Fix and improve error handling for missing or invalid configuration file

.github/workflows/unit_tests.yml

@@ -0,0 +1,59 @@
+---
+# This workflow will install Python dependencies
+# and run unit tests for given OSes
+
+name: Unit tests
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: 'ubuntu-latest'
+            python-version: '3.7'
+            rf-version: '3.2.2'
+          - os: 'ubuntu-latest'
+            python-version: '3.8'
+            rf-version: '4.1.3'
+          - os: 'ubuntu-latest'
+            python-version: '3.9'
+            rf-version: '5.0.1'
+          - os: 'ubuntu-latest'
+            python-version: '3.10'
+            rf-version: '6.1.1'
+          - os: 'ubuntu-latest'
+            python-version: '3.11'
+            rf-version: '6.1.1'
+          - os: 'ubuntu-latest'
+            python-version: '3.12'
+            rf-version: '7.0a1'
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 2
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install robotframework==${{ matrix.rf-version }} coverage pytest
+          pip install .
+
+      - name: Run unit tests with coverage
+        run:
+          coverage run -m pytest
+
+      - name: Codecov
+        uses: codecov/codecov-action@v3
+        with:
+          name: ${{ matrix.python-version }}-${{ matrix.os }}-${{ matrix.rf-version }}

src/DatabaseLibrary/connection_manager.py

@@ -13,14 +13,11 @@
 #  limitations under the License.
 
 import importlib
+from configparser import ConfigParser, NoOptionError, NoSectionError
 from dataclasses import dataclass
+from pathlib import Path
 from typing import Any, Dict, Optional
 
-try:
-    import ConfigParser
-except:
-    import configparser as ConfigParser
-
 from robot.api import logger
 
 
@@ -81,6 +78,35 @@ def __iter__(self):
         return iter(self._connections.values())
 
 
+class ConfigReader:
+    def __init__(self, config_file: Optional[str], alias: str):
+        if config_file is None:
+            config_file = "./resources/db.cfg"
+        self.alias = alias
+        self.config = self._load_config(config_file)
+
+    @staticmethod
+    def _load_config(config_file: str) -> Optional[ConfigParser]:
+        config_path = Path(config_file)
+        if not config_path.exists():
+            return None
+        config = ConfigParser()
+        config.read([config_path])
+        return config
+
+    def get(self, param: str) -> str:
+        if self.config is None:
+            raise ValueError(f"Required '{param}' parameter was not provided in keyword arguments.") from None
+        try:
+            return self.config.get(self.alias, param)
+        except NoSectionError:
+            raise ValueError(f"Configuration file does not have [{self.alias}] section.") from None
+        except NoOptionError:
+            raise ValueError(
+                f"Required '{param}' parameter missing in both keyword arguments and configuration file."
+            ) from None
+
+
 class ConnectionManager:
     """
     Connection Manager handles the connection & disconnection to the database.
@@ -153,18 +179,14 @@ def connect_to_database(
         | # uses explicit `dbapiModuleName` and `dbName` but uses the `dbUsername` and `dbPassword` in './resources/db.cfg' |
         | Connect To Database | psycopg2 | my_db_test |
         """
-
-        if dbConfigFile is None:
-            dbConfigFile = "./resources/db.cfg"
-        config = ConfigParser.ConfigParser()
-        config.read([dbConfigFile])
-
-        dbapiModuleName = dbapiModuleName or config.get(alias, "dbapiModuleName")
-        dbName = dbName or config.get(alias, "dbName")
-        dbUsername = dbUsername or config.get(alias, "dbUsername")
-        dbPassword = dbPassword if dbPassword is not None else config.get(alias, "dbPassword")
-        dbHost = dbHost or config.get(alias, "dbHost") or "localhost"
-        dbPort = int(dbPort or config.get(alias, "dbPort"))
+        config = ConfigReader(dbConfigFile, alias)
+
+        dbapiModuleName = dbapiModuleName or config.get("dbapiModuleName")
+        dbName = dbName or config.get("dbName")
+        dbUsername = dbUsername or config.get("dbUsername")
+        dbPassword = dbPassword if dbPassword is not None else config.get("dbPassword")
+        dbHost = dbHost or config.get("dbHost") or "localhost"
+        dbPort = int(dbPort if dbPort is not None else config.get("dbPort"))
 
         if dbapiModuleName == "excel" or dbapiModuleName == "excelrw":
             db_api_module_name = "pyodbc"

test/tests/utests/test_connection_manager.py

@@ -0,0 +1,48 @@
+import re
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from DatabaseLibrary.connection_manager import ConnectionManager
+
+TEST_DATA = Path(__file__).parent / "test_data"
+
+
+class TestConnectWithConfigFile:
+    def test_connect_with_empty_config(self):
+        conn_manager = ConnectionManager()
+        config_path = str(TEST_DATA / "empty.cfg")
+        with pytest.raises(ValueError, match=re.escape("Configuration file does not have [default] section.")):
+            conn_manager.connect_to_database("my_client", dbConfigFile=config_path)
+
+    def test_connect_no_params_no_config(self):
+        conn_manager = ConnectionManager()
+        with pytest.raises(ValueError, match="Required 'dbName' parameter was not provided in keyword arguments."):
+            conn_manager.connect_to_database("my_client")
+
+    def test_connect_missing_option(self):
+        conn_manager = ConnectionManager()
+        config_path = str(TEST_DATA / "no_option.cfg")
+        with pytest.raises(
+            ValueError,
+            match="Required 'dbPassword' parameter missing in both keyword arguments and configuration file.",
+        ):
+            conn_manager.connect_to_database("my_client", dbConfigFile=config_path)
+
+    def test_aliased_section(self):
+        conn_manager = ConnectionManager()
+        config_path = str(TEST_DATA / "alias.cfg")
+        with patch("importlib.import_module", new=MagicMock()) as client:
+            conn_manager.connect_to_database(
+                "my_client",
+                dbUsername="name",
+                dbPassword="password",
+                dbHost="host",
+                dbPort=0,
+                dbConfigFile=config_path,
+                alias="alias2",
+            )
+            client.return_value.connect.assert_called_with(
+                database="example", user="name", password="password", host="host", port=0
+            )

test/tests/utests/test_data/alias.cfg

@@ -0,0 +1,2 @@
+[alias2]
+dbName = example

test/tests/utests/test_data/no_option.cfg

@@ -0,0 +1,3 @@
+[default]
+dbName = example
+dbUsername = example