pyhamcrest 包含字典列表的匹配器

Question

为什么 pyhamcrest 失败 contains() 2 个或更多字典列表的匹配器，但适用于 1 个字典列表？

为字典列表编写 hamcrest (pyhamcrest) 匹配器的最佳方法是什么？

在此单元测试示例中，第一个测试通过，第二个测试失败。

import unittest
from hamcrest import contains, assert_that, has_entries

class ContainsTest(unittest.TestCase):

    dict1, dict2 = {"a": 1, "b": 2}, {"a": 1, "b": 2}
    sequence1, sequence2 = list(), list()
    sequence1.append(dict1)
    sequence2.append(dict1)
    sequence2.append(dict2)

    @staticmethod
    def test_sequence():
        assert_that(ContainsTest.sequence1, contains(has_entries({'a': 1, 'b': 2})))
        assert_that(ContainsTest.sequence2, contains(has_entries({'a': 1, 'b': 2})))


if __name__ == "__main__":  
    ContainsTest.test_sequence()

单元测试输出：

File "/usr/local/lib/python3.6/site-packages/hamcrest/core/assert_that.py", 
line 57, in _assert_match raise AssertionError(description) 
AssertionError:  
Expected: a sequence containing [a dictionary containing {'a': <1>, 'b': <2>}]
but: Not matched: <{'a': 1, 'b': 2}>

Ran 1 test in 0.027s
FAILED (failures=1)
Process finished with exit code 1

Answer 1

您正在寻找 has_item，而不是 contains。

有点令人困惑，PyHamcrest 的 contains 并不是 __contains__ 魔术方法意义上的遏制检查。它的语义是模仿原始 Hamcrest 的 contains matcher。它不是在测试列表中的某些元素是否与给定的匹配器匹配；它希望每个列表元素都有一个单独的匹配器，并将匹配器应用于列表的相应元素。 has_item 是检查某些项目是否匹配的。

引用 docs:

Matches if sequence’s elements satisfy a given list of matchers, in order.

Parameters: match1,... – A comma-separated list of matchers.
This matcher iterates the evaluated sequence and a given list of matchers, seeing if each element satisfies its corresponding matcher.

Any argument that is not a matcher is implicitly wrapped in an equal_to matcher to check for equality.

您已经为包含两个元素的列表提供了一个匹配器。 PyHamcrest 需要两个匹配器。第二个字典没有得到匹配。

pyhamcrest 包含字典列表的匹配器

pyhamcrest contains matcher for list of dicts

python

dictionary

python-unittest

pyhamcrest