summaryrefslogtreecommitdiffstats
path: root/contrib/python/PyHamcrest/py3/hamcrest/library/collection/is_empty.py
blob: cff60d636d0516333aa4e337b5c613744096d997 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
from typing import Optional, Sized

from hamcrest.core.base_matcher import BaseMatcher
from hamcrest.core.description import Description
from hamcrest.core.matcher import Matcher

__author__ = "Chris Rose"
__copyright__ = "Copyright 2012 hamcrest.org"
__license__ = "BSD, see License.txt"


class IsEmpty(BaseMatcher[Sized]):
    def matches(self, item: Sized, mismatch_description: Optional[Description] = None) -> bool:
        try:
            if len(item) == 0:
                return True

            if mismatch_description:
                mismatch_description.append_text("has %d item(s)" % len(item))

        except TypeError:
            if mismatch_description:
                mismatch_description.append_text("does not support length")

        return False

    def describe_to(self, description: Description) -> None:
        description.append_text("an empty collection")


def empty() -> Matcher[Sized]:
    """
    This matcher matches any collection-like object that responds to the
    __len__ method, and has a length of 0.
    """
    return IsEmpty()