Software testing is ever-evolving with growing technologies and approaches which strive to provide high-quality software faster than ever. In traditional software development models like the Waterfall model testing is sequential and is done only towards the end of the development lifecycle or to the extreme right side of the pipeline. This approach often results in the accumulation of defects with significant rework, leading to increased costs and project delays. Let's explore how shift-left testing can help to overcome this situation.
What is Shift Left testing?
Shift-left testing is an approach that involves moving testing activities to earlier stages of the software development lifecycle (SDLC) to catch defects and risks early. With a shift-left approach, testing takes place earlier in the development lifecycle, and at all stages making sure that quality is considered from an early point in the development process, reducing costs and risk. The main objective behind shift-left testing lies in the concept of defect prevention rather than just defect detection.
Why do we need this approach?
In the traditional development process testing is done only later in the cycle which is also known as Shift-right testing. A few of the drawbacks of testing late in the cycle are as follows
· Higher costs
· Critical bugs in deployment can delay the delivery of the product
· Poor production quality
Shift- left approach allows us to Test early, test often, test faster, and automate. Overall, this approach emphasizes the early involvement of testers in discussions and idea collaboration at every stage.
Types of Shift Left Testing Methods
There are four basic methods to implement shift testing earlier in the lifecycle.
1. Traditional Shift Left Testing
The traditional approach aligns with the V-model which is an extension of the waterfall model. The V- model also known as the verification and validation model has a testing phase with each phase of development. The traditional shift left testing also focuses on unit testing and integration testing. The emphasis is given to system-level and acceptance testing.
2. Incremental Shift Left Testing
The incremental shift-left testing approach can be used in the development of large and complex software systems. As large complex development projects are difficult to manage it is often broken down into smaller components that build upon each other incrementally. With each incremental delivery, development, and testing are shifted to the left.
3. Agile/DevOps Shift Left Testing
Agile or DevOps development emphasizes continuous testing through many short-duration sprints. As we have multiple sprints throughout the development it allows you to test the project as it builds on itself.
4. Model-Based Shift Left Testing
Model-based shift left testing implements the testing of executable requirements, architecture, and design models and aims to reduce errors introduced during this phase.
How to Implement Shift Left Testing in Agile?
The API-first approach prioritizes APIs at the beginning of the SDLC where the design of the application starts with an API before any code is written
Active involvement of testers in every stage
Testers should take ownership of the quality and release of the product by documenting, adding evidence, creating test cases, test closure reports, regression packages, automated tests, and monitoring CI/CD pipelines.
Static testing is a process of verifying and validating the requirements, logic errors, or design documents before executing the code. Static testing checks a codebase before it is built.
Involving developers in testing
Encouraging developers to perform unit tests on individual modules before pushing them to the main branch will create a cleaner code. Unit tests verify the functionality of a specific module within a larger application.
The risk-based analysis is carried out to determine the impact and likelihood of failure for each test scenario. This approach is used for functional, non-functional, and regression types of testing. Also, security testing is planned early in the cycle.
Benefits of Shift left testing:
Early defect detection: Testing early helps in finding the bugs early
Accelerated release cycle: As we are detecting the bugs early overall product quality is improved before reaching the final release. The process is streamlined hence enabling quicker releases
Reduced development and testing costs: The time and effort taken to resolve the bug found in development is way lesser compared to a bug found in production. Also, it reduces the amount of rework
Improved collaboration and communication: Shift-left testing promotes better collaboration between development and testing teams. It helps in open communication, shared understanding, and increased alignment between teams. This collaborative approach enhances the overall efficiency of the development process and facilitates the exchange of valuable insights and feedback.
More focus on automation: Incorporating automation speeds up the testing process and will ensure quick feedback
Transition Plan: Shifting testing activities earlier in the SDLC may require additional resources and effort. The organizations need to develop a clear plan that outlines the changes required for both the QA and development teams. Additionally, involving testers in the early stages may increase project timelines initially. However, the long-term benefits of reduced costs and improved quality outweigh these initial investments.
Test Planning: Test planning shifts to a continuous collaborative process. Both QA and development teams must familiarize themselves with this new approach and establish open lines of communication for continuous feedback.
Project Management: In some cases, the shift-left approach may slow down the development process. Organizations must strike a balance between testing and development activities to ensure that both aspects progress smoothly. Effective coordination and collaboration between development and testing teams are crucial in maintaining a productive and efficient workflow.
Conclusion: The Shift-left testing approach requires a change in mindset and strategy. Hence it is important to adopt Agile and DevOps methodologies that enable continuous integration, delivery, and testing. It works well with agile practices like BDD or TDD and helps in continuous testing.