A Study in Favour of Shift-Left Testing
Tags: softwaredevelopment, softwareengineering, testing, devops
Published: 2024-03-16 19:50:17

The technology industry is evolving rapidly, necessitating agility and efficiency in development processes. Agile and Kanban practices have become instrumental in maintaining quality while accelerating delivery. A key paradigm shift in testing and QA approaches is the adoption of “Shift-Left” testing. This article explores the significance of Shift-Left testing, its divergence from traditional methods, the associated benefits and common applications.

Difference with Traditional Testing: In traditional testing, the testing phase is positioned towards the “Right” of the software development life cycle (SDLC). This means that requirement understanding, test case creation, execution, and defect detection occur after development is complete. This approach poses risks, such as delays and missed project timelines due to late bug detection and increased rework. To address these issues, the Shift-Left approach moves many testing steps to earlier phases of the project. It promotes collaboration between developers and testers, fostering shared responsibility for quality.

How Shift-Left Helps:

Early Bug Detection: By testing early, Shift-Left testing catches defects in their early stages, reducing the risk of critical issues going unnoticed. This minimizes the cost and effort required for defect fixing, avoiding setbacks.

Improved Communication and Collaboration: Continuous feedback from testers enhances code quality and increases efficiency. Testers gain a clear understanding of requirements from the beginning, resulting in better collaboration.

Faster Time to Market: Shift-Left testing accelerates the development cycle by reducing rework, optimizing test cycles, and streamlining defect resolution. This enables organizations to gain a competitive edge by delivering software solutions faster.

Test Driven Development (TDD): The Shift-Left approach aligns well with Agile continuous testing and TDD methodologies. Features are tested from the initial draft code and continuously throughout the development process. By the time formal testing begins, a significant portion of the testing steps has already been completed, reducing inefficiencies.

In a Shift-Left approach, testing activities are not delayed until a dedicated testing phase. Instead, they occur concurrently with development. The following steps exemplify this approach:

Requirements understanding from testers’ perspective

Test planning

Test design

Test environment setup

Code quality reviews

Partial test execution

Early defect identification and management

Types of Testing In-Scope

While not all testing types can be executed before development is complete, the following can be shifted at least partially to the left.

Unit Testing: In Scope. Developers conduct unit testing during development once logical functionalities are complete.

Integration Testing: In Scope. Testers can test the integration between various modules early and continuously.

Regression Testing: In Scope. If regression test cases are automated, they can be executed during development, providing early feedback. Manual testing may have limited success in shifting regression testing to the left.

Performance Testing: Partially in-scope. Proper performance testing requires complete deployment, making early results less accurate and beneficial.

System Testing: Partially in-scope. By definition, system testing involves testing the software as a whole and is typically executed after development completion. However, preparatory steps, such as test creation, can occur earlier.

Security Testing: Partially in-scope. Similar to performance testing, comprehensive security testing is advisable after development completion.

Implementing the Shift-Left approach requires a cultural shift and additional training for testers. Despite the challenges, it offers significant advantages to Agile teams and organizations requiring rapid development and testing. While the concept of Shift-Left testing has existed for some time, it has gained additional traction in recent years, helping organizations stay competitive in the ever-evolving software development landscape.