test: add unit test for subscription_handle

CHANGELOG.md

@@ -7,6 +7,7 @@ This changelog is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.
 ## [Unreleased]
 
 ### Added
+- Added unit tests for `SubscriptionHandle` class covering cancellation state, thread management, and join operations.
 - Modularized `transfer_transaction_fungible` example by introducing `account_balance_query()` & `transfer_transaction()`.Renamed `transfer_tokens()` → `main()`
 - Phase 2 of the inactivity-unassign bot:Automatically detects stale open pull requests (no commit activity for 21+ days), comments with a helpful InactivityBot message, closes the stale PR, and unassigns the contributor from the linked issue.
 - Added **str**() to CustomFixedFee and updated examples and tests accordingly.

CONTRIBUTING.md

@@ -166,4 +166,5 @@ Thank you for contributing to the Hiero Python SDK! 🎉
 - **Need help or want to connect?** Join our community on Discord! See the **[Discord Joining Guide](docs/discord.md)** for detailed steps on how to join the LFDT server
 - **Quick Links:**
     - Join the main [Linux Foundation Decentralized Trust (LFDT) Discord Server](https://discord.gg/hyperledger).
-    - Go directly to the [#hiero-python-sdk channel](https://discord.com/channels/905194001349627914/1336494517544681563)
+    - Go directly to the [#hiero-python-sdk channel](https://discord.com/channels/905194001349627914/1336494517544681563)
+

tests/unit/test_subscription_handle.py

@@ -0,0 +1,28 @@
+from unittest.mock import Mock
+
+from hiero_sdk_python.utils.subscription_handle import SubscriptionHandle
+
+
+def test_not_cancelled_by_default():
+    handle = SubscriptionHandle()
+    assert not handle.is_cancelled()
+
+
+def test_cancel_marks_as_cancelled():
+    handle = SubscriptionHandle()
+    handle.cancel()
+    assert handle.is_cancelled()
+
+
+def test_set_thread_and_join_calls_thread_join_with_timeout():
+    handle = SubscriptionHandle()
+    mock_thread = Mock()
+    handle.set_thread(mock_thread)
+    handle.join(timeout=0.25)
+    mock_thread.join.assert_called_once_with(0.25)
+
+
+def test_join_without_thread_raises_nothing():
+    handle = SubscriptionHandle()
+    # should not raise
+    handle.join()

tools/_mypy_minimal.ini

@@ -0,0 +1,2 @@
+[mypy]
+ignore_missing_imports = True