refactor: update MQTT client tests to use mock methods for packet handling

.github/workflows/ci.yml

@@ -0,0 +1,43 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+  workflow_dispatch:  # Allow manual triggering
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    
+    steps:
+    - uses: actions/checkout@v3
+    
+    - name: Set up Python 3.12
+      uses: actions/setup-python@v4
+      with:
+        python-version: '3.12'
+    
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -r requirements.txt
+    
+    - name: Check code formatting with Black
+      run: |
+        black --check .
+    
+    - name: Run tests with pytest
+      run: |
+        python -m pytest
+    
+    - name: Run tests with coverage
+      run: |
+        python -m pytest --cov=src.esp_sensors --cov-report=xml
+    
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v3
+      with:
+        file: ./coverage.xml
+        fail_ci_if_error: false