Tuple single value compatibility PolkadotJS

Author: arjanz

scalecodec/types.py

@@ -288,13 +288,17 @@ def decode(self, data: ScaleBytes) -> tuple:
             scale_obj = scale_def.new()
 
             scale_obj.decode(data)
+
+            if len(self.values) == 1:
+                return scale_obj
+
             value += (scale_obj,)
 
         return value
 
-    def serialize(self, value: tuple) -> tuple:
-        if len(value) == 1:
-            return value[0].value
+    def serialize(self, value: Union[tuple, ScaleType]) -> tuple:
+        if issubclass(value.__class__, ScaleType):
+            return value.value
 
         return tuple((i.value for i in value))
 

test/test_tuple.py

@@ -42,6 +42,13 @@ def test_tuple_deserialize(self):
         obj.deserialize((3, 2))
         self.assertEqual(obj.value, (3, 2))
 
+    def test_tuple_single_value(self):
+        # PolkadotJS compatilibity
+        obj = Tuple(U8).new()
+        obj.decode(ScaleBytes('0x03'))
+        self.assertEqual(obj.value, 3)
+        self.assertEqual(obj.value_object, U8.new(value=3))
+
 
 if __name__ == '__main__':
     unittest.main()