Add node_value & get_node_value to TaskSocket (#299)

Add `node_value` & `get_node_value` to `TaskSocket`. This is basically just syntactic sugar to directly access the associated
raw Python value of a `Socket` which has a orm.Data as its value. Therefore, we can avoid, e.g., `.value.value`.

aiida_workgraph/socket.py

@@ -1,5 +1,8 @@
 from typing import Any, Type
+
+from aiida import orm
 from node_graph.socket import NodeSocket
+
 from aiida_workgraph.property import TaskProperty
 
 
@@ -10,6 +13,22 @@ class TaskSocket(NodeSocket):
     # to override the default NodeProperty from node_graph
     node_property = TaskProperty
 
+    @property
+    def node_value(self):
+        return self.get_node_value()
+
+    def get_node_value(self):
+        """Obtain the actual Python `value` of the object attached to the Socket."""
+        if isinstance(self.value, orm.Data):
+            if hasattr(self.value, "value"):
+                return self.value.value
+            else:
+                raise ValueError(
+                    "Data node does not have a value attribute. We do not know how to extract the raw Python value."
+                )
+        else:
+            return self.value
+
 
 def build_socket_from_AiiDA(DataClass: Type[Any]) -> Type[TaskSocket]:
     """Create a socket class from AiiDA DataClass."""

tests/test_socket.py

@@ -87,3 +87,39 @@ def test(a, b=1, **kwargs):
     test1 = test.node()
     assert test1.inputs["kwargs"].link_limit == 1e6
     assert test1.inputs["kwargs"].identifier == "workgraph.namespace"
+
+
+@pytest.mark.parametrize(
+    "data_type, socket_value, node_value",
+    (
+        (None, None, None),
+        # Check that SocketAny works for int node, without providing type hint
+        (None, 1, 1),
+        (int, 1, 1),
+        (float, 1.0, 1.0),
+        (bool, True, True),
+        (str, "abc", "abc"),
+        (orm.Int, 1, 1),
+        (orm.Float, 1.0, 1.0),
+        (orm.Str, "abc", "abc"),
+        (orm.Bool, True, True),
+    ),
+)
+def test_node_value(data_type, socket_value, node_value):
+
+    wg = WorkGraph()
+
+    def my_task(x: data_type):
+        pass
+
+    my_task1 = wg.add_task(my_task, name="my_task", x=socket_value)
+    socket = my_task1.inputs["x"]
+
+    socket_node_value = socket.get_node_value()
+    assert isinstance(socket_node_value, type(node_value))
+    assert socket_node_value == node_value
+
+    # Check that property also returns the correct results
+    socket_node_value = socket.node_value
+    assert isinstance(socket_node_value, type(node_value))
+    assert socket_node_value == node_value