In many organizations, software testing is often relegated to the end of the development cycle. This approach mirrors the outdated waterfall process, where testing seems to be an afterthought rather than an integral part of development. Even in iterative processes like Scrum, it’s common for testers to have little to do for much of the sprint, especially in the beginning, only to be overwhelmed with work towards the end. This practice leads to numerous issues being discovered late in the game—issues that should have been caught much earlier. 

Often, the root of these problems lies not in the code but in the requirements themselves. Unfortunately, the flaws of these requirements only come to light when the product is about to be deployed, as testing is, again, done towards the end of the development cycle. These necessitate massive changes that introduce delays and increased costs. In some cases, these late discoveries can lead to a complete re-evaluation of the project scope, requiring significant rework that could have been avoided. This reactive approach not only jeopardizes deadlines but also erodes stakeholder confidence in the development process.

As seen from the graph above, the cost of software defects increases drastically as the project matures into later stages. It is even comical to see the stark difference between the requirements and deployment/maintenance phases.

So how can we avoid high costs and additional work? The answer is relatively simple, and the key lies in testing, specifically, how it is placed in the development process. 

There is actually a growing movement within the industry that is meant to address such concerns of testing—that is, the “Shift Left” approach.

What is Shift Left?

Shift Left is a software development approach that advocates for moving testing and quality assurance activities earlier in the development process. The term comes from moving (or shifting) testing and quality assurance “left” on the project timeline—meaning earlier in the cycle. By integrating testing from the very beginning, alongside activities like requirements gathering, design, and coding, potential issues can be identified and addressed much sooner. Basically, this movement encourages testing throughout the development process and not just at the end of it, unlike the traditional waterfall approach. It mainly aims to catch potential issues before they become more costly and time-consuming to fix in the latter part of the development process.

Some Key Concepts of Shift Left:

1. Early Involvement of Testers:
   • Testers participate in discussions from the beginning, particularly during the requirements and design phases. This allows them to understand the system’s goals, identify potential risks, and provide input that can prevent defects before they occur.
2. Continuous Testing:
   • Rather than waiting until a specific testing phase, tests are performed continuously throughout the development process. Automated testing, code reviews, and other quality checks are integrated into daily workflows.
3. Collaboration Across Teams:
   • Shift Left emphasizes collaboration between developers, testers, business analysts, and stakeholders. This cross-functional approach ensures that everyone is aligned on requirements and expectations, reducing the chances of misunderstandings or incomplete specifications.
4. Feedback Loops:
   • The approach encourages frequent feedback loops. As features are developed, they are tested immediately, allowing teams to catch and fix issues quickly, preventing them from snowballing into larger problems.
5. Reducing Defect Costs:
   • The earlier a defect is found, the cheaper and easier it is to fix. Shift Left aims to catch defects at the source—during requirement definition, design, or early coding—when they are less costly to address.

Why Shift Left or testing throughout the development cycle matters? 

Based on its benefits, incorporating Shift Left testing in a project’s development cycle sounds like a good idea. However, it is easier said than done. This approach may introduce a drastic “shift” in culture, especially for those who are used to the traditional way of building software which makes it harder for many organizations to adopt Shift Left in their development process. But when you look at the overall impact of Shift Left or just applying testing throughout the development cycle, the gains would ultimately outweigh the drawbacks.

Furthermore, when testers are involved in the discussion of requirements, they often bring up scenarios that neither the business stakeholders nor the business analysts have considered. These insights can trigger valuable discussions, leading to a more thorough understanding and definition of the requirements and, ultimately, a better product. In fact, involving testers early can reveal flaws in the initial requirements that would have gone unnoticed until much later. This is mainly because of the perspective that testers have, which, arguably, even developers lack. Stuff like edge case scenarios and other curveball ideas, for the lack of a better word, come naturally to testers as they approach a product differently. 

I recall a particular discussion with our clients where three business managers quickly agreed on the specifics of the “End of Day” process for a particular branch. However, a tester raised some simple yet crucial questions: “What if a customer comes after the end-of-day process? Do we turn the customer away? Do we take the customer’s money? If so, how do we record the transaction?” Suddenly, all three managers had different answers, leading to a half-hour debate. This was a critical moment because it allowed the team to flesh out the requirement fully, scrutinizing every detail involved. As a result, the requirement was entirely reworked, and it became more straightforward and clear. Looking back, if we had just taken their initial agreement at face value and moved forward, we would have faced severe issues during the later stages or, worse, in production. Needless to say, the tester was definitely the hero.

Shift-Left’s distribution of cost defects

To put things in perspective, the graph you see above shows how incorporating testing at the earlier stages of the development process leads to the discovery of the majority of the defects at the earlier stages, which should be evident as testing is done during those phases. The key here is that those defects are discovered where the cost to fix them is relatively low.

This highlights the immense value of having testers involved in the early stages of development. By helping to define and clarify requirements and testing during the design and implementation phases, testers save a tremendous amount of time, effort, and rework, ultimately saving organizations significant amounts of money and time. More importantly, the quality of the product would inevitably skyrocket as bugs and other defects would already be scarce by the time the software is in production.

Conclusion

The message is clear: testing should not be an afterthought. By shifting left and involving testers in the requirements elicitation and analysis phases, organizations can avoid many of the pitfalls that lead to delays and cost overruns. The earlier you start testing, the smoother your development process will be, and the more successful your final product will be.