What Is Shift Left Testing Strategy: Complete Guide

In the dynamic world of software development, where both the speed of delivery and product quality are priorities, the testing phase is of great importance. Many of us have experienced the problems associated with starting testing too late in the software development cycle. As a result, we faced the challenge of meeting our product lunch deadline, maintaining high product quality and dealing with costly defect repairs. This is a typical scenario in traditional methodologies where test are added too late in the project stages. To avoid such experiences, the Shift left testing strategy comes to our aid.

What is shift-left testing?

Shift left testing is an approach that moves testing activities to earlier stages of the software development lifecycle. In practice, this means including testers in the project as early as the requirements analysis and design phase. The main goal of adopting this strategy is to address issues early and to fix errors, which reduces the coast and time needed to fix these errors, enhances software quality and also increases the tester’s understanding of the project. Thanks to this, the testers can not only detect defects faster but also propose improvements.

Shift left vs shift right

While the Shift left testing strategy involves the earliest possible including of tests in the project and resolving issues during the development phase, the Shift right testing strategy involves testing after the software development process is completed, directly in the production environments. However, this does not mean that by choosing one of these strategies, we must give up the second one. In fact, we could say that Shift right testing is a natural complement to Shift left testing and they can function together in one project.

Shift left testing helps us to detect and fix defects quickly, and to deliver the best-performing software. Shift right testing, on the other hand, is focused on monitoring the application after it has been released in the production environment.

Types of shift-left testing

For the Shift left testing strategy to be effective, it must not only be implemented quickly, but also be based on a variety of tests conducted at all levels. This approach is not just about the number of tests performed, but about introducing specific techniques at the right moments in the development life cycle. The following test types from the basis of this approach and cover software verification, starting from the smallest code modules to testing the entre application.

Unit tests

Unit testing involves verifying the smallest parts of software. Each part is tested separately, in isolation, and any interactions with external processes are simulated or tested using mocks. The goal of their tests is to detect defects at the beginning of the software development process to improve code quality by eliminating them early.

Integration testing

Integration testing is another type of testing in the development cycle, performed on a larger part of the application. It’s used to verify that interconnected software modules and components work together correctly and meet the requirements. There are responsible for detecting defects that may appear in the interactions between modules.

API testing and contract testing

In API testing, we verify endpoints and HTTP methods, often before integration. Contract testing, on the other hand, targets to confirm communication compatibility between the API provider and the user. While these may seem like two separate things, in practice, they come down to verifying the correct operation of individual services and ensuring that these services “communicate” with each other correctly.

UI testing

User interface Testing is designed to verify how the end-user sees and interacts with our product. The main goal of these tests is to verify that interfaces elements – such as buttons, text fields, icons, menu – work as expected. However, we focus not only on their functionality, but also on appearance and usability, so that the final product is intuitive and user-friendly.

Shift left tools

Effective and efficient implementation of the shift left approach also requires the use of right tools that automate processes and improve team collaboration. These should be selected and implemented at the very beginning of the software development cycle to ensure that the entire process runs smoothly. The choice depends on many factors, as each project is unique and may require a different set of technologies. This includes everything from static code analysis tools to frameworks used for unit and integration testing, as well as CI/CD systems or even AI agents tools. However, the choice of tools shouldn’t be limited only to code development alone, it’s important to provide tools that facilitate team management. Without them, no software development methodology could function effectively.

Best practices for shift-left testing in agile development

Now, let’s move to the next point: best practices, because they are crucial for a proper and effective implementation of the Shift Left Testing in the software development cycle. Some of them have already been mentioned earlier in this article, but it is worth to return to them and discussing them in more details.

Practice No. 1 – Early Involvement of testing teams

This is the first practice you should implement to successfully implement Shift left testing in your company or project. It enables testers to get to know the requirements right from the start, which increases their project knowledge. Additionally, they should participate in reviewing user stories, specifications and designs, to identify risks and defects before implementation.

Practice No. 2 – Requirements-Based Testing

This practice involves designing tests based on functional and non-functional requirements to ensure that all software components are verified and aligned with business goals. As a result, any potential discrepancies can be quickly identified and resolved.

Practice No. 3 – Test automation

Test automation enables faster execution of repetitive and time-consuming tests. This is specially effective for long projects where the same tests are performed multiple times. The earlier we start automating tests, the sooner we save time and budget. Also, potential bugs are detected faster, allowing for quicker resolution.

