Add unit test for fix

libs/core/tests/unit_tests/runnables/test_runnable.py

@@ -5452,3 +5452,37 @@ def test_runnable_assign() -> None:
 
     result = runnable_assign.invoke({"input": 5})
     assert result == {"input": 5, "add_step": {"added": 15}}
+
+def test_runnable_typed_dict_schema() -> None:
+    """Testing that the schema is generated properly(not empty) when using TypedDict
+
+    subclasses to annotate the arguments of a RunnableParallel children.
+    """
+    from typing_extensions import TypedDict
+    from langchain_core.runnables import RunnableParallel, RunnableLambda
+
+    class Foo(TypedDict):
+        foo: str
+
+    class InputData(Foo):
+        bar: str
+
+    def forward_foo(input_data: InputData):
+        return input_data["foo"]
+
+    def transform_input(input_data: InputData):
+        foo = input_data["foo"]
+        bar = input_data["bar"]
+
+        return {
+            "transformed": foo + bar
+        }
+
+    foo_runnable = RunnableLambda(forward_foo)
+    other_runnable = RunnableLambda(transform_input)
+
+    parallel = RunnableParallel(
+        foo=foo_runnable,
+        other=other_runnable,
+    )
+    assert(repr(parallel.input_schema.validate({ "foo": "Y", "bar": "Z" })) == "RunnableParallel<foo,other>Input(root={'foo': 'Y', 'bar': 'Z'})")