101 lines
2.2 KiB
Python
101 lines
2.2 KiB
Python
# SPDX-License-Identifier: MIT
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import pytest
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import attr
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class TestPatternMatching:
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"""
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Pattern matching syntax test cases.
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"""
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@pytest.mark.parametrize("dec", [attr.s, attr.define, attr.frozen])
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def test_simple_match_case(self, dec):
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"""
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Simple match case statement works as expected with all class
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decorators.
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"""
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@dec
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class C:
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a = attr.ib()
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assert ("a",) == C.__match_args__
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matched = False
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c = C(a=1)
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match c:
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case C(a):
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matched = True
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assert matched
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assert 1 == a
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def test_explicit_match_args(self):
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"""
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Does not overwrite a manually set empty __match_args__.
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"""
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ma = ()
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@attr.define
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class C:
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a = attr.field()
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__match_args__ = ma
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c = C(a=1)
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msg = r"C\(\) accepts 0 positional sub-patterns \(1 given\)"
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with pytest.raises(TypeError, match=msg):
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match c:
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case C(_):
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pass
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def test_match_args_kw_only(self):
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"""
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kw_only classes don't generate __match_args__.
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kw_only fields are not included in __match_args__.
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"""
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@attr.define
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class C:
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a = attr.field(kw_only=True)
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b = attr.field()
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assert ("b",) == C.__match_args__
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c = C(a=1, b=1)
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msg = r"C\(\) accepts 1 positional sub-pattern \(2 given\)"
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with pytest.raises(TypeError, match=msg):
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match c:
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case C(a, b):
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pass
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found = False
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match c:
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case C(b, a=a):
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found = True
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assert found
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@attr.define(kw_only=True)
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class C:
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a = attr.field()
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b = attr.field()
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c = C(a=1, b=1)
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msg = r"C\(\) accepts 0 positional sub-patterns \(2 given\)"
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with pytest.raises(TypeError, match=msg):
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match c:
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case C(a, b):
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pass
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found = False
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match c:
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case C(a=a, b=b):
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found = True
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assert found
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assert (1, 1) == (a, b)
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