Add tests for resource duplication

modules/gdscript/tests/scripts/runtime/features/duplicate_resource.gd

@@ -0,0 +1,40 @@
+# We could use @export_custom to really test every property usage, but we know for good
+# that duplicating scripted properties flows through the same code already thoroughly tested
+# in the [Resource] test cases. The same goes for all the potential deep duplicate modes.
+# Therefore, it's enough to ensure the exported scriped properties are copied when invoking
+# duplication by each entry point.
+class TestResource:
+	extends Resource
+	@export var text: String = "holaaa"
+	@export var arr: Array = [1, 2, 3]
+	@export var dict: Dictionary = { "a": 1, "b": 2 }
+
+func test():
+	# Via Resource type.
+	var res := TestResource.new()
+	var dupe: TestResource
+
+	dupe = res.duplicate()
+	print(dupe.text)
+	print(dupe.arr)
+	print(dupe.dict)
+
+	dupe = res.duplicate_deep()
+	print(dupe.text)
+	print(dupe.arr)
+	print(dupe.dict)
+
+	# Via Variant type.
+
+	var res_var = TestResource.new()
+	var dupe_var
+
+	dupe_var = res_var.duplicate()
+	print(dupe_var.text)
+	print(dupe_var.arr)
+	print(dupe_var.dict)
+
+	dupe_var = res_var.duplicate_deep()
+	print(dupe_var.text)
+	print(dupe_var.arr)
+	print(dupe_var.dict)

modules/gdscript/tests/scripts/runtime/features/duplicate_resource.out

@@ -0,0 +1,13 @@
+GDTEST_OK
+holaaa
+[1, 2, 3]
+{ "a": 1, "b": 2 }
+holaaa
+[1, 2, 3]
+{ "a": 1, "b": 2 }
+holaaa
+[1, 2, 3]
+{ "a": 1, "b": 2 }
+holaaa
+[1, 2, 3]
+{ "a": 1, "b": 2 }