The demand for software quality is ever-rising. Agile and DevOps teams are expected to release in shorter and shorter amounts of time. Traditional approaches just do not cut it anymore. As a response to this need, shift-left testing emerges as a solution for bottlenecks in the old development-testing process.

In this blog, we’ll walk you through the concept of shift left testing, its benefits, and how to implement them into your software development life cycle.

What is Shift Left Testing?

Steps To Shift Left Testing: requirement analysis, design, development, test, then production and maintenance

Shift left testing is a software testing approach that shifts all testing activities to earlier stages of the SDLC. Traditionally, testing happens at the end (the right side) of the process, which contrasts with the shift left approach where testing happens at the beginning (the left side).

Benefits of Shift Left Testing

Let’s first look at the traditional software development life cycle.

Traditional software development life cycle

You can easily see that testing lies at the very end of the cycle. At first, it makes sense. You are supposed to code everything before you test it, right? However, there are 2 reasons why this is not the optimal way:

If testing is done at the very end of the sprint, there is just not enough time to test thoroughly.
Even if a bug is found and sent back to the dev team for troubleshooting, the devs won’t have enough time to fix the bug.

The consequence? A snowball of disaster.

When QA teams are busy testing, the devs can’t do anything else except from hoping that no bug was found. It is frustrating when you are about to start a new project and the testers come up to you to announce a bug in your old project, and you have to abandon everything to fix that bug.
Increase in cost of fixing bugs
Longer time-to-market since instead of being released, the software is sent back to be reworked.

Shift left testing was born to address all of that.

Here’s how the workflow of shift left testing should look like:

Software Development Life Cycle with shift left testing

Testers are involved from the very beginning. Coding and testing happens simultaneously. TDD is a commonly used practice in shift left testing to make this collaboration possible.

How To Do Shift Left Testing?

Let’s go through each phase of the shift-left SDLC.

Conception and Initiation: business stakeholders, PMs, product owners, the dev team, and the QA team work together to align on project goals, scope, and high-level objectives.
Requirement gathering and analysis: testers participate and provide input to ensure that requirements are clear and testable. Developers ensure that requirements are technically feasible.
System design: developers and testers work with system architects to review the design for functionality, scalability, and testability.
Coding - testing: this is where the beauty of shift left testing lies. TDD (test-driven development) is used: developers collaborate with testers to implement unit tests alongside the code. DevOps team can setup CI/CD pipeline to run automated tests that provide real-time feedback on code quality. Any bugs found are immediately fixed.
Integration: code for individual components are merged together. Integration tests are run to ensure that those components work together seamlessly.
Deployment: testers run one final check to ensure final build’s stability. The DevOps team monitors production environments to resolve any deployment issues that may arise.

Learn more: The Bug Life Cycle and Bug Management Best Practices

Why TDD For Shift Left Testing?

Let’s learn more about TDD and why it is so essential in the shift left testing philosophy.

TDD (test-driven development) follows 3 steps: Fail - Pass - Refactor.

The Fail-Pass-Refactor cycle of TDD

Testers start the TDD process by writing a test case for one specific feature (even before writing code). Since there is no code written yet, this test is supposed to fail.
Developers then start coding that feature until it passes the test.
They then refactor the code to improve it in terms of simplicity, readability, maintainability, etc.

Why is this a good process? There are 2 reasons:

Every piece of code has a specific purpose (passing the test). If it passes the test, it meets its intended functionality.
Developers have a safety net available even before they start coding.

TDD embodies the spirit of prevention over treatment.

Learn more: What is TDD? A Complete Guide

Challenges of Shift-left Testing

Cultural shift: embracing shift left testing means embracing an entire culture reset in the organization. It is honestly a disruption to the daily routine of anyone involved. Leaders of the teams should have open communication and encourage collaboration to ensure a seamless transition.
Collaborative planning: shift left testing also shifts planning to earlier stages. Testers work with business analysts, developers, and stakeholders to define acceptance criteria and design tests based on these criteria.
Breaking Communication Silos: persistent gaps between QA and development teams due to limited interaction must be broken down to facilitate good shift left testing.

Shift Left vs Shift Right Testing

In contrast with shift left, shift right is where testing is shifted to the right i.e. testing in production and post-release environments. Shift right has its own advantages: testing in real-world environments provides the highest level of realism.

