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Shift Left Testing in Agile Development

Shift Left Testing in Agile Development


In an Agile world, software and IT teams are under constant pressure to move faster. Typically, this means decreasing the relative length of delivery time while continuing to improve quality on each successive release. At the same time, there’s always pressure to minimize testing costs.

under increasing pressure to maintain quality while increasing the velocity of delivery

The software development process has been shifting left due to the growing challenge of developing and delivering software releases faster and faster. Agile methodologies and new roles, such as Dev Ops, have been created as a result of this shift.

exists to enable the business to do business! That mission is achieved through the design, delivery and operation of the innovative systems and solutions that each business requires. The challenge CIOs face is keeping up with exponentially increasing demands and the business expectation to deliver solutions fast, at a lower cost and with higher quality.

So what do you mean by Shift Left? What is Meant by Shift-Left Testing?

One of the most widely used software development models was the ‘Waterfall Model’. The major drawback with the ‘Waterfall Model’ was that the testing activity was not performed at every stage; hence bugs (major/minor) were unearthed only after the ‘product development’ was complete.

Shift-left testing refers to the integration of testing activities with development, beginning sooner in the development cycle, rather than later as in traditional software development environments like waterfall.

More than 10 years ago the typical development and QA cycle was organized around the waterfall model. Developers would work on a base-level and when it was done, it was passed to QA. QA would test that base-level and feed the results back to the development team to fix. Then the cycle would be repeated as necessary.

There are a few reasons for this cost escalation:

  • The time and effort it takes to track down the problem. The more complex the test case is, the more difficult it is to figure out which part of it is the real troublemaker
  • The challenge of reproducing defects on a developer’s desktop as dependent systems like databases or third-party APIs are brought in (it’s common for organizations to experience a lag of several weeks between defect detection and defect remediation in these situations)
  • The impact of the change that is needed to fix a defect. If it’s a simple bug, it doesn’t matter so much, but if you have it in many places, you’ve used the wrong framework, or you’ve built code that isn’t scalable enough for the expected load or that can’t be secured, it’s a larger problem

Since it is easier and cheaper to fix bugs detected earlier in the process, new strategies of shifting tests earlier in the software development lifecycle were introduced to help identify issues as early as possible.

Shift Left is a practice intended to find and prevent defects early in the software delivery process. The idea is to improve quality by moving tasks to the left as early in the lifecycle as possible. Shift Left testing means testing earlier in the software development process.

The “shift left” testing movement is about pushing testing toward the early stages of software development. By testing early and often, a project can reduce the number of bugs and increase the quality of the code. The goal is to not find any critical bugs during the deployment phase that require code patching.

Shift left testing approach is considered one of the most popular approaches to software testing and system testing.

It’s hard to pinpoint exactly, but roughly 85% of the code defects are introduced during the coding phase.

the cost of finding a bug also varies at which stage of the software development cycle the bug pops up. Numbers may vary, but on average, the cost is five to 10 times higher when finding a bug during system testing or even higher during the actual release of a product

As a result, there is more time left for feature development, attaining customer feedback and responding to it.

The Role of QA

For testers to be successful today, they have to not only be great at testing, but also be engineers of the Agile testing process by collaborating with development and operations while analyzing quality during every stage of development:

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This means working together with development and operations and analyzing quality during every stage of development as shown in the graphic below.

For example, testers have to jump in and take a more proactive role even before development starts by being present during the gathering of requirements.

Other activities include:

• Testers helping developers implement unit testing

• Planning, creating, and automating integration test cases

• Planning, creating, and employing virtualized services at every stage and component level

• Gathering, prioritizing, and processing feedback

Why Shift Left?

In the traditional software development model, requirements are kept on the left side of the plan, and the delivery and testing requirements on the right. The problem is that these practices can’t handle changing expectations and requirements, resulting in negative outcomes for the business such as:

Increased costs

Increased time to market

Unexpected errors

Shift left your open source compliance and security checks

Due to increased usage of open-source frameworks or projects in applications that they have developed or delivered in the past 12 months.This shows that open source is practically ubiquitous.

There are two primary aspects you need to shift left in regards to open source:

  • License compliance – ensure all your open source components are licensed properly (no license, means it is merely a public code but the author still hold the copyrights for it and you cannot use it) and that you can comply with the open source license.
  • Security vulnerability – unlike proprietary code, with open source you have the benefit of a large, active, capable and committed community identifying and fixing issues.

The Shift left approach emphasizes the need for developers to concentrate on quality from their earliest stage of a software build, rather than waiting for errors and bugs to be found late in the SDLC. Shifting left enables product teams perform daily tasks like:


Providing feedback

Reviewing changes and progress

Applying the Shift-Left Approach

So, how do you shift left? For the sake of brevity, the shift left testing approach breaks down into two main activities

How to Get Started With Shift Left Testing

  • Coding Standards
  • Testing in Early Stages of Development
  • Leveraging service virtualization to enable continuous testing.
  • Embrace Test Automation
  • Use test automation technology to increase testing bandwidth.
  • Focus tests on areas within the application architecture that provide the most quality coverage, while minimizing test maintenance.
  • Combine coding and testing into a single activity by using “shift left” best practices.
  • Implement continuous integration (CI) and automated testing by adopting best practices and using CI and software test automation technology.
  • Devise a shift-left testing strategy with the help of the test automation pyramid and your teams’ input.

