Shift-Left Approach
The Shift-Left Approach is a testing strategy that involves executing tests earlier in the software development life cycle. The principle of early testing is often referred to as "shift-left" because it shifts testing activities "to the left" in the development process.
Typically, shift-left suggests that testing should be performed as early as possible (for example, without waiting for the code to be implemented or for components to be integrated). However, it is important to note that this approach does not mean that testing performed in later stages of the process should be neglected. On the contrary, testing at all stages remains crucial to ensuring software quality.
Best Practices for Implementing Shift-Left
Reviewing specifications from a testing perspective: Conduct reviews of specifications (requirements, user stories, etc.) from a testing standpoint. These review activities often identify potential defects, such as ambiguities, incompleteness, and inconsistencies.
Writing test cases before the code: Develop test cases before the code is written. This allows the code to be developed to pass the defined tests, promoting test-driven development (TDD).
Using continuous integration (CI) and, better yet, continuous delivery (CD): These practices allow for rapid feedback and automated component testing to accompany the source code whenever it is submitted to the code repository. The use of CI/CD promotes shift-left by integrating automated tests at every stage of the development cycle (QA may request more efficient build management if it identifies that the process lacks a well-defined and executed CI/CD process).
Static code analysis: Perform static code analysis before dynamic testing or as part of an automated process. Static analysis helps identify defects without needing to execute the code.
Non-functional testing at the component test level: Conduct non-functional testing (such as performance, security, etc.) as early as possible, preferably at the component level. This is a form of shift-left, as traditionally these types of tests are performed in later stages of the process when the complete system and a representative testing environment are available. Traditionally, these tests are performed by the developer, but QA can monitor the evolution and execution of these tests.
Automation of testing processes and configuration of CI/CD pipelines: Although at many times the code to be tested may not be ready, QA can work on setting up testing environments, CI/CD pipelines, and test automation to ensure that as soon as the code is submitted, it is immediately validated against a set of tests.
Benefits and Challenges of the Shift-Left Approach
Adopting a shift-left approach may involve additional training, effort, and costs at the beginning of the process. However, this approach is expected to yield benefits such as savings in effort and costs during the later stages of development by identifying and correcting defects earlier, before they become more complex and expensive to fix. Some of the benefits that can be observed with the use of this approach include:
Cost Reduction and Rework: Defects found early in the development cycle are cheaper to fix. For example, a defect detected during the requirements phase can cost up to 100 times less to correct than if it were found in production. This reduces overall costs and avoids significant rework.
Faster Deliveries: With automated testing and continuous integration performed from the outset, the team can receive quick feedback and resolve issues immediately. This allows for more frequent and agile deliveries, reducing time-to-market and increasing competitiveness.
Improved Product Quality: Early testing allows critical issues, such as performance and security failures, to be identified before the system is complete. This results in more robust products that are less prone to failures in production, enhancing customer satisfaction and the company's reputation.
Risk Mitigation: Early identification of technical and business risks facilitates prioritization of critical testing and planning of mitigation strategies. With a proactive approach, the team avoids last-minute surprises that can impact schedules and budgets.
Focus on Collaboration and Alignment: By involving QA, developers, and stakeholders from the beginning, Shift-Left promotes more effective communication, aligning everyone on quality objectives and reducing misunderstandings. This results in a more cohesive team and more efficient development.