Regression Testing Services

Regression Testing

Structured and thorough testing leads to high-quality software. Why? Because as DevOps teams have seen time and again, introducing even minor changes into existing code can have serious — and unpredictable — downstream consequences. When new code is released, it’s important that some level of testing be carried out to ensure its functionality. The imperative to retest old code that the product previously passed is equally important to confirm that any new changes do not introduce past defects or create new ones; effects which are called “regressions”. While regression testing can appear to be a simple testing process, it in fact can be quite challenging due to limited time, personnel, and resources.

The secret to finding and addressing issues before they become problems lies in robust and effective functional regression testing techniques with the right strategy for testing existing functionality and new or changed functionality with a combination of manual regression testing and automated regression testing at the right time and place. Right time and place are integral to the strategy, otherwise, you’d test everything all the time, everywhere, but obviously, who has the resources to do that. At XBOSoft, it’s our goal to help shorten your regression software testing cycles through effective test processes and best practices.

Regression Testing – The Need in Quality Assurance

Regression testing is an essential element of software quality assurance. It provides the assurance and confidence, that an application is ready for deployment. Most importantly, regression testing verifies that code changes do not re-introduce old defects, ensuring the quality of deployed software. Regression testing is a key component of most types of QA processes, covering desktop testing, web testing, and mobile testing. Many think that regression testing happens only at the end and only covers existing functionality, but regression testing is done throughout the software development lifecycle: from unit testing and integration testing to system and user acceptance testing. During unit and integration testing, regression testing can help catch defects early and thus significantly reduce the cost to resolve them. Unfortunately, Regression Testing in Agile seems to never happen due to the objective of velocity and “working software”. Most often, the definition of “done” does not include regression testing, but rather testing for that individual feature or function.

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Regression Pyramid

Regression Testing Example – Developing a Strategy

Designing a regression testing strategy is often overlooked, but it is still an important part of the QA process if the goal is to ultimately reduce total testing time without sacrificing software quality. Meeting this goal means starting with an evaluation of your current methodology: How are you testing? Are you designing your regression test cases effectively? And how is your regression test selection efficient and context-driven? What are your results? Where can you improve?

As an application matures, it builds an inventory of regression test cases. Although test automation may be able to reduce the time and effort required for a regression cycle, it typically is impractical to automate the entire suite and execute for every software change. But running only a portion of the entire test suite, such as unit-level regression tests, may not be sufficient to expose critical defects. An effective regression testing strategy, taking into consideration the available time and testing resources, should prioritize regression test cases of different types and methods to ensure that no important regression tests are missed. This also entails an automation strategy to automate where it makes sense while applying your manual regression testing where it adds the most value.

There are many facets at play when working with regression tests. The Regression Testing Pyramids capture these elements and how they are connected.

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Step 1

Regression Testing – When and Where Regression Testing Can Be Used

Whether regression testing in Agile or not should be employed throughout the software development life-cycle, providing valuable insight and feedback into code quality and functionality. Many think that regression testing only occurs at the end of development, but the term regression means returning to a previous state. As such, the intention of regression testing is to avoid defects or faults in the software from coming back after they were originally fixed or other parts were updated. This can happen throughout the development cycle with numerous types of testing, all with the objective of preventing previous problems from coming back. An overview of when and where regression testing can be used is given below:

Unit Testing

Check the functionality of individual modules by re-running previously passed tests for each modified module. Immediately after coding changes are complete for a single unit, a tester – typically the developer responsible for the code – re-runs all previously passed unit tests. In test-first and test-driven development approaches, automated unit tests can be built into the code, making unit regression testing very efficient in comparison to other types of testing.

System Integration Testing

Combine individual modules and test their interaction by re-running previously passed unit test and integration tests for all units that had changed, including targeted testing for modules that did not change. Testing scope would cover interface/API’s as well as back-end services This confirms the functionality of the complete software product and that it works as designed. Additional testing could include performance regression testing, accessibility, compatibility, and security.

User Acceptance Testing

Verifies that the software product meets the needs of the end-users. As part of the acceptance testing, re-running previously passed system tests along with GUI testing could be incorporated within the QA scope. Additional scripts can be run specifically from the end-user point of view either as part of manual regression testing (instead of automated regression testing), or targeted automated testing. For User Acceptance Testing, it’s critical to bring the end-users or product owners in to ensure that you’re testing exactly how they would use it. It may be backward, or totally different than what you thought.

Smoke Testing

Smoke testing is a spot check of high-priority regression tests that are executed after code changes are merged. The objective of smoke testing is to ensure that core functionality is acceptable before moving on to additional testing. At XBOSoft, we would recommend that smoke testing be an integral part of the QA process and employed every time software changes are pushed to the next cycle. Usually, smoke testing involves some manual regression tests but can be highly automated and part of continuous deployment initiatives.

Partial or Targeted Regression Tests

A partial regression testing approach identifies only certain types of tests to be run. Tests are often selected based on their priority and the functional area of the application. For example, an online retail business updates its payment processing application. In this case, the QA team may choose to conduct regression tests for the payment process, but exclude regression tests for other areas of the website, such as product search and side-by-side comparisons. In this approach, an established process for prioritizing regression test cases is helpful to managing the QA effort. This is probably where a strategy combined with a deep understanding of how the functionality of the software is connected and intertwined helps the most and is most often overlooked.

Complete Regression

With complete regression, all regression test cases within the suite are executed. This is generally costly and not always practical, especially for minor releases. In general, a full regression test suite may be necessary for major releases with significant code changes, major configuration changes such as an interface to a new platform, or after an update to an operating system. Unfortunately, many think that complete regression is the only regression that can sometimes take days, and even weeks to complete. However, with no regression strategy, testing everything becomes the default in order to feel confident in the software’s release.

Step 2

Regression Testing – Prioritization

These days with development cycles so short, we rarely have time for full regression, so we have to choose wisely where to spend our time and how to balance risk management and software quality. It’s not an easy task in developing a test strategy in terms of where to put one’s effort; manual testing, automated testing, exploratory testing, platform compatibility, etc., while achieving the level of confidence that the release is ‘defect-free’. Which test cases come first and when? Major release, minor release, patch release? At XBOSoft, we’ve developed a regression test strategy matrix to provide some guidance when addressing these challenging questions. By using a matrix approach, you’ll be able to categorize test cases and test more effectively.

The following prioritization strategy employs three steps and assumes four levels of priority: critical, high, medium, and low.

Step 2.1 – Assess Risks

Categorize “risk” according to the levels of low, medium, and high:

Low – Feature enhancement or feature related to main feature, but the failure of the test will not in delaying the release. Defects from this can be deferred or ignored.

Medium – Main feature, but failure of test will not impact release decision. Defects can be fixed after the release.

High – Main feature and failure of test will have a direct impact on the release decision. Related defects should be fixed prior to release and fixes need to be verified.

Step 2.2 – Assign Priority

Categorize “priority” according to the levels of low, medium, high, and critical:

Low – Feature enhancements that cover features that are not frequently used.

Medium – Related to main features, but no direct impact.

High – Main features related to business processes including function accessibility and availability.

Critical – Main business process that should be executed for any update in the same function or module. Exploratory testing should focus here.

Step 2.3 – Apply Results of Steps A & B to Prioritization of Test Cases

  1. Begin by selecting test cases that verify critical functionality and core features and link to those that pose the greatest risk of failure. This can be because the feature itself is critical to the system (high level of risk), or because the functionality is complex and prone to failure.
  2. Security tests dealing with customer data that should be kept secure and private, should be prioritized as high, or even critical.
  3. Test cases that have high code coverage or have had a high level of associated defects in the past can be assigned a high priority.
  4. Assign high priority to functional and regression testing cases that cover the most common use cases.
  5. In general, negative test cases can default to medium priority. Negative test cases verify handling of “negative” situations such as entry of a bad username or password in a login attempt.
  6. Generally, all validation tests can default to medium priority, including edge type cases, corner cases and special value cases.
  7. Depending on how well you know your application and understand the nature of the code changes, you may choose to treat non-functional and regression testing as low priority for regression testing.
  8. After all test cases have been prioritized, reassess those that cover areas of special risk, such as security, or test cases that verify compliance with regulations.
  9. As a “best practice”, periodically archive regression tests that no longer serve a purpose. These could be test cases that cover functionality which no longer exists in the application, or medium- and low-priority tests that have not revealed any defects in several rounds of regression testing.

You may think that this is too much trouble… But modern test management tools have lots of features that enable you to pick out, label, and extract test cases for targeted regression and prioritization.

In practice, per the graphic below, the colors between the cells would be contiguous shading and would not be that distinct. Red would be for tests that need to be executed with every release no matter what, whereas yellow, would only be for full regression.
regression testing strategy diagram

Step 3

Regression Testing – When to Incorporate Automation

In the past many thought that automated software testing was too expensive or difficult, especially given the cost of tools and the expertise needed to master them. However, in today’s shortened release cycles, test automation as an integral part of Devops is the new normal. In most cases, test automation is used as an effective means to reduce the overall costs of testing, while increasing test coverage and effectiveness, and shortening testing cycles. There are also various intangible benefits associated with automation such as reaching the market faster and improving tester moral (and productivity) through the elimination of tedious tasks. But there is an upfront investment in tooling and in gaining expertise to make it worthwhile. Many shops may buy an automation tool, only to let it sit there for years… Sound familiar?

Some may be sitting on the fence even today, deciding whether or not to automate software testing even after hearing of all the benefits of test automation. On the other hand, some blindly dive in a buy a test automation tool without carefully thinking through where and when to use test automation as an integral part of regression testing.

A successful regression testing strategy must contain a baseline understanding of test automation and where it fits best with the organization and its software. Key considerations are:

  • Clearly identify Test Automation Objectives
  • Review and assess regression testing tools for automation to determine what best fits the overall strategy and team skill sets.
  • Develop a Test Automation Strategy; Automation Test Case Design and Parameterization Guidelines, Test Automation Architecture, and Automation Framework Design Guidelines.
  • Validate the steps above by creating and executing some proof-of-concept automation scripts using the automation tool selected.

XBOSoft recommends the above include written guidelines on how to set up the test environment, deploy and execute scripts, maintain and extend the automation test scripts, and the incorporation of best practices in analysis of test results. Analyzing test results is probably the most difficult task in any type of testing, especially regression. Does anyone really bother with dashboards anymore?

Step 4

Regression Testing Tools – Open Source

One of the more difficult challenges that QA personnel may face is deciding what testing tool(s) to use and for what purpose. There are many variables that management must consider when selecting tools to QA software; budget, tester or team experience with test tools, and even business goals and strategies to name a few. Added to the decision matrix are the numerous software test tool vendors, each with their own broad set of features and functions, some of which you need now, or in the future, but many that you don’t need today, and perhaps may never need. That’s why, as discussed earlier, it’s important to clearly understand your objectives before going shopping. Don’t go to the grocery store with an empty stomach!

As a company that specializes in providing software testing services, we have learned a thing or two about automated regression testing tools. We generally chose open-source platforms over proprietary, not because of cost, but because of both their flexibility and capabilities. Depending on how they are implemented, they can be used for simple scenarios or scaled up to meet the needs of testing complex software with needed frameworks that ensure maintainability and extension requirements. Additionally, with a large number of developers dedicated to refining the software through 3rd party plug-ins, there are usually canned solutions either for problems you are encountering or additional functionality that you want to add to the base tool. In this environment, if there are issues with security and quality, they surface quickly and are rapidly addressed. Finally, open-source solutions have a supporting development community that serves as a valuable resource and are easily integrated with other tools via open interfaces as opposed to closed proprietary systems.

Whether you use open source or proprietary tools, we recommend building a regression framework from the ground up that addresses your specific needs and can be continuously adapted to ensure future growth and automation needs. The last thing you want is to have to re-boot your automation effort from scratch after discovering that your tool or your framework won’t suit your ongoing needs.

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Step 5

Regression Testing – Developing a Plan

To create an overall system-level regression test plan, begin by defining the entry and exit criteria and time boundary for each type of regression test. The time boundary is important because one type of testing may be dependent on another, and of course, with no time boundary, testing time can naturally expand.

  • Entry criteria may include that all software changes have passed unit testing, a green build has passed smoke and sanity testing, and the regression test suite is prepared.
  • Exit criteria may include that all priority test cases have been executed, all defects have been reported, all defects have either been resolved or deferred for future resolution, and the product owner or customer has signed off.

Identify the test cases or test types that will be part of the regression test suite. Keep in mind that you may have different regression test suites for different purposes. Include test cases for recently-changed code and for defects that were recently found and fixed. Exclude test cases for known defects that have not yet been resolved. Finally, automate test cases that are reusable for coverage of core features.

In the plan, be sure to allow time for exploratory testing as exploratory testing tends to find more issues than existing test cases and test automation. Also, allow time to conduct post-testing reporting and analysis. Otherwise, you’ll never be able to improve. Maintenance is also a critical activity as some tests become invalid while others may shift in priority or become broken-blocked and need updating. You should have a version control system for the regression tests themselves, whether they are automated or manual test cases.

Regression Testing – Reporting and Analysis

What information do the stakeholders need to make “quality” assessments and what information do you have readily available? The reporting should include whatever metrics are deemed necessary, no more, and no less. The last thing you want to do is produce reports that no one reads. Additionally, as your regression testing process changes and adapts over time, you may change your focus and therefore, use different metrics to support your focus. Some examples of questions that proper reporting can help answer:

  • Where to test more or less
  • What tests should be executed or not
  • What tests are effective
  • Should more tests be added
  • Where is QA spending the most time
  • What features or functions need refactoring
  • Overall product quality assessment

A key value in having a process in place for evaluating “product quality” is that it can provide warning signs when a change in regression testing techniques may be warranted.

Step 6

Regression Testing – Execution

Regression Testing in an Agile Environment

Testing features as you go in Agile without strategically aligned regression testing is a formula for disaster. But who has the time? And delaying testing into a subsequent sprint incurs technical debt while performing regression testing only limited testing increases the risk that defects will make it into production. The need for regression testing has only increased as software development life cycles have become compressed since even small modifications can impact the software’s behavior and interfacing 3rd party components. While some companies opt for unit testing and limited smoke testing to ensure usability and assume that code will remain more or less functional, this ignores the cascade effect that often occurs when alterations are made not just to the software itself, but in the way, the software behaves in conjunction with the surrounding context of platforms and peripheral plug-ins and interfaces.

At XBO, Agile regression testing starts with designing effective user stories with acceptance criteria and test cases that complement and verify the user story. These test cases must be ready to execute as soon as coding completes on a user story, to avoid becoming a bottleneck. With the “right” Agile test cases, we can evaluate where to expend the testing resources through “smart” regression test selection for targeted regression via test automation.

Below are some recommendations for optimizing your quality assurance resources with the limited time available in an Agile life cycle:

  • Create tasks in the sprint specifically for creating and grooming user stories.
  • Create a task in the sprint to create automation scripts for regression testing. These can be identified from the previous development iteration. Complete this task early in the sprint.
  • Ensure developers follows test-first practices by utilizing automated unit tests for new code.
  • Build time into the sprint for manual and exploratory testing of the user stories. This should be tested as development finishes each story.
  • Apply risk-based prioritization to manage the size of the regression test suite.
  • Use a dedicated server to run unit and integration tests for each build of the application.
  • Understand and track time for each type of task; user story creation, user story modifications, development, manual testing, automated testing suite creation, and test automation maintenance.
  • It is not necessary to run the entire regression suite for each build, but do run it at meaningful intervals.
  • Finally, make a clear definition of ‘done’ understood by all team members such that only user stories that have passed all regression tests should be designated as “done”.

Regression Testing Guiding Principles

It’s difficult to have “best practices” as what is best for one organization may not be best for another or prioritized for another, based on context. However, it is possible to develop guiding principles to lean on when making decisions and establishing your organization’s priorities and direction. Our regression testing approach is founded on a set of essential guiding principles including:

  • Automation feasibility — Can specific test processes be automated? Our test automation assessment (see below) helps you determine where best to apply automated regression testing and reduce the amount of manual testing while also focusing manual testing in the right places.
  • Continual alerts — Testing results are analyzed and tracked and your team is quickly alerted to quality degradations and defect counts between existing and new software build to prevent code degradation over time.
  • Organization — Our regression testing process systematically organizes and categorizes results to allow partial regression runs, and cases are combined into typical (and negative) user scenarios to empower acceptance testing.
  • New methodologies — To enhance usability and speed, XBOSoft has also developed a set of visual regression testing techniques that make it easier to identify issues and create effective testing solutions. We’re constantly evaluating new tools and methods, such as employing some of the newest AI-powered tools to understand where testing should be focused and how to minimize test automation maintenance costs.

XBOSoft – The Regression Testing Experts

Our regression testing services are designed around proven techniques that do more than identify defects. The combination of our needs-first approach, the right types of regression testing and regression test cases, open-source testing tools, and key best practices make it possible to increase delivery speed while improving the quality of your testing results. Reduce each regression testing cycle, while simultaneously improving the usability and functionality of your software deployments. Whether you are in the market for automated or manual regression testing, XBOSoft has a team ready to meet your needs.

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