Viewing file:  is_empty.py (1.05 KB) -rw-r--r--
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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()
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