Add CI to run UTs & linting

This CI workflow will start unit tests and check code formatting when creating PR towards master branch or after merging PR towards master branch

.github/workflows/tests.yml

@@ -0,0 +1,30 @@
+name: Run unit tests
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python 3.10
+      uses: actions/setup-python@v2
+      with:
+        python-version: "3.10"
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install .[dev]
+        pip install flake8
+    - name: Lint with flake8
+      run: |
+        flake8 src tests --count --select=E9,F63,F7,F82 --show-source --statistics --exit-zero
+        flake8 src tests --exclude tests/banker/parser/test_data --count --max-complexity=10 --max-line-length=127 --statistics --exit-zero
+    - name: Test with pytest
+      run: |
+        pytest tests

src/banker/parser/html_transactions_parser.py

@@ -16,7 +16,7 @@ def __parse_transactions_table(self, content: str) -> pandas.DataFrame | None:
             tables = pandas.read_html(io.StringIO(content), attrs={'id': 'lista_transakcji'})
             return tables[0]
         except ValueError:
-            self.logger.warning(f"Invalid HTML literal, transactions table is missing")
+            self.logger.warning("Invalid HTML literal, transactions table is missing")
             return None
 
     def parse_transactions(self, content: str) -> list[Transaction]: