As the software industry evolved, so did new trends and operating models, with each 'software model' aimed at increasing efficiency at each stage of 'software development.' More efficiency was required because any delay in project execution and delivery could cause the product's shipping or launch to be delayed.
The 'Waterfall Model' was one of the most widely used software development models, in which all activities in a software development lifecycle, namely Requirements Gathering -> Software Design -> Coding (Development) -> Product Testing, were carried out sequentially. The main disadvantage of the 'Waterfall Model' was that testing was not performed at every stage, so defects were discovered only after the 'product development' was concluded.
If the defects are of minor severity, developers can fix them and submit the changes for review. If the severity is 'very high,' the scenario changes dramatically, and the fix may have unintended consequences. In such cases, there may be a delay in delivering the product to the customer. In such a model, the testing phase was at the very end of the SDLC, which is ideal if your product is defect-free, which is never the case.
Shift left testing can be performed in two main ways:
Shift Left in Agile - Shift-left testing is done in iterations, as the name implies. It is mostly used for development testing as opposed to operational testing. Agile shift left testing is rising in popularity, and organizations are implementing it in response to project requirements and timelines.
Shift Left Traditional Testing - The traditional shift-left testing strategy emphasizes unit, component, and integration testing. API testing and test tools are used to accomplish this. It does not emphasize acceptance and system-level testing more.
Why Is It Known As A Shift Left?
We're about to examine the connection between agile software development and the shift-left testing movement. However, let's first discuss some etymology before moving on. As you've seen, "test often, and start as early as possible" is the essence of shift-left testing. However, why is it called "left"?
That's most likely a consequence of the fact that English and the majority of western languages are read from left to right. If we are to represent sequential phases of any kind, the earliest phase will be at the extreme left and we will progress from there (similar to the phases we have in the waterfall model). However, do not assume that shift-left testing advocates that testing should be a distinct stage, only included at the beginning rather than the end of development. As you are probably aware, there shouldn't be phases in the development of truly agile software; instead, activities should be ongoing and take place in brief iterative cycles.
Why Adopt a Shift Left Strategy?
Any bugs that do surface when testing is put on hold until the end of development are typically more challenging to address. Since all the code has already been written, the only way to resolve their issue is to completely redesign the software. The effects of such a strategy would be:
Cost will rise because the software must be sent back and completely rewritten.
longer time to market because these reworks will take longer to finish
The Shift Left Testing strategy introduces a procedure that enables programmers to find bugs frequently and early. The easiest bugs to fix are those found when developers are writing or reviewing code because these units of code are small and a lot easier to manage. The scope of the code expands once it is merged into the main development branch, increasing both the time and effort needed to identify errors.
Empowering 'test teams' through shift-left testing
As new software models emerged, people realized the value of testing. Because it had a significant impact on project deadlines and cost, keeping testing as a one-time activity entailed a significant number of risks.
This realization gave rise to the concept of 'Shift Lift,' or shifting the testing phase to the left and empowering the test team by involving them in project-critical activities. In the earlier testing methodology (called Shift Right), testing occurred at the 'extreme right'/end of the development cycle, whereas in the Shift-Left methodology, testing occurs at each developmental stage. In a traditional software development approach, test teams operate in silos because their primary responsibility is to improve product quality by identifying and reporting bugs. A critical stage of product planning and development saw little or no involvement of testers.
The 'Shift-Left' concept involves the testing team in all phases of product development. With this approach, the testing team could collaborate with other stakeholders such as the development team, product team product development, and so on, promoting a 'testing mindset' at an early stage of development. Because the test team has the opportunity to interact with members of other teams, they will gain a better understanding of how to write effective test cases that will aid in the quality of the product.
As a result, the concept of 'Shift-Left' not only aids in the discovery of bugs at an early stage of product development; it also aids the testing team is collaborating with other stakeholders, improving domain competency, and developing more realistic test cases.
The advantages of Shift-Left testing
As you incorporate shift-left testing into your SDLC, you may experience a number of advantages. The ones listed below, in my opinion, are the most beneficial.
