test: add subscription_handle unit tests and CI workflow; docs: add test running instructions

Signed-off-by: Giannis <giannisgeorgiadiis@gmail.com>

Author: Giannis-dot

.github/workflows/ci.yml

@@ -0,0 +1,28 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  test-subscription-handle:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: '3.11'
+
+      - name: Install test deps
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install pytest
+
+      - name: Run subscription_handle tests
+        run: |
+          python -m pytest -q tests/test_subscription_handle.py

CONTRIBUTING.md

@@ -166,4 +166,25 @@ 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)
+
+---
+
+## Running tests locally
+
+During development you may want to run a single test file in isolation to avoid importing the project's package-level `__init__` (which imports generated protobuf modules). To run a single test file without loading project-wide fixtures, use the project's virtualenv Python and run pytest on the path:
+
+PowerShell example:
+```powershell
+# activate virtualenv (if not already active)
+C:/Users/Giannis/OneDrive/Programming/hiero-sdk-python/.venv/Scripts/Activate.ps1
+
+# install test deps if needed
+python -m pip install -U pip
+python -m pip install pytest
+
+# run a single test file
+python -m pytest -q tests/test_subscription_handle.py
+```
+
+If you want to run a subset of tests, use `-k` with a keyword expression or provide a directory/file path. This helps avoid heavy `conftest.py` imports during quick iteration.

tests/test_subscription_handle.py

@@ -0,0 +1,38 @@
+from unittest.mock import Mock
+import importlib.util
+from pathlib import Path
+
+# Load the module directly from the source file to avoid importing the
+# package `hiero_sdk_python` (its top-level __init__ triggers imports of
+# many modules that require generated protobufs during test collection).
+repo_root = Path(__file__).resolve().parent.parent
+module_path = repo_root / "src" / "hiero_sdk_python" / "utils" / "subscription_handle.py"
+spec = importlib.util.spec_from_file_location("subscription_handle", str(module_path))
+subscription_handle = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(subscription_handle)
+SubscriptionHandle = subscription_handle.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()