How to Move to Shift Left in Software Testing

Software Testing

Shift left is a term used in software development. It refers to a specific form of the lifecycle of software development.

There are many benefits to switching to a shift-left approach. The practice of shift left encourages collaboration between teams. It can help reduce inefficiencies and bottlenecks during software development that arise from defects in the code or miscommunication. 

Ready to shift left for yourself? Here’s how to practically implement shift left testing to boost the efficiency of your software development and lower QA costs.

What Does It Mean To Shift Left in Software Development?

The term “shift-left” refers to the traditional or Waterfall model of SDLC. In this development approach, testing and QA come at the end, or the right, of the cycle.

In the traditional model, SDLC goes through six stages. In order, they are: Requirement Analysis, Feasibility Study, Architectural Design, Software Development, Testing, and Deployment. Shift-left moves testing to earlier in the process (farther to the left).

Shift-left emphasizes finding and fixing bugs and defects as early as possible in development. Shift-left is designed to be flexible. It allows for continual testing and development through the process.

How Does Shift Left Testing Work?

Shift-left works best through the collaboration of an entire team, where everyone is responsible for a little bit of everything. Dedicated developers will be able to test code and dedicated testers will be able to write code.

This should be true to a small extent regardless of the development model. What makes shift left different is the level of communication between testers and developers. Having these two groups in constant contact has many benefits. Collaboration allows for inefficiencies and bottlenecks that are present in other models to be worked out before coding begins. 

In most cases, tests will be designed with automation in mind when shift-left is implemented. Through automation, code can be tested at any time by anyone.

Automation is harder to do when the code being tested does not have unified elements. Collaboration between testers and developers encourages code to be written in a way to enable easy testing. Each team member will understand what the others are working on and how their work fits the bigger picture. 

What Are the Tools for Shift-Left?

Beyond the typical scope of tools available during the development process, there are also tools specifically designed for a shift-left approach. 

Most of these tools feature the ability to automate testing and integrate with other development tools. Some of the highest-rated shift-left tools are:

Which one works best will depend on the software, the language, and other tools used. There is no single tool necessary to adopt shift-left. Use what is available to you and work off of that.

Types of Shift Left Testing

Shift left testing is not a new concept and has existed in the software development sphere for years. Since its inception, several versions of shift-left have popped up. The most current shift-left models change the original to fit changes in the field. The four different types of shift-left are:

  • Traditional
  • Incremental
  • Agile/DevOps
  • Model-Based


The traditional model of shift-left focuses less on system-level testing and more on unit and integration testing. Testing shifts left slightly from the Waterfall form of the development cycle.

Testing in traditional shift-left is done on a smaller and more frequent scale. If done correctly, this will result in fewer code defects integrated on the system level. The main benefit of preventing bugs from reaching the system level is the lowered cost of fixing them. They can be detected and eliminated before there are too many negative results.

This form of shift-left offers a bit more flexibility than the Waterfall approach. The units used can be changed and modified before being integrated into the larger project. They can be reworked if requirements change before the end of the development cycle.


The incremental shift-left is typically used during the development of large and complex software. This model breaks down the phases of development into increments or smaller individual pieces. 

Working with smaller pieces of code allows for quick and thorough testing. The design of incremental shift-left features each increment building off of the last. The testing of each increment shifts left as needed within the development process.

The incremental approach to shift-left is even more flexible to change than the traditional model. Individual portions of code are open to modification to fit new requirements. Subsequent increments built later will need to be adapted, but will require less work overall.

An incremental shift-left works well with larger organizations that deal with complicated projects.


The Agile or DevOps shift left model is designed for numerous and quick-paced projects. The development process gets broken down to match the timeline of each project. It can then be implemented into a system or software.

The shift-left aspect of this model occurs as the testing and development of projects happens as a continual sequence, one running directly into the next. The testing of one portion of the project occurs before the planning of the next part is finished.

This form of shift-left works well when work needs to get completed fast and continually. 


Model-based shift-left has several fundamental differences from the other types of shift-left. Unlike the other forms of shift left, model-based is not code-centric. Meaning testing begins before code gets written. 

Model-based shift-left introduces testing into every phase or step of the development cycle. The model-based approach includes the designing of requirements or architecture. Being able to test architecture before software development means you can catch more bugs and save both time and money, which makes model-based testing one of the most effective means of shifting-left.

The model-based form of shift left focuses on ensuring every phase of development is designed with testability in mind. This emphasis helps prevent issues from arising down the line and costing more to fix in the moment.

Model-based shift-left is the most flexible of every shift-left approach, adaptable to the needs of any project.

How to Move To Shift-Left Testing

Once you have decided to move to a shift-left, it is important to communicate this to the developers and testers on your team. Discuss your plan with them and get feedback on how to best integrate the new approach with your team and their existing work methods. 

Take time to explain why you are moving to shift left and the benefits this change will bring for them. Talk about your expectations of the change, but remain open to the suggestion of your team. Be understanding of how their workloads will change and build realistic standards for them to work off of. 

Take things slowly. Moving to shift-left can require significant changes to the culture of a workplace and the way things are done. Make sure that everyone on the team is on the same page throughout the change. Give your support as changes are implemented for an easier transition.

Planning and Determining Resources

One of the biggest downfalls of traditional software development models is the lack of resource planning for testing.

Having testing at the end of the development cycle often prevents the proper allocation of resources. By the time testing is finished, there may not be enough time to properly fix any bugs that are found. This will result in either a delay in shipping or sending the software out with bugs, which will be expensive to fix at later stages.

At the beginning of the development cycle, plan out how testing will be integrated throughout the project and how resources will be distributed. Create a rough schedule for your team to follow and highlight the most important tasks they need to focus on.

Involving QA Early and Collaboration

Getting the people responsible for testing involved early in the project is a must for shift-left. Having a representative of QA present in meetings and project discussions will help to  open communication between testers and developers. 

Testers and developers will be able to give each other feedback, reducing delays caused by miscommunication or lack of understanding. Encourage collaboration between groups to the point where resources and ideas are shared as needed. This can save time and reduce inefficiencies.

Design Code With Testability in Mind

Designing code with testability in mind can significantly reduce the overall time required for testing. Code that is designed to work with testing in mind will allow for more automation to be implemented overall. 

Testers will need to spend less time working with the code to get it to work with necessary testing. This lets testers spend more time working to find bugs in the code. The sooner and more precisely bugs are found, the more time developers have to implement fixes. 


Shift-left has many benefits when used in software development. It boosts the speed and efficiency of the development cycle when working through the testing phases. Overall inefficiencies in development are reduced, and the typical bottlenecks are avoided through proper resource management.

Any defects in the developed code are recognized quickly and fixed promptly. Because of this, shift-left follows many of the principles of failing fast

Defects, bugs, and failures in the code are present in every project. Recognizing this and building a system around that fact is what allows for innovation. Shift-left benefits every member of a development team when implemented correctly.

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