Automation - Shifting left enables testing to be fully automated. The advantages of this automation include:
fewer human mistakes
fewer production problems
increased test coverage (multiple tests being conducted in parallel)
Testers can concentrate on more enjoyable tasks
Increased delivery speed - The concept of starting sooner and finishing sooner is not revolutionary. Early in the software development cycle, critical bugs can be found and fixed more quickly. As a result, the interval between releases is cut down significantly, speeding up delivery.
Enhanced test coverage - The software can be quickly assessed or tested for all the features, functionalities, and performance when the test execution is started at the beginning of the development process. The test coverage percentage naturally rises with shift-left testing. The overall quality of the software is significantly impacted by increased test coverage.
Improves product quality - With rigorous and frequent code quality checks, the shift left testing methodology improves the overall quality of the code. It enables prompt communication between stakeholders, developers, testers, and feedback, which helps to raise the caliber of the code. This guarantees that the final product your customers receive is stable and of high quality.
Teamwork - Teamwork is key, so foster cohesion among your developers and testers by preventing friction between them from becoming a bottleneck.
How Should the Shift Left Testing Approach Be Used?
What can your company do to begin shift left testing? Let's find out.
Embrace test automation
Given that shift left testing necessitates frequent testing, the development team should make use of test automation. It relieves the testing team of the burden of quickly reporting on the stability of the code and determining whether or not all functionalities are operating as intended. Shift left testing is greatly aided by automation, which also ensures that few bugs are discovered later in the software development life cycle.
Early on in the project's lifecycles, requirements and designs are validated as part of static testing. Static testing's goal is to identify flaws early in a product's life cycle before they become very expensive to fix in the project's later stages. Utilize the proper checklists to validate the requirements and design. Enter errors in a tool for defect management.
Continuously provide feedback
Throughout the entire software development lifecycle, developers and testers should receive timely feedback. This makes it easier for everyone to participate and prevents unwelcome gaps between teams.
Unified testing approach
This is a comprehensive, high-level testing strategy that covers end-to-end testing from unit testing through operational readiness testing (ORT), user acceptance testing (UAT), and post-deployment testing. The plan will outline precise roles for each stage of quality control. By analyzing dependencies on environments, stubs, automation, and test data, you can make sure that the various teams can meet the demands.
Invest in planning
Developers and testers should begin planning how to structure coding and testing as soon as the product requirements have been finalized.
Construct Coding Standards
Your development team must first decide on the same coding standards. There needs to be agreement among all developers. It expedites their code reviews while also ensuring higher code quality. Coding standards should, in essence, reduce the number of bugs because they prevent the use of bad code.
Construct Quality Standards
Developers are not initially trained in testing, so QA professionals should lay out the quality expectations so that the developers who are running tests are clear on the kinds of bugs to look for.
Educate testers on coding
Agile, in its purest form ,calls for developers to test and testers to code. Of course, neither is expected to be an expert in a field outside of their expertise. But developers ought to be able to conduct intermediate-level tests, and QAs ought to be familiar enough with coding to insert some temporary fixes when necessary. Testers who have a foundation in coding are better able to perform code reviews and contribute significantly to sprint teams. The ability to read and modify simple code, such as an automated test or rewrite fundamental methods, is a requirement for testers.
Include developers in test activities
When code is tested by developers before being merged into the main branch, the resulting code is cleaner and less prone to errors. They are smaller and more comprehensible, making individual code units simpler to test.
For each test scenario, a risk-based analysis is done to determine the impact and likelihood of failure. Functional, non-functional, and regression testing all use this method of analysis. After the test cases are created, rank them in order of importance using the results of the analysis. Go over the consequences of failure. From the development team, assess the risk of failure.
With the shift-left strategy, we can find bugs more quickly and the development team can address them before they have an impact on the end-user. In addition to significantly lowering overall costs and speeding up release cycles, this strategy improves quality throughout the entire software development life cycle.