Software development is often described as a left-to-right timeline: you start with an idea, move through design and prototyping, then build production code. In many teams, testing still happens only at the very end of this timeline. If a critical bug slips through late testing, it can end up in customers’ hands — forcing expensive fixes and risking public reputational damage.
By introducing testing earlier in the software development life cycle, any problems that are found will be cheaper to fix. Addressing a problem in the user interface is less time-consuming if it’s identified at the design stage, rather than having to undo hours of development work when the issue is not found until the production code has gone through several iterations.
The idea of ‘shift-left’ testing is that moving the test processes to the left of this axis can save time, money and embarrassment for a software company. Here I will explain how teams can embrace the shift-left philosophy and why it’s so important for building effective software applications.
Why ‘shift-left’ matters for modern testing
Shift-left testing describes the practice of moving testing activities earlier in the software development lifecycle, instead of waiting until the final stages. While often associated with agile methods, the roots of shift-left thinking go back much further — for example, Barry Boehm’s V-model from late 1970s emphasized verifying and validating requirements and design early to avoid costly rework later.
That’s why the maxim ‘test early and often’ is repeated so much in software teams. In reality, testing is still frequently done too late and too little, because resources are always limited. Ideally, you would validate after every stage, but that isn’t always realistic. The key point is to test as early as possible, because the earlier you catch defects, the cheaper and easier they are to fix.
However, companies will need to be certain that when they make changes to the codebase that they don’t introduce bugs that break something that was previously working well. Regression testing is the process of making sure that everything that worked before still works after new features are added or updates are made.
Regression testing is a necessary part of any serious software development process, whether agile or not. It helps ensure that previously working functionality still works after new updates. If you need a reminder of just how critical it is, think back to the CrowdStrike update in July 2024 that impacted millions of Windows systems worldwide with considerable disruption to businesses and services.
How to adopt the shift-left approach
To adopt shift-left effectively, companies should first analyze where problems tend to surface today. Then they can move targeted parts of their testing earlier, depending on their challenges. For instance, if customers struggle after deployment, shift more testing before release. If final testing is delaying deployment, shift testing into the development phase. If too much rework happens after development, move usability or UI testing into the prototype stage.
Shift-left isn’t one-size-fits-all: it’s about strategically moving the right tests earlier in the cycle to prevent waste and defects. This starts with developers writing comprehensive unit and integration tests, complemented by automated API tests and static code analysis running in the CI/CD pipeline.
But for shift-left testing to be effective, the testing itself has to be well-organised and managed.
Test case creation is one of the most important facets of software testing. This requires Quality Assurance (QA) teams to assess the most appropriate tests for the functionalities of the software, and to decide at which stage these tests should be run. For example, performance testing under heavy load or cybersecurity checks aren’t feasible to run at the design stage, so there’s a limit to how far to the left these can be shifted.
In the case of test case creation, specialist expertise is required. Well-written test cases reduce the risk of bugs and ensure the end product is of a high quality. They provide testers with detailed instructions for running tests and list expected outcomes, ensuring the integrity and reliability of the testing process.
The number of potential test cases will rise exponentially with the complexity of the application, so experienced QA teams will be able to accurately judge which tests are necessary to run and which aren’t, ensuring the process is efficient.
Testing must be well-organised
Once the test cases have been written and there’s an agreement about when they should be carried out – and when regression testing is required – teams must also set out clear roles so everyone knows who is responsible for testing what.
Ideally, testing should involve people who can stay objective — whether that’s QA engineers, SDETs, or even other developers — since testing one’s own code can be challenging from a psychological and impartiality perspective.
While there can be an element of automation in the process of testing – and even in test case creation – there must always be human oversight, with clear accountability.
And it’s also important that the lines of communication between the QA teams and developers are strong. Many software companies rely on spreadsheets, emails and even Post-It notes; these do not make for efficient workflows and could cause more problems than they solve. If someone misses an email containing important information about a bug that needs to be fixed might go astray, or if someone is working in the wrong version of an Excel file, tests might be unnecessarily duplicated or missed altogether.
That’s why it’s essential to use dedicated test management tools to ensure the testing process is as streamlined as possible. Managers will be able to get a comprehensive view of progress, test results will be fed back to the right people at the right time, keeping everyone on track and working together.
Effective test management is vital for the shift-left approach to work
The shift-left approach improves efficiency and quality by integrating testing into every stage of development. But as testing becomes a distributed activity — with developers running automated unit tests, pipelines executing integration checks, and QA specialists performing exploratory sessions — it generates signals from dozens of disconnected sources. Without a central hub, this creates noise, not clarity.
This is where a modern test management approach, enabled by dedicated tools, becomes the backbone of quality. It provides the single source of truth that aggregates results from both automated pipelines and manual testing efforts. This ensures that a passed unit test isn't mistaken for full feature validation and that critical insights from human testers are tracked with the same rigor as automated checks. ‘Test early and often’ is a powerful mantra, but it’s only truly effective when the entire quality story can be seen, managed, and understood from a single, cohesive viewpoint.
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