Shift left testing is an innovative approach to software testing that is gaining popularity in the software development industry. This approach involves moving testing activities to earlier stages in the development process, such as during the design phase or requirements gathering. By doing so, teams can catch defects earlier, improve quality, and reduce the cost of fixing defects later in the software development life cycle (SDLC).
This article will explore shift left testing benefits and provide practical tips for implementing this approach in your software development projects. Whether you are a software developer, project manager, quality assurance professional, or business analyst, this article will provide valuable insights into improving your software testing process and accelerating your time-to-market. We will also briefly introduce a tool that can help shift the testing phase left in case you are developing mobile applications.
Traditional Software Testing vs Shift Left Testing - Main Differences
As an integral part of SDLC, software testing is traditionally performed after the development stage. This approach can result in increased expenses and delay in the product release, as defects are discovered later in the process when they are more difficult and expensive to fix.
In contrast, when shifted left, testing is emphasized from the very beginning of the software development lifecycle. Catching defects earlier in the SDLC can significantly decrease fixing costs. This is because the cost of correcting a mistake in the early phase of software development can be significantly lower than when it is discovered later or even in production.
If we have a look at the graph below, we can see that the majority of bugs are introduced in the coding phase. In traditional testing strategies, most of them are identified closer to the release when the cost of their fixing is significantly higher than in the earlier stages.
We can see that allowing a bug to go unnoticed until the system testing phase can cost up to forty times more than catching it during coding and ten times more expensive than detecting it during unit testing. The cost becomes enormous if the bug goes undetected until the deployment stage.
In traditional testing strategies, bugs are detected in later stages of software development
On the other hand, with testing shifted left, the image looks quite different. The number of bugs introduced is still highest in the coding phase and the growth of the cost of them being fixed has the same trend. However, the orange curve indicating detection appears to be larger on the less expensive side, while smaller on the more expensive side, resulting in a considerable decrease in costs.
With the shift left testing approach, bugs are identified in earlier stages when fixing is less expensive
Here are some of the main differences between traditional testing and shift left testing.
| Traditional testing | Shift left testing |
|---|---|
| conducted after the software has been developed | conducted earlier in the development life cycle |
| a separate phase that comes after coding | integrated into the software development process |
| typically performed by a separate quality assurance team | developers perform testing along with QA specialists |
| can result in higher costs and delays in product release | can lower costs and accelerate product release |
| defects caught later when they are more difficult and expensive to fix | defects detected earlier when they are easier and cheaper to fix |
Shift Left Testing Benefits
Why teams should test earlier? There are numerous benefits that shift left testing offers to software development teams. Here are 7 main reasons to implement it:
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Early defect detection
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Improved software quality
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Faster time-to-market
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Reduced costs
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Improved collaboration
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Enhanced customer experience
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Better alignment with business goals
By catching defects early, shift left testing lowers the need for rework and improves the overall quality of the software. As a result, companies avoid unnecessary costs, and time-consuming bug fixes at later stages of SDLC bringing the product to market sooner. Early collaboration between developers, testers, and business analysts also enhances teamwork and productivity.
Additionally, the shift left approach leads to better customer satisfaction by ensuring that the software meets stakeholder requirements and delivers a better user experience. Finally, involving stakeholders early in the development life cycle ensures that the software aligns with business goals and objectives, increasing its value and impact.
How to Implement Shift Left Testing in Development Cycle - Best Practices
Implementing shift left testing can be a game-changer for your software development. Here are some strategies and tips for implementing shift left testing:
1. Involve developers in testing
In the shift left approach, developers take ownership of testing. Performing, for example, unit tests, they can catch defects earlier and improve the software delivery process. This can also help to bridge the gap between development and testing teams.
2. Use test automation
This strategy can help to decrease the time and effort required for testing. Automated tests can be run quickly and easily, and can help to catch defects at the very beginning.