Here is a quick table of comparison:

Aspect	Shift-Left Testing	Shift-Right Testing
Focus	Early testing during the development lifecycle.	Testing in production and post-release environments.
Objective	Prevent defects by catching them early.	Identify issues in real-world usage and improve user experience.
Key Activities	Unit testing, integration testing, static code analysis, TDD/BDD.	A/B testing, performance monitoring, canary releases, production testing.
Stage in SDLC	Conducted during planning, design, and coding stages.	Conducted after deployment in real-world or simulated environments.
Tools Used	Static code analyzers, unit testing frameworks (JUnit, PyTest), CI/CD.	Monitoring tools (New Relic, Dynatrace), analytics tools, feature flags.
Approach	Proactive: Prevent issues before they occur.	Reactive: Detect and address issues in live environments.
Stakeholder Involvement	Developers, QA, product teams involved early.	DevOps, operations, and product teams collaborate post-deployment.
Feedback Loop	Early and continuous feedback during development cycles.	Continuous feedback from real-world usage and user behavior.
Automation Role	Heavy use of test automation in CI/CD pipelines.	Automated monitoring and logging in production.
Purpose	Ensure code quality, functionality, and performance pre-release.	Validate system behavior, reliability, and performance post-release.
Cost of Fixing Bugs	Lower due to early identification.	Higher, as bugs are fixed post-deployment.
Common Use Cases	Agile development, DevOps, critical applications with high quality demands.	Continuous delivery, user experience optimization, experimentation.

The Importance of Continuous Testing in Shift Left Strategy

Continuous testing involves running tests frequently throughout the development lifecycle. It speeds up time-to-market and ensures high-quality releases that meet customer expectations.

The constant feedback loop between testers and developers that continuous testing creates allows bugs to be identified and fixed early. While automation isn’t mandatory for continuous testing, it’s highly recommended, especially for large-scale projects.

To learn more about the benefits and challenges of continuous testing, have a look at these two articles:

Shift Left Testing vs. Continuous Testing

Have a look at this table to understand the differences in 2 approaches:

Aspect	Shift-left Testing	Continuous Testing
Definition	Testing activities are moved earlier in the software development lifecycle (SDLC).	Automated tests are executed continuously throughout the SDLC.
Goal	Identify and address defects early in the development process.	Provide immediate feedback on the quality of the software.
Techniques	Unit testing, code reviews, static analysis, early integration testing.	Automated unit tests, integration tests, functional tests, etc.
Focus	Early defect detection and prevention.	Ongoing quality assurance and feedback.
Benefits	Reduced cost of fixing issues, shorter feedback loop, faster delivery.	Maintains high confidence in software quality, faster release cycles.
Integration	Integrated into the beginning or middle stages of the SDLC.	Integral part of the continuous integration and delivery pipeline.

How To Perform Shift Left Testing with Katalon Platform?

Katalon logo

Katalon Platform is a comprehensive test automation solution and quality management platform for web, mobile, API, and desktop applications. It provides a unified platform for teams to plan, design, execute, and manage automated testing efforts.

Katalon Platform supports all 4 key elements of shift left testing. Early testing and continuous integration/continuous delivery can easily be achieved thanks to seamless integration with popular CI/CD tools as well as collaboration tools such as Slack, Microsoft Teams, Git, bringing transparency and enhanced communication between team members.

Katalon also offers test management capabilities. Testers can capture application elements and store them in the Object Repository, which is essentially a centralized repository to store test artifacts. These test artifacts, test cases, and data can be shared across team members and reused across projects, improving test reusability.

Curious? Witness the power of Katalon in action here:

Download Katalon and Start Testing Better

Shift Left Testing FAQs

1. Why is Shift-Left Testing important in DevOps?

DevOps emphasizes Shift-Left Testing to identify and fix defects earlier in the software development process. This approach reduces costs, accelerates delivery, and improves software quality, leading to better customer satisfaction.

2. Can Shift-Left Testing be applied to automation and performance testing?

Yes, Shift-Left Testing applies to all types of testing, including automation, performance, unit, and integration testing. The idea is to perform these tests earlier in the lifecycle to prevent defects from propagating.

3. How is Shift-Left Testing different from traditional testing?

Traditional testing occurs late in the development process, often after coding is complete. Shift-Left Testing moves testing earlier, during planning, design, and development, to catch issues sooner and prevent defects.

4. Are Shift-Left Testing and Test-Driven Development (TDD) the same?

No, they are distinct but related. Shift-Left Testing focuses on early testing at every stage of the lifecycle, while TDD involves developers writing tests before writing the actual code. TDD is a specific practice that supports the Shift-Left approach.

5. Who introduced the concept of Shift-Left Testing?

Larry Smith coined the term "Shift-Left Testing" in 2001, proposing it as a solution to integrate QA and development earlier in the software lifecycle.

6. What are the benefits of Shift-Left Testing?

Early defect detection and prevention, reduced testing costs and faster delivery, improved collaboration between QA and development teams, higher-quality software, and fewer production issues.

7. Is Shift-Left Testing suitable for Agile and DevOps?

Absolutely. Shift-Left Testing aligns well with Agile and DevOps by promoting early and frequent testing, continuous feedback, and collaborative workflows.