adds unit test

Author: ibraheem-abe

tests/unit_tests/test_subtensor.py

@@ -2611,6 +2611,97 @@ def test_get_minimum_required_stake_query_failure(mocker, subtensor):
     )
 
 
+def test_get_stake_fee_parameter_handling(mocker, subtensor):
+    """Test get_stake_fee parameter handling, focusing on None cases and tuple creation."""
+    # Mock data
+    fake_hotkey = "hk1"
+    fake_hotkey2 = "hk2"
+    fake_coldkey = "ck1"
+    fake_amount = Balance.from_tao(100)
+    netuid = 1
+    fake_fee = 1_000_000
+
+    # Mock return fee
+    mock_query = mocker.patch.object(
+        subtensor,
+        "query_runtime_api",
+        side_effect=lambda runtime_api, method, params, block: (
+            fake_fee
+            if runtime_api == "StakeInfoRuntimeApi" and method == "get_stake_fee"
+            else None
+        ),
+    )
+
+    # Test Cases
+    test_cases = [
+        # 1. Adding new stake (origin is None)
+        {
+            "name": "new_stake",
+            "params": {
+                "origin_hotkey_ss58": None,
+                "origin_netuid": None,
+                "origin_coldkey_ss58": fake_coldkey,
+                "destination_hotkey_ss58": fake_hotkey,
+                "destination_netuid": netuid,
+                "destination_coldkey_ss58": fake_coldkey,
+                "amount": fake_amount,
+            },
+            "expected_origin": None,
+            "expected_destination": (fake_hotkey, netuid),
+        },
+        # 2. Removing stake (destination is None)
+        {
+            "name": "remove_stake",
+            "params": {
+                "origin_hotkey_ss58": fake_hotkey,
+                "origin_netuid": netuid,
+                "origin_coldkey_ss58": fake_coldkey,
+                "destination_hotkey_ss58": None,
+                "destination_netuid": None,
+                "destination_coldkey_ss58": fake_coldkey,
+                "amount": fake_amount,
+            },
+            "expected_origin": (fake_hotkey, netuid),
+            "expected_destination": None,
+        },
+        # 3. All parameters present
+        {
+            "name": "all_parameters",
+            "params": {
+                "origin_hotkey_ss58": fake_hotkey,
+                "origin_netuid": netuid,
+                "origin_coldkey_ss58": fake_coldkey,
+                "destination_hotkey_ss58": fake_hotkey2,
+                "destination_netuid": netuid,
+                "destination_coldkey_ss58": fake_coldkey,
+                "amount": fake_amount,
+            },
+            "expected_origin": (fake_hotkey, netuid),
+            "expected_destination": (fake_hotkey2, netuid),
+        },
+    ]
+
+    for test_case in test_cases:
+        mock_query.reset_mock()
+
+        result = subtensor.get_stake_fee(**test_case["params"])
+        assert isinstance(result, Balance)
+        assert result == Balance.from_rao(fake_fee)
+
+        mock_query.assert_called_once_with(
+            runtime_api="StakeInfoRuntimeApi",
+            method="get_stake_fee",
+            params=[
+                test_case["expected_origin"],
+                test_case["params"]["origin_coldkey_ss58"],
+                test_case["expected_destination"],
+                test_case["params"]["destination_coldkey_ss58"],
+                test_case["params"]["amount"],
+            ],
+            block=None,
+        )
+
+
 def test_get_minimum_required_stake_invalid_result(mocker, subtensor):
     """Test when the result cannot be decoded."""
     # Mock data