How to move to Shift Left

There are some key strategies that will help you shift left with your software testing:

Demand planning

Test analysts will engage with business and operational stakeholders, providing a forward view of demand. Having this view enables you to—ahead of time—plan and finalize:

  • The budget
  • Resourcing
  • Test strategies

Demand planning is an integral part of the shift left approach and provides a starting point for all other activities in the test lifecycle.

Static testing

Static testing is carried out in the early cycles of the project, and includes validation of requirements and design. The purpose of static testing is to find defects early in the life cycle that could prove to be very expensive to remove in the later phases of the project.

Use appropriate checklists to verify and validate requirements and design. Log defects into a defect management tool.

Unified test strategy

This is an overall, high level strategy for testing end-to-end—from unit testing through user acceptance testing (UAT), operational readiness testing (ORT), and post-deployment testing. The strategy will cover all phases of quality control, defining clear responsibilities.

A unified test strategy allows you to analyze dependencies on environments, stubs, automation, and test data—ensuring that the respective teams can fulfill the needs.

Risk-based analysis

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.

Once the test cases are established, decide the priority for the test cases based on the finished analysis. Discuss the impact of failure with the business analyst or designer. Determine the likelihood of failure from the development team.

API Testing

API are the backbone for any product and usually independent and ready for testing API service testing with different environment for stability check Test before UI is ready Code Review – Use of Static Analysis Tools

Wireframes Testing

Identification of missing requirements in the early stage of the product development Helping customers with more inputs in the initial phase of requirements Usability Testing Testing in terms of business requirements at the early stage of project kick off Check the skeleton in the initial phase of development and post deployment via BDD

Best approaches for Shift Left

  • Test-driven development requires you to first write the tests for the piece of code you want to develop. Therefore, you can immediately verify the validity of your code.
  • use of static analysis tools. A static analysis tool helps to identify problems with parameter types or incorrect usage of interfaces.
  • behavior-driven development (BDD) can accelerate the shift left movement. BDD defines a common design language that can be understood by all stakeholders, such as product owners, testing engineers, and developers. Therefore, it enables all involved stakeholders to simultaneously work on the same product feature, accelerating the team’s agility. (ISTQB)TBD

Benefits of Shift Left Testing

  • Find bugs early on in the software development life cycle
  • Reduce the cost of solving bugs by detecting them early on
  • Gain a higher-quality product as the code contains fewer patches and code fixes
  • Have fewer chances that the product overshoots the estimated timeline
  • Provide higher customer satisfaction as the code is stable and delivered within the budget
  • Maintain higher-quality codebase
  • 76 % Improved application quality
  • 69 % Fewer bugs discovered in production
  • 68 % Fewer bugs discovered by QA
  • 53 % Increased application performance
  • 52 % Faster time to deployment
  • By integrating testing early in the cycle, teams can find and fix defects faster saving a lot of time and cost
  • Shift-left enables teams to fail fast and fail forward
  • Enhances developer’s efficiency and code stability as the developers write code with testability
  • Shift-left testing promotes test automation practices allowing developers to test their code through Continuous Integration quickly
  • Helps build a high-quality product and launch it within the estimated timeline
  • Ability to achieve code stability translates in improved customer satisfaction
  • By discovering defects earlier during the requirements phase, teams can speed up project delivery by 15-35%.
  • A well-organized process provides the most efficient and effective way of accomplishing work on-time and with fewer surprises. Quality Assurance is focused on developing, documenting these processes, and then measuring and continuously improving them.
  • Increasing test coverage by running more tests in the same amount of time
  • Freeing up time for testers to focus on more challenging and rewarding tasks
  • Reducing human error
  • Monitoring performance over time
  • Code quality checks
  • Built-in security checks
  • Reducing issues in production (that users will face)
  • Early detection of bugs & faster time to market
  • Engage everyone in the team, more collaboration for any team working in Agile development
  • Continuous feedback to help product is best in all quality standards in cutting edge competition
  • Reducing testing time, efforts & surely the cost Better resource management
  • Early detection: Find bugs early and fix them before they become a problem in production
  • Cost savings: Time and resources can be quickly used up. Shift-left testing helps reduce that problem and saves you money.
  • Reliable testing: Increase your testing reliability by using the shift-left testing procedures
  • Teamwork makes the dream work: Create a sense of unity amongst your developers and testers by keeping differences between them from creating a bottleneck.
  • Fast delivery: Deliver your product to the market faster.
  • Development pipeline: Shift-left testing helps to perform testing as soon in the development pipeline as you can achieve.

Lower costs

Rework costs for defects that slip into production can cost companies multi-millions of dollars per year. At $1800 or more in direct costs (not to mention the business impact of defects) to fix a single production defect, improving the defect removal efficiency (DRE) rate by just 8% can result in substantial cost savings for an enterprise.