Practice No. 4 – Static analysis of code and documentation

Static code analysis involves reviewing code without executing it to eliminate defects at the beginning. This also enabled rapid detection and elimination of non-compliance with standards or security vulnerabilities. Similarly, documentation analysis helps us identify gaps and update them quickly. Documentation also serves as a knowledge base; regularly reviewing and updating it makes it easier to gain project knowledge and maintain the standards established at the start.

The benefits of shift-left testing

As mentioned earlier, the basis of the shift left testing approach is starting the testing process as early as possible during the development cycle. This approach brings a range of benefits, improving not only quality and efficiency but ultimately contributing to the success of projects. Some of these benefits of shift left testing are presented below.

Early understanding of requirements

Understanding requirements early allows you to create effective test cases and helps avoid misunderstandings that may result from different interpretations of assumptions. Additionally, it allows for testing a larger number of scenarios, which leads to better quality of the final results.

Faster defect detection and resolution

This is one of the most important benefits of the shift left approach. By starting tests at an early stage, we are able to detect defects that don’t require a lot of work or time to resolve. There is no downtime in the software development process, allowing us to continue with ongoing work.

Faster and more frequent releases

With a better understanding of the product, the development teams is able to deliver results of their work faster and more often. This enables faster product development that delivers new functionalities to the end user more frequently.

Better product quality

By introducing tests at an early stage, we can perform more test and cover more areas. This provides better protection for the product, preventing not only minor defects but also critical errors that could make the product unusable. Ultimately, this results higher customer satisfaction.

Cost reduction

This is perhaps the most important benefit of the shift left testing from a client’s perspective. Detecting and fixing defects is much cheaper if it is identified at an early stage than in the final product. Thanks to this, the team is able to avoid expensive repairs (hotfix) and longer repair work at later stages of development phase. In summary, this approach allows for better budget management and a higher return on the overall investment.

The dangers of shift-left testing in agile

Shift left testing, like any other practice, offers a number of benefits, but it also carries some risks. Therefore, it is crucial to implement it correctly to minimize the probability of these risk occurring.

Increased workload for the development teams

Shift left testing involves introducing testing earlier in the project, which translates into more tasks for testers and developers from the beginning. Improper work organization can lead to delays, lower code quality, overwork and high staff turnover in the project.

The risk of neglecting later testing stages

In this case, there is a risk that testing will be limited or completely stopped at later stages of the development cycle, e.g. after release. It is important to remember that when we use the shift left testing approach, testing should not be stopped after achieving certain goals. Testing should be continued, perhaps with a different scope or in a different environment, but it shouldn’t be skipped or forgotten.

The need for precise planning and management

Shift left testing approach requires preparation and planning to work properly. We must remember when to implement specific tests, their deadlines, and how much time is needed for testing to ensure nothing is missed. We also need to keep in mind about risks such as unplanned downtime or blockers, team members absences, and the time it takes to learn new tools.

Greater challenges in fast-iterative environments

Frequent iterations require frequent testing, which is time-consuming. As a result, there may not be enough time to perform all the necessary tests and, over time, it may turn out that perform fewer tests than we originally planned. Good team time management and proper work planning reduce the risk, but it’s not immune to sudden changes, which are difficult to handle in a dynamic environment.

How to get started with shift left testing?

To effectively implement a shift left testing strategy, it is important to start by changing the organization mindset and promoting the participle that the entire team, not just testers, is responsible for software quality. A key step is also involve testers and developers already at the requirements analysis stage, which enables the detection of initial inconsistencies before any code is written. At the same time, emphasis should be placed on test automation, which allows for shorter testing cycles and provides faster feedback. Ultimately, the most important factor is ensuring the consistency of all elements, as only the full implementation of these practices guarantees that the intended benefits will be achieved.

Shift left testing at Droids On Roids 

At Droids on Roids, we have been practicing the shift left approach for years, effectively combining it with shift right practices to ensure the product is fully supported. Our test engineers are involved from the beginning of the project, helping to define acceptance criteria and identifying potential risks. They participate in the entire development process, ensuring quality at every stage which is crucial when creating mobile applications, the development of which is characterized by high dynamic and constant changes. This approach allows us not only to avoid potential risks but also to improve the entire team’s workflow, and as a result, it builds the trust of our clients who entrust us with their ideas.