tests: add various tests for PythonTask.__dict__ access

tests/event/test_pythontask.py

@@ -0,0 +1,78 @@
+from panda3d.core import PythonTask
+import pytest
+import types
+import sys
+
+
+def test_pythontask_property_builtin():
+    task = PythonTask()
+
+    # Read-write property
+    assert task.name == ""
+    task.name = "ABC"
+
+    # Read-only property
+    assert task.dt == 0.0
+    with pytest.raises(AttributeError):
+        task.dt = 1.0
+    assert task.dt == 0.0
+
+    # Non-existent property
+    with pytest.raises(AttributeError):
+        task.abc
+
+
+def test_pythontask_property_custom():
+    task = PythonTask()
+    assert not hasattr(task, 'custom_field')
+
+    task.custom_field = 1.0
+    assert hasattr(task, 'custom_field')
+    assert task.custom_field == 1.0
+
+    task.custom_field = 2.0
+    assert task.custom_field == 2.0
+
+    del task.custom_field
+    assert not hasattr(task, 'custom_field')
+
+
+def test_pythontask_property_override():
+    task = PythonTask()
+    assert isinstance(task.gather, types.BuiltinMethodType)
+
+    task.gather = 123
+    assert task.gather == 123
+
+    del task.gather
+    assert isinstance(task.gather, types.BuiltinMethodType)
+
+
+def test_pythontask_dict_get():
+    task = PythonTask()
+
+    d = task.__dict__
+    rc1 = sys.getrefcount(d)
+
+    task.__dict__
+    task.__dict__
+
+    rc2 = sys.getrefcount(d)
+
+    assert rc1 == rc2
+
+
+def test_pythontask_dict_set():
+    task = PythonTask()
+    d = {}
+
+    rc1 = sys.getrefcount(d)
+    task.__dict__ = d
+    rc2 = sys.getrefcount(d)
+
+    assert rc1 + 1 == rc2
+
+    task.__dict__ = {}
+    rc2 = sys.getrefcount(d)
+
+    assert rc1 == rc2