3. Implement continuous integration and continuous testing
As a shift left strategy, with continuous integration, code changes are integrated into a shared repository frequently, which can help to identify defects quickly. Continuous testing involves running automated tests frequently to find bugs early.
4. Use static code analyzer
These tools can help to catch defects in the code before it is even run. They can identify potential bugs, security vulnerabilities, and other issues in an early development phase.
5. Conduct code reviews
By reviewing code before it is merged into the codebase, the development team can identify potential issues and improve the software quality.
6. Incorporate testing into the design phase
Testing should be incorporated into the design phase of the software development life cycle. This way, the development team can save time and effort later in the development.
7. Use test-driven development
This testing strategy involves writing tests before writing code. Test-driven development also encourages a more modular and structured approach to coding, which can make it easier to maintain and modify the codebase over time.
8. Use Behavior-driven development
This can be a valuable strategy for shifting testing to the left, as it helps to ensure that the behavior of the system is clearly defined and tested early in the development cycle.
Challenges and Considerations and How to Deal With Them
Testing earlier by implementing this approach can bring significant benefits, but it also comes with its own set of challenges and considerations. Here are some of them followed by ideas on how to overcome them.
1. Resistance to change
Some team members may resist the shift left approach because they are comfortable with the traditional testing approach. To overcome this, education and training sessions can be conducted to help team members understand the benefits of shift left testing.
2. Skill set requirements
Shifting testing to the left may require additional skills and expertise from team members, particularly in areas such as test automation, continuous integration, and continuous delivery. To address this, teams can invest in training programs to develop the required skill sets.
3. Infrastructure requirements
Shift left testing requires an infrastructure that supports continuous testing and integration. Teams may need to invest in new tools and technologies to support this. However, cloud-based solutions can help teams quickly set up and scale the required infrastructure.
4. Test environment limitations
Testing early can be challenging if the test environment is not yet available or incomplete. One way to address this is by using mock objects and stubs to simulate parts of the system that are not yet available.
5. Increased complexity
The shift left approach can increase the complexity of testing, particularly if multiple testing types and tools are involved. To overcome this, teams can adopt a structured testing approach that defines the testing types, tools, and processes involved.
6. Time and resource constraints
Implementing shift left testing can be time and resource-intensive. To address this, teams can prioritize the most critical and high-risk areas of the software to test early in the development life cycle. Additionally, adopting agile and DevOps practices can help teams to streamline testing and improve test automation.
By identifying and addressing these challenges and considerations, teams can successfully implement the shift left testing approach and reap the benefits it provides.
Use Case in Pharmaceutical Industry
Target goal: A leading retail pharmacy addressed EPAM to build and test a greenfield mobile app with an aggressive timeline while continuously evolving its design.
Steps that were taken: To improve shift-left testing, the team leveraged a private Mobitru instance with dedicated devices, support, and a mix of real iOS and Android devices to test compatibility at scale.
Result: The development team achieved improved manual testing speed by up to 50% and built up a CI/CD pipeline with Mobitru integrated with Azure DevOps and App Center. This allowed the team to leverage the services across 8 countries on 3 continents, utilizing a combination of 33 devices and OS versions for manual, automated, and production support teams.
Shift left testing was aided by Mobitru in this case and insured high-quality software was delivered to the customer on time and within the budget.
Mobitru
Cloud and On-Prem Mobile App Testing
Conclusion
Shift left testing is a paradigm shift in software development that prioritizes testing in the early stages of the SDLC. This testing strategy aims to catch defects as early as possible and reduce the overall cost of software development. By implementing shift left testing, teams can take advantage of a wide range of benefits, including improved software quality, accelerated product release process, and minimized development costs.
However, it's important to keep in mind that there are also challenges and considerations associated with this approach, such as the need for proper tooling (e.g. for test automation), cultural change, and skill set development. By understanding these challenges and implementing the right strategies and tools, teams can successfully shift their testing efforts to the left and deliver high-quality software faster and more efficiently.
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