What Is Shift-left Testing?

Shift-left testing is a software testing technique where testing is performed before the actual software development starts, specifically during the design and requirement stage of the software lifecycle. This helps find and fix issues early and builds teamwork between developers and QA teams. It highlights early participation, ongoing testing, and using automation tools. This method captures and fixes problems sooner, saving money, speeding up product releases, and overall improving software quality.

Why is it called shift-left?

The term shift-left means doing the testing earlier in the development cycle, starting from when you’re figuring out what the software needs to do and designing it. Before this, traditional testing used to happen more at the end of making the software, in a phase called testing or quality assurance. But now, with the help of agile techniques, there’s been a change in how we approach testing, pushing it earlier in the development timeline.

Why is shift-left testing important?

Early issue identification

Shift-left testing is essential for finding issues early in software development. By testing earlier in the stages of development, problems are spotted and fixed right from the start. This bold method reduces the chance of big issues in the development cycle, which helps to save time and effort in fixing bugs.

Cost-efficiency

Shift-left testing is also essential because it helps save money in the software development process. Finding and fixing problems early is cheaper than waiting until last. Spending on testing at the start is very beneficial because it stops the critical issues from worsening, reduces the need for big fixes, and reduces the overall cost of making software.

Faster time-to-market

Shift-left testing is necessary for making software development faster and bringing products to market quickly. The process becomes smoother by including testing early and consistently throughout the development cycle. This helps find and fix problems faster so teams can expedite the delivery of good-quality software to end users or clients. Speeding up development makes it easier for organizations to respond to market needs and be more flexible.

Improved collaboration

Shift-left testing promotes teamwork between developers and QA teams in the development process. This collaboration improves communication, understanding, and a joint commitment to software quality. By getting involved early and providing ongoing feedback, teams can collaborate smoothly for a more effective and suitable development process.

How to perform shift-left testing

Developers testing their code

When developers conduct unit testing before adding it to the main branch, the resulting merged code is cleaner and less likely to have errors. Splitting the code into smaller parts or units makes it easier to test everything properly. When developers test their code, it helps them take responsibility for it and be more proactive in finding and fixing problems early in the development process.

Introducing testers to coding

A cross-functional approach is vital for the best results in an Agile and DevOps environment. This means getting developers to know some testing and teaching testers some coding basics. They don’t need to be experts in each other’s areas, but this approach lets developers do initial tests, and testers can understand and modify simple code. It improves code reviews and makes the testers helpful team members in the development process.

Early inclusion of testers

To reach its full potential, testers must take part early in the development process for shift-left testing to be effective. Being part of key sessions helps them understand the basics to create better tests later. This early teamwork ensures that developers know about possible issues and can work to prevent them.

Coding with testability in mind

In shift-left testing, thinking about testability while writing code is essential. Developers should ask, “How can I make testing easier?”. This can be done using hooks or unique identifiers to simplify testing. Testability also alerts developers to potential problems that might affect how the software works or cause issues in operations. Shift-left testing can be smoothly integrated into the development process by making software easy to test. This creates a culture of teamwork and quality assurance from the beginning.

Note
Testability is all about making the software easy to test. This involves coding in a way that allows testing to happen smoothly, such as using unique markers or IDs. These make it easier to find and fix potential issues early in development.

Types of shift-left testing

Traditional shift-left testing

Shift-left testing involves performing testing activities earlier in the development process, typically starting with the requirements and design phases. The goal is to catch and fix issues early so they don’t cause problems at later stages. This approach encourages early teamwork between developers and testers and sets the foundation for other testing methods.

Incremental shift-left testing

Incremental shift-left testing supports continuous and incremental testing throughout the development lifecycle. Rather than having a single testing phase, testing activities are distributed and performed incrementally as new features or code units are added. This process ensures that each addition is thoroughly tested before integrating it into the existing codebase, promoting a more dynamic and responsive development cycle.

Agile/DevOps shift-left testing

Agile/DevOps shift-left testing follows the ideas of Agile and DevOps. It emphasizes teamwork, automation, and continuous testing. In this method, testing is part of development, with developers doing some testing and testers helping them with coding. Automation tools give quick feedback on code changes, which fits well with Agile and DevOps development’s fast and iterative style.

Model-based shift-left testing

Model-based shift-left testing involves creating models or representations of the software’s functionality, behavior, or architecture before actual development occurs. These models are used to design test cases and validate the software against expected outcomes.

Using models early in the development lifecycle enhances test design, helps identify potential issues, and ensures that the final product aligns with the planned specifications. Model-based shift-left testing is particularly effective in complex systems where visualizing and validating complex interactions is critical.

Learn more about the four types of shift-left testing.

Pros and cons of shift-left testing

Pros of shift-left testing

Spotting problems early: Shift-left testing allows for the early detection and resolution of issues, reducing the chance of critical defects moving to later stages of development.
Saving costs: Identifying and fixing issues in the early stages of development is more cost-effective than handling them in later phases, leading to overall cost savings.
Quicker release: By integrating testing early and continuously, development cycles become more streamlined, enabling faster delivery of high-quality software to end-users.
Better teamwork: Shift-left testing fosters better communication and collaboration between development and QA teams, creating a cohesive working environment.
High-quality software: Focusing on continuous testing and early issue resolution results in higher software quality, increasing customer satisfaction.