Reduced operational costs due to fewer production incidents for higher availability and reliability can result in a 2% reduction in operational expense.

Higher business process quality & glitch-free execution

Whether you call them “incidents” or “production defects” or “glitches,” early defect resolution will ensure that there are fewer of them, and that every business process functions as it should out-of-the-gate at deployment.

Early defect discovery in the requirements phase also ensures that your team fully understands business requirements prior to development. It’s critical to eliminate all ambiguity from requirements so that your team delivers on the needed features and functionality.

Ability to use test automation tools. As we want to test early and often, test automation helps you accomplish this goal. We don’t want to overload our testing team with manually testing every new feature the development team introduces. Therefore, a test automation tool can give quicker feedback regarding the stability of the new code. Furthermore, a test automation tool helps your team shift left. Your team can write tests faster and it becomes easier to maintain them using a test automation tool. For example, Testim offers a solution to codelessly record tests via UI interactions.

Benefits of a shift left approach

There are several benefits that can be obtained by adopting a shift left strategy. Here are some of the most important:


Shifting left gives a greater ability to automate testing. Test automation provides some critical benefits:

Much fewer human errors

Increased test coverage (multiple tests can be conducted at the same time)

Ability for testers to focus on more interesting and fulfilling tasks

Fewer production issues

Increased delivery speed

Earlier means faster. When you find defects earlier in the production cycle, you can also fix them a lot faster. As a result:

The time between releases can reduce significantly.

The quality of software improves.

Increased satisfaction

Faster delivery of software with less defects is a major benefit of the shift-left approach.

If nothing else convinces you that this is a good move, then the smiles on the faces of your business partners should be all you need.


Risk Of Bottlenecks

Yes, agile and shift-left aim to eliminate testing as a bottleneck, but it is true that agile teams can find themselves stuck waiting in a queue once all of the pieces come together in the performance and user acceptance testing phases, due to the complexity of environments and composite applications. One way to overcome this is to to utilize service virtualization. Service virtualization emulates the behavior of essential components that will be present in production, enabling integration tests to take place much earlier in development. This is how you can eliminate that key bottleneck, while also benefiting from eliminating errors earlier on. Along with service virtualization, there are several tools to setup automated systems and CI such as Jenkins.

Wrapping Up

With Agile being the norm, shift-left testing is a key enabler for increasing quality and efficiency, reducing costs and risks, and staying competitive. In shift-left testing, everyone becomes a quality engineer and the responsibility for producing high-quality software is equally shared among the team.

This ultimately results in a better product, shipped even faster.

Agile and Shift-Left

The agile methodology includes testing as an integral part of the shorter development cycle. Therefore, shift left testing fits nicely into the agile idea. The testing engineer has to perform testing after each code increment—often referred to as a two-week sprint.

What Is the Idea of Shifting Left?

The shift left movement is about moving the testing phase earlier in the software development life cycle—shifting left. We want to avoid approaches where testing is only carried out at the end of the software development life cycle. With shifting left, we introduce testing in the early stages of software development.

Is Shift Left Testing the Way Forward?

This entirely depends on your organization. In theory, every organization can move toward shift left testing. You can start small by introducing coding standards or embracing a static analysis tool.

Shift-left testing advocates shared responsibility for building a high-quality software. Shift-left testing is the next big thing because it promotes a culture change in the organization moving from a traditional quality assurance to the new age quality engineering practices.

Shift-left streamlines the entire development and testing processes, feedback loops, thereby leading to an improved product quality. This brings about a positive culture change, stimulating an environment of conducive growth for everyone in the organization.

Applying shift-left or shift-right testing to increase efficiency and conserve resources is fine and dandy, but for the ultimate effect, you need to consider using continuous testing by bringing together development, DevOps, and QA, implement automated testing strategies, and enjoy the benefits of releasing stable apps.

When you shift left by leveraging modern software testing technologies, you can achieve software that is safe, reliable, and secure. By shifting testing left, you can reduce the cost of testing by finding bugs earlier, when it's cheaper, while also reducing the number of bugs you put into the code in the first place.

Testers will find themselves delegating some of their work to developers and assigning them more testing activities. In mature teams, the testers become “coaches,” training developers on how to write better code, avoid bugs, and own unit testing. The advantage of this is that the tester who used to be busy, bogged down by writing test cases, now has time to delve deeper into the product, working on business cases, penetration testing, performance testing, implementing smarter testing solutions that use artificial intelligence like, and so on. This sharing of the responsibility over testing leads to a higher level of achieved quality, as more of the bases get covered, quicker!

Overall, shift-left testing is all about incorporating testing earlier and earlier in the development process. In other words, it is the first half of the maxim "Test early and often." However, making the jump to shift-left testing is not an easy task, and if you are not aware of the barriers to it, you will head for disaster. So make sure you have a solid plan in place before incorporating this testing procedure into your organization.

© 2022 Darko Stojanowski

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