Regression testing

Introduction

In the world of software development, ensuring that a software system continues to function properly after changes is crucial. This is where regression testing comes into play. Regression testing involves re-running functional and non-functional tests to verify that previously developed and tested software still performs as expected after a change. In this article, we will explore the importance of regression testing, the scenarios that require it, and the benefits of incorporating test automation and change impact analysis.

Understanding Regression Testing

Regression testing is a vital part of the software development life cycle. It helps in identifying and fixing issues that may arise due to changes made to the software. These changes can include bug fixes, software enhancements, configuration modifications, or even the substitution of electronic components. By re-running tests that have already been performed, regression testing ensures that the software remains stable and functions correctly.
Why is Regression Testing Important?

Detecting Regression Issues: Changes made to software can inadvertently introduce new bugs or cause existing functionality to break. Regression testing helps in identifying these issues early on, allowing developers to address them promptly before they impact end-users.

Ensuring Software Stability: By re-running tests, regression testing ensures that no unintended side effects occur as a result of changes made to the software. This helps in maintaining the stability and reliability of the software system.

Validating Bug Fixes: When a bug is reported and fixed, regression testing is performed to validate the fix. This ensures that the bug has been successfully resolved and that the software continues to function correctly after the fix is implemented.

Supporting Continuous Integration and Deployment: In agile development environments, where frequent changes are made to the software, regression testing plays a crucial role in supporting continuous integration and deployment. By automating regression tests, developers can quickly validate changes and ensure that the software remains in a deployable state.

Test Automation in Regression Testing

As regression test suites tend to grow with each found defect, manual execution of regression tests can become time-consuming and error-prone. This is where test automation comes in. By automating regression tests, developers can save time and effort, ensuring that tests are consistently executed and results are accurately recorded.

Change Impact Analysis in Regression Testing

In some cases, regression test suites can become extensive, making it impractical to execute all tests after every change. Change impact analysis helps in determining an appropriate subset of tests to be executed during regression testing. By analyzing the changes made to the software, the impact on various functionalities can be assessed, allowing developers to prioritize and select the most relevant tests.

Links

Code Examples

C#
[Test]
public void TestAddition()
{
    Calculator calculator = new Calculator();
    int result = calculator.Add(2, 3);
    Assert.AreEqual(5, result);
}

JavaScript
it('should return the sum of two numbers', () => {
    const calculator = new Calculator();
    const result = calculator.add(2, 3);
    expect(result).toEqual(5);
});

Python
def test_addition():
    calculator = Calculator()
    result = calculator.add(2, 3)
    assert result == 5

PHP
public function testAddition()
{
    $calculator = new Calculator();
    $result = $calculator->add(2, 3);
    $this->assertEquals(5, $result);
}

Conclusion