Add tests for opt_frozen_dataclass

pytools/test/test_dataclasses.py

@@ -0,0 +1,104 @@
+__copyright__ = "Copyright (C) 2024 University of Illinois Board of Trustees"
+
+__license__ = """
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+"""
+
+
+import sys
+
+import pytest
+
+from pytools import opt_frozen_dataclass
+
+
+def test_opt_frozen_dataclass() -> None:
+    # {{{ basic usage
+
+    @opt_frozen_dataclass()
+    class A:
+        x: int
+
+    a = A(1)
+    assert a.x == 1
+
+    # Needs to be hashable by default, not using object.__hash__
+    hash(a)
+    assert hash(a) == hash(A(1))
+    assert a == A(1)
+
+    # Needs to be frozen by default
+    with pytest.raises(AttributeError):
+        a.x = 2  # type: ignore[misc]
+
+    assert a.__dataclass_params__.frozen is True  # type: ignore[attr-defined]  # pylint: disable=no-member
+
+    # }}}
+
+    with pytest.raises(TypeError):
+        # Can't specify frozen parameter
+        @opt_frozen_dataclass(frozen=False)  # type: ignore[call-arg]  # pylint: disable=unexpected-keyword-arg
+        class B:
+            x: int
+
+    # {{{ eq=False
+
+    @opt_frozen_dataclass(eq=False)
+    class C:
+        x: int
+
+    c = C(1)
+
+    # Hashing still works, but uses object.__hash__ (i.e., id())
+    assert hash(c) != hash(C(1))
+
+    # Equality is not defined and uses id()
+    assert c != C(1)
+
+    # }}}
+
+
+def test_dataclass_weakref() -> None:
+    if sys.version_info < (3, 11):
+        pytest.skip("weakref support needs Python 3.11+")
+
+    @opt_frozen_dataclass(weakref_slot=True, slots=True)
+    class Weakref:
+        x: int
+
+    a = Weakref(1)
+    assert a.x == 1
+
+    import weakref
+    ref = weakref.ref(a)
+
+    _ = ref().x
+
+    with pytest.raises(TypeError):
+        @opt_frozen_dataclass(weakref_slot=True)  # needs slots=True to work
+        class Weakref2:
+            x: int
+
+
+if __name__ == "__main__":
+    if len(sys.argv) > 1:
+        exec(sys.argv[1])
+    else:
+        from pytest import main
+        main([__file__])