Cons of shift-left testing

Resource requirement: Implementing shift-left testing requires additional resources, including skilled testers, automation tools, and collaboration efforts, which may increase initial costs.
Learning new ways: Shifting left often involves a cultural change and a learning curve for developers and testers as they adapt to new processes and responsibilities.
Potential overhead: The focus on early testing may lead to potential overhead, mainly if not managed efficiently, impacting development speed.
Automation challenges: Depending heavily on automation introduces challenges such as initial setup, maintenance, and the need for skilled automation engineers.
Risk of missed issues later: While shift-left testing is effective for early identification, there’s a risk of missing specific issues that may manifest in later stages of development or specific integration scenarios.

Shift-left vs. shift-right testing

Shift-right testing is a software testing approach where the testing activities are performed later in the development process, generally in the production environment or after the software has been deployed. This testing step involves collecting feedback from end-user interactions and behaviors to monitor and evaluate the software in a live environment.

Features	Shift-left	Shift-right
Focus	Early in the development lifecycle	Late in the development or post-production
Testing Stage	Starts from the requirement or design phase	After deployment or during production
Timing of Testing	Throughout the development process	After the software is deployed
Objective	Early issue identification and prevention	Identifying issues in real-world scenarios
Risk Mitigation	Reduces the risk of major defects and issues reaching later stages	Identifies issues that may surface in production
Deployment Control	Focuses on ensuring code quality before deployment	Monitors and manages code in a live production environment
Cost of Fixing	Lower as issues are caught early	Higher as issues are discovered later

Commonly asked questions on shift-left testing

What are shift-left and TDD?

Shift-left refers to moving testing activities to earlier stages in the software development lifecycle, starting as early as the requirement and design phases. It highlights aggressive testing, a collaboration between developers and testers, and the integration of automated testing tools to identify and address issues early on.

Test-Driven Development (TDD), on the other hand, is a development methodology where test cases are written before the actual code. TDD involves creating small, focused test cases defining the expected functionality and writing code to pass those tests.

The combination of shift-left and TDD facilitates a culture of continuous testing, early issue identification, and collaboration between development and testing teams, ultimately leading to more reliable and maintainable software.

What is the shift-left approach in BDD?

The shift-left approach in Behavior-Driven Development (BDD) involves integrating testing activities earlier in the development process, typically at the requirement and design phases, and aligning them with BDD principles. BDD highlights collaboration among cross-functional teams, including developers, testers, and business stakeholders.

In this context, shift-left encourages writing executable specifications using natural language, often called Given-When-Then scenarios, before developing any code. BDD tools like Cucumber or SpecFlow can translate these scenarios into automated tests. This enables a shared understanding between technical and non-technical team members and contributes to creating more effective and reliable software.

Who performs shift-left testing?

Shift-left testing involves developers and quality assurance (QA) professionals working together to test software early in development. Developers take on testing tasks, and QA professionals actively contribute to planning and automated testing. It’s a shared effort to catch and fix issues immediately. Other team members, like business analysts and product owners, may provide input during requirement discussions and user acceptance testing.

What is the difference between shift-left and waterfall?

In the Waterfall model, software development follows a rigid, step-by-step process where testing happens only after complete coding. All requirements are to be known from the beginning. This can result in delays and higher costs if changes are required later.

We change shift-left testing by moving testing activities earlier, starting with requirements and design. Developers and testers work together from the beginning, allowing quicker issue identification and a more flexible approach. Shift-left is better suited for adapting to changes, making it more aligned with agile development practices.

What is the shift-left approach in DevOps and API testing?

In DevOps

The shift-left approach in DevOps refers to integrating testing and quality assurance practices early in software development. In a DevOps environment, where collaboration between development and operations is essential, shift-left involves bringing testing activities closer to the initial stages of coding and design. By implementing shift-left in DevOps, teams aim to catch and address issues early, reducing the possibility of defects progressing to later stages of deployment.

In API testing

The shift-left approach in API testing involves testing APIs early in development, even before the graphical user interface (GUI) is developed. This approach identifies the significance of APIs in modern software architecture and emphasizes validating their functionality, performance, and security at an early stage. By conducting API testing earlier in the development lifecycle, teams can identify and rectify issues related to data communication, endpoints, and integrations, ensuring a solid foundation for the application.

Final thoughts on mastering shift-left testing

In conclusion, Mastering shift-left testing is not just a technological shift but a cultural one. By adopting this innovative approach, QA professionals can elevate their roles, contribute to stronger software development, and ultimately ensure the delivery of high-quality products to end-users. As the software industry evolves, mastering shift-left testing becomes a key differentiator for those seeking excellence in QA practices. Happy testing!

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Ashutosh Mohanty

Ashutosh has 3 years of experience in software testing. He has performed different types of testing such as load, API, and database as well as knows a wide range of testing tools. He has a bachelor's degree in Electronics and Telecommunication Engineering.

Throughout his entire life, he always wanted to help others and now he's helping a large number of groups by sharing knowledge through his writings.

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What Is Shift-left Testing?

What Is Shift-left Testing?

Shift-left testing in software testing

Table of contents

Introduction to shift-left testing