Extend the tests

filmor · filmor · commit f6a69684c1f9 · 2026-05-05T21:56:54.000+02:00
diff --git a/src/testing/dlrtest.cs b/src/testing/dlrtest.cs
@@ -1,31 +1,45 @@
+using System;
 using System.Collections.Generic;
 using System.Dynamic;
 
 namespace Python.Test;
 
 public class DynamicMappingObject : DynamicObject
 {
-    readonly Dictionary<string, object> storage = [];
+    Dictionary<string, object> storage;
+
+    Dictionary<string, object> Storage => storage ??= [];
 
     // Native members for testing that regular CLR access is unaffected.
     public string Label = "default";
     public int Multiplier { get; set; } = 1;
     public int Multiply(int value) => value * Multiplier;
 
     // Test helper: bypass normal member binding and write directly to dynamic storage.
-    public void SetDynamicValue(string name, object value) => storage[name] = value;
+    public void SetDynamicValue(string name, object value) => Storage[name] = value;
+
+    // Test helper: retrieve the actual value stored in C# (for verification that None was stored as null)
+    public object GetDynamicValue(string name) => Storage.TryGetValue(name, out var value) ? value : null;
+
+
 
     public override bool TryGetMember(GetMemberBinder binder, out object result)
-        => storage.TryGetValue(binder.Name, out result);
+        => Storage.TryGetValue(binder.Name, out result);
+
+    public object TestProp 
+    { 
+        get => "TEST_PROP"; 
+        set => throw new InvalidOperationException("Can't write to TestProp"); 
+    }
 
     public override bool TrySetMember(SetMemberBinder binder, object value)
     {
-        storage[binder.Name] = value;
+        Storage[binder.Name] = value;
         return true;
     }
 
     public override bool TryDeleteMember(DeleteMemberBinder binder)
-        => storage.Remove(binder.Name);
+        => binder is not null && Storage.Remove(binder.Name);
 
-    public override IEnumerable<string> GetDynamicMemberNames() => storage.Keys;
+    public override IEnumerable<string> GetDynamicMemberNames() => Storage.Keys;
 }
diff --git a/tests/test_dynamic.py b/tests/test_dynamic.py
@@ -65,3 +65,66 @@ def test_dynamic_and_native_members_coexist():
     assert obj.answer == 42
     assert obj.Multiplier == 2
     assert obj.Multiply(10) == 20
+
+
+@pytest.mark.parametrize("obj", [DynamicMappingObject(), ExpandoObject()])
+def test_set_and_get_dynamic_property(obj):
+    """Test that setting and getting dynamic properties goes through DLR binder."""
+    # Get initial value (should be None for non-existent property)
+    assert not hasattr(obj, "MyProp")
+    
+    # Set a dynamic property to a value
+    obj.MyProp = 42
+    assert obj.MyProp == 42
+    
+    # Set to None and verify it stays None through DLR
+    obj.MyProp = None
+    assert obj.MyProp is None
+    
+    # Set to another value and verify
+    obj.MyProp = "hello"
+    assert obj.MyProp == "hello"
+
+
+def test_update_dynamic_value():
+    """Setting from Python must update the backing dynamic store in C#."""
+    obj = DynamicMappingObject()
+    obj.SetDynamicValue("TestProp", "initial")
+    assert obj.TestProp == "initial"
+
+    obj.TestProp = None
+
+    assert obj.TestProp is None
+    assert obj.GetDynamicValue("TestProp") is None
+
+
+def test_derive_from_dynamic_class():
+    class MyMappingObject(DynamicMappingObject):
+        __namespace__ = "PythonNetTest"
+
+        def __init__(self):
+            self._custom = 0
+
+        @property
+        def custom_property(self):
+            return self._custom
+        
+        @custom_property.setter
+        def custom_property(self, i):
+            self._custom += i
+
+
+    obj = MyMappingObject()
+    with pytest.raises(AttributeError):
+        x = obj.unknown_property
+
+    assert obj.custom_property == 0
+
+    obj.custom_property = 5
+    assert obj.custom_property == 5
+
+    obj.custom_property = 5
+    assert obj.custom_property == 10
+
+    obj.other_property = None
+    assert obj.other_property is None
