Adds test

Author: thewhaleking

tests/e2e_tests/test_children_hotkeys.py

@@ -0,0 +1,15 @@
+import pytest
+
+from bittensor_cli.src.bittensor.subtensor_interface import SubtensorInterface
+from bittensor_cli.src.commands.stake.children_hotkeys import (
+    get_childkey_completion_block,
+)
+
+
+@pytest.mark.asyncio
+async def test_get_childkey_completion_block(local_chain):
+    async with SubtensorInterface("ws://127.0.0.1:9945") as subtensor:
+        current_block, completion_block = await get_childkey_completion_block(
+            subtensor, 1
+        )
+        assert (completion_block - current_block) >= 7200