Regression Testing

Regression testing is a crucial aspect of the software development life cycle, particularly in the context of DevOps. It involves retesting a modified or updated software system to ensure that any changes or new features haven’t introduced unintended side effects or broken existing functionalities. Regression testing aims to catch any regressions, which are defects that reoccur after changes have been made.

Workflows:

1. Identify regression test cases: Start by identifying the test cases that cover critical functionalities and areas of the software affected by recent changes. These test cases should focus on both positive and negative scenarios to ensure comprehensive coverage.
2. Create or update test scripts: Based on the identified test cases, create or update the necessary test scripts. These scripts should include steps to replicate specific scenarios, input data, and expected results.
3. Execute regression tests: Run the regression test suite against the modified software system. This can be done manually or automated, depending on the complexity of the system and available resources.
4. Compare actual results with expected results: After executing the test suite, compare the actual results with the expected results specified in the test scripts. Identify any deviations or failures.
5. Log and analyze issues: If any failures or deviations are found, log them as defects or issues in a tracking system. Analyze the root cause of the failures and determine if they are indeed regressions or if they require separate investigation.
6. Debug and fix issues: Developers should investigate the reported issues and fix the defects causing the regressions. Once the fixes are implemented, the process of regression testing can be repeated to validate the fixes and ensure the absence of further regressions.

Code examples and usage examples:

1. Automated regression testing with Selenium (Python):

import unittest
from selenium import webdriver

class RegressionTest(unittest.TestCase):
    def setUp(self):
        self.driver = webdriver.Chrome()

    def test_login(self):
        self.driver.get("https://example.com")
        # Perform login actions
        # Assert login success

    def test_checkout(self):
        self.driver.get("https://example.com/cart")
        # Add items to cart
        # Proceed to checkout
        # Assert successful checkout

    def tearDown(self):
        self.driver.quit()

if __name__ == "__main__":
    unittest.main()

In this example, the code utilizes the Selenium library in Python to automate browser interactions. The RegressionTest class contains test methods test_login and test_checkout, which simulate user actions and make assertions to verify the expected outcomes. These tests can be executed as part of an automated regression testing suite.

2. Manual regression testing checklist:

Test Case: User Registration

1. Verify that a new user can register successfully.
   - Enter valid user details (name, email, password).
   - Click on the "Register" button.
   - Verify the user is redirected to the login page.
   - Verify the user receives a registration confirmation email.

2. Verify that duplicate registration is not allowed.
   - Enter an email address that is already registered.
   - Click on the "Register" button.
   - Verify an appropriate error message is displayed.

3. Verify that mandatory fields are validated.
   - Leave any mandatory field empty.
   - Click on the "Register" button.
   - Verify appropriate error messages are displayed for each empty field.

4. Verify that password complexity is enforced.
   - Enter a password that doesn't meet the complexity requirements.
   - Click on the "Register" button.
   - Verify an appropriate error message is displayed.

In this example, a manual regression testing checklist is provided for testing the user registration functionality. Each test case outlines the steps to be performed, the expected outcomes, and any specific scenarios to cover.

Both automated and manual regression testing approaches have their merits and can be utilized based on the project’s requirements, time constraints, and available resources. The choice between them depends on factors such as the complexity of the software, the need for frequent regression testing, and the level of test coverage desired.