ``invoke=False``.

    To customize the operator used for testing (default: equality), use
    ``test`` (which should be an assertion wrapper of some kind).
    """
    stdout, stderr = run(invocation, program, invoke)
    # Perform tests
    if out is not None:
        if test:
            test(stdout, out)
        else:
            assert out == stdout
    if err is not None:
        if test:
            test(stderr, err)
        else:
            assert err == stderr
    # Guard against silent failures; since we say exit=False this is the only
    # real way to tell if stuff died in a manner we didn't expect.
    elif stderr:
        assert False, "Unexpected stderr: {}".format(stderr)
    return stdout, stderr


class MockSubprocess: