test_lambda_formatting.py

# This file is part of Hypothesis, which may be found at
# https://github.com/HypothesisWorks/hypothesis/
#
# Copyright the Hypothesis Authors.
# Individual contributors are listed in AUTHORS.rst and the git log.
#
# This Source Code Form is subject to the terms of the Mozilla Public License,
# v. 2.0. If a copy of the MPL was not distributed with this file, You can
# obtain one at https://mozilla.org/MPL/2.0/.

from hypothesis.internal.reflection import get_pretty_function_description


def test_bracket_whitespace_is_striped():
    assert get_pretty_function_description(lambda x: (x + 1)) == "lambda x: (x + 1)"


def test_no_whitespace_before_colon_with_no_args():
    assert get_pretty_function_description(eval("lambda: None")) == "lambda: <unknown>"


def test_can_have_unicode_in_lambda_sources():
    t = lambda x: "é" not in x
    assert get_pretty_function_description(t) == 'lambda x: "é" not in x'


# fmt: off
ordered_pair = (
    lambda right: [].map(
        lambda length: ()))
# fmt: on


def test_can_get_descriptions_of_nested_lambdas_with_different_names():
    assert (
        get_pretty_function_description(ordered_pair)
        == "lambda right: [].map(lambda length: ())"
    )


def test_does_not_error_on_unparsable_source():
    # fmt: off
    t = [
        lambda x: \
        # This will break ast.parse, but the brackets are needed for the real
        # parser to accept this lambda
        x][0]
    # fmt: on
    assert get_pretty_function_description(t) == "lambda x: <unknown>"


def test_source_of_lambda_is_pretty():
    assert get_pretty_function_description(lambda x: True) == "lambda x: True"


def test_variable_names_are_not_pretty():
    t = lambda x: True
    assert get_pretty_function_description(t) == "lambda x: True"


def test_does_not_error_on_dynamically_defined_functions():
    x = eval("lambda t: 1")
    get_pretty_function_description(x)


def test_collapses_whitespace_nicely():
    # fmt: off
    t = (
        lambda x,       y:           1
    )
    # fmt: on
    assert get_pretty_function_description(t) == "lambda x, y: 1"


def test_is_not_confused_by_tuples():
    p = (lambda x: x > 1, 2)[0]

    assert get_pretty_function_description(p) == "lambda x: x > 1"


def test_strips_comments_from_the_end():
    t = lambda x: 1  # A lambda comment
    assert get_pretty_function_description(t) == "lambda x: 1"


def test_does_not_strip_hashes_within_a_string():
    t = lambda x: "#"
    assert get_pretty_function_description(t) == 'lambda x: "#"'


def test_can_distinguish_between_two_lambdas_with_different_args():
    a, b = (lambda x: 1, lambda y: 2)
    assert get_pretty_function_description(a) == "lambda x: 1"
    assert get_pretty_function_description(b) == "lambda y: 2"


def test_does_not_error_if_it_cannot_distinguish_between_two_lambdas():
    a, b = (lambda x: 1, lambda x: 2)
    assert "lambda x:" in get_pretty_function_description(a)
    assert "lambda x:" in get_pretty_function_description(b)


def test_lambda_source_break_after_def_with_brackets():
    # fmt: off
    f = (lambda n:
         'aaa')
    # fmt: on

    source = get_pretty_function_description(f)
    assert source == "lambda n: 'aaa'"


def test_lambda_source_break_after_def_with_line_continuation():
    # fmt: off
    f = lambda n:\
        'aaa'
    # fmt: on

    source = get_pretty_function_description(f)
    assert source == "lambda n: 'aaa'"


def arg_decorator(*s):
    def accept(f):
        return s

    return accept


@arg_decorator(lambda x: x + 1)
def plus_one():
    pass


@arg_decorator(lambda x: x + 1, lambda y: y * 2)
def two_decorators():
    pass


def test_can_extract_lambda_repr_in_a_decorator():
    assert get_pretty_function_description(plus_one[0]) == "lambda x: x + 1"


def test_can_extract_two_lambdas_from_a_decorator_if_args_differ():
    a, b = two_decorators
    assert get_pretty_function_description(a) == "lambda x: x + 1"
    assert get_pretty_function_description(b) == "lambda y: y * 2"


@arg_decorator(lambda x: x + 1)
def decorator_with_space():
    pass


def test_can_extract_lambda_repr_in_a_decorator_with_spaces():
    assert get_pretty_function_description(decorator_with_space[0]) == "lambda x: x + 1"


@arg_decorator(lambda: ())
def to_brackets():
    pass


def test_can_handle_brackets_in_decorator_argument():
    assert get_pretty_function_description(to_brackets[0]) == "lambda: ()"


def identity(x):
    return x


@arg_decorator(identity(lambda x: x + 1))
def decorator_with_wrapper():
    pass


def test_can_handle_nested_lambda_in_decorator_argument():
    assert (
        get_pretty_function_description(decorator_with_wrapper[0]) == "lambda x: x + 1"
    )