21 December 2023
07 Min. Read
Shift Left Testing: Types, Benefits and Challenges
Fast Facts
Get a quick overview of this blog
Get to know about shift-left testing approach
Learn about the differences in shift-left testing and the traditional methods of testing
See how shift-left testing is a boon for agile architectures like microservices
Learn about the HyperTest way to implement shift-left testing
Have you ever been involved in managing a software project that exceeded its budget or faced time constraints? It's a common experience. Despite common misconceptions, inadequate planning isn't the sole culprit when a project surpasses its deadline. The real challenge lies in the code validation process of the project.
In essence, the pivotal factor is software testing. Specifically, insufficient and delayed software testing tends to be the root cause. One proposed solution to address this issue is to implement shift-left testing.
What is Shift-Left Testing?
Shift Left testing is an approach that involves moving the tasks related to testing earlier in the development process. This means that testing tasks that are traditionally done at a later stage of the operations should instead be performed at earlier stages–particularly those related to API testing.
This concept is rooted in the idea that finding and fixing defects early in the development cycle is less costly and time-consuming than doing so later.
The Focus of Shift-Left Testing:
These are smaller, more atomic tests assessing the output of the System Under Test (SUT) using defined inputs.
Offers rapid and highly precise feedback to developers regarding breaking changes. This allows developers to quickly debug, fix, and release patches.
Typically, unit or integration tests are employed, excluding End-to-End (E2E) tests.
These tests should address both functional and logical issues.
Where the Shift-Right/ Traditional Testing Lacks?
Conventional models position testing near the deployment phase, causing a bottleneck in the release process. This bottleneck arises from the accumulation of numerous changes, impeding efficient testing and subsequently delaying releases.
Principles of shift-left empower testing teams to enhance developer oversight in the release process. This is achieved by facilitating developers to test their changes as soon as they are merge-ready, bypassing the need for QA team involvement.
The shift-left testing process operates concurrently with the development process, granting developers the capability to implement minor changes to the application. These changes can be promptly tested and readied for immediate release.
Shift-Left vs. Shift-Right Testing
Aspect | Shift-Left Testing | Shift-Right Testing |
Timing | Early in the SDLC | Later stages, including post-release |
Focus | Prevention of defects | Detection and resolution of issues in real-world use |
Methods | Unit, integration, and early system testing | Performance, usability, and A/B testing |
Involvement | Primarily developers and testers | Involves operations and end-users |
Feedback Loop | Immediate and frequent feedback during development | Feedback after deployment or in late stages |
Cost of Defect Resolution | Lower, as issues are simpler to fix early in the cycle | Higher, as issues may require more complex fixes |
Goal | Enhance quality and collaboration, reduce time to market | Ensure reliability, usability in real-world scenarios |
Why Shift-Left Testing is Needed?
It is an essential methodology because it emphasizes the integration of testing early and often in the SDLC. The key reason for its necessity lies in its ability to identify and address defects earlier, which significantly reduces the cost and time required for fixing issues later in the development process.
In traditional models, testing is often conducted after the completion of the development phase, leading to the discovery of bugs and errors late in the cycle. This not only increases the complexity of resolving these issues but also escalates the costs involved.
By shifting testing to the left, i.e., closer to the start of the project, teams can ensure that code is tested as it is written. This approach not only enhances the overall quality of the software but also aligns with agile and continuous delivery practices, promoting faster release cycles and better collaboration between developers and testers.
This translates into more efficient resource utilization, improved product quality, and a higher return on investment, making shift-left testing a strategic priority in modern software development.
Benefits of Shift-Left Testing
For development teams, the shift towards earlier testing in the process presents a host of advantages. These benefits can be encapsulated in two distinct outcomes: accelerated innovation and a shortened time to market for new features.
Here are several more advantages:
Automation: Shifting testing to the left enhances the effectiveness of automation. This yields several key advantages, including a significant reduction in human errors, more comprehensive test coverage through concurrent testing, the ability for testers to focus on higher-priority activities, and a decrease in production issues.
Faster Innovation: Early API testing facilitates the enhancement of code sanity without impeding development speed. Continuous testing not only reduces expenses related to redundant testing but also boosts organizational confidence in APIs.
Delivery Velocity: The adage "faster is earlier" holds true in this context. Detecting defects early in the production cycle makes rectification much simpler. Consequently, the time between releases can drastically shrink, leading to improved software quality.
Lower Costs & Higher Revenue: Early and frequent API testing substantially diminishes remediation costs as flaws can be addressed before posing risks in production. Automated testing ensures that new releases are bug-free and less likely to require future rework, allowing developers to swiftly meet customer needs and, in turn, boosting revenue.
Increased Satisfaction: A primary advantage of the shift-left strategy lies in the prompt delivery of software with fewer flaws. This enables products to maintain a competitive edge or even enhance their lead in the market by meeting customer expectations and delivering outstanding customer experiences.
Types of Shift-Left Testing
Shift-Left Testing approach contributes to quicker identification of defects, improved collaboration between development and testing teams, and ultimately leads to the delivery of higher-quality software. Several types of Shift-Left Testing methodologies are employed in the software development process:
Unit Testing:
Unit testing involves testing individual units or components of a software application in isolation. Developers perform unit testing to verify that each unit of code functions as intended.
Example: In a web application, a unit test might validate the functionality of a specific JavaScript function responsible for form validation.
Integration Testing:
Integration testing assesses the interactions between different units or components to ensure they work together seamlessly. This type of testing helps identify issues that may arise when integrating various modules.
Example: In an e-commerce platform, integration testing could involve verifying that the shopping cart module integrates correctly with the payment processing module.
API Testing:
API testing validates the communication and data exchange between different software components. It ensures that APIs function correctly and consistently.
Example: For a weather application, API testing may involve verifying that the application accurately retrieves and displays weather data from an external API.
Component Testing:
Component testing focuses on testing individual components or functional units of an application to ensure they meet specified requirements.
Shift-Left Performance Testing:
Performance testing, usually performed later in the development cycle, can be shifted left to identify and address performance-related issues early on. This includes assessing how the application behaves under different load conditions.
Example: Running performance tests on a web application to ensure it maintains responsiveness and stability when subjected to varying levels of user traffic.
How to Implement Shift Left Testing Approach?
If you have a micro-services architecture, a shift-left testing approach becomes by default the best testing approach and something you can easily put in place. Your team has done the hard work in splitting your central code base into several smaller, distributed code-bases to accelerate development. All that you now need to do is adopt a testing practice that can test these code-bases independently.
Consider the benefits:
In a micro-services architecture , services are loosely coupled that give devs the freedom to make and deploy changes to each of these services independently.
A shift-left approach tests these commits one at a time, independent of the dependent services or alongside them, but providing quick bit-sized feedback on what can be fixed immediately.
Here's a standard step-by-step guide to follow when implementing shift=left testing, but it is all dependent on the organization and your company’s need first.