Continuous Integration (CI) Testing Best Practices in 2023

Continuous Integration (CI) Testing Best Practices in 2023

Continuous Integration (CI) is an essential practice in modern software development that enables developers to continuously integrate their code changes into a shared repository. Through automated building and testing processes, CI ensures that every code change is tested thoroughly, preventing integration issues and improving software quality.

In this article, we will explore the best practices for effective Continuous Integration testing.

#1 Think Security First

Data breaches and vulnerabilities wreak havoc on businesses, which only emphasizes the importance of security. One area that often becomes a prime target for attackers is the continuous integration and continuous delivery (CI/CD) pipeline, as this system provides access to valuable codebase and deployment credentials, making it a potential entry point for malicious activities. 

It’s common for sensitive credentials to be stored in private repositories for automation purposes. So, to strengthen security, it’s crucial to consider isolating your CI/CD systems within secure internal networks. By adhering to the principle of least privilege, you can limit exposure to risks. 

Additionally, implementing virtual private networks (VPNs), robust two-factor authentication, and identity and access management solutions can provide an extra layer of protection. For example, containerizing your agents and placing them on secure networks can enhance security measures.

Last but not least, it’s vital to integrate security into the development process right from the beginning until the project’s completion. This approach is known as “DevSecOps,” wherein security considerations are seamlessly woven into the entire development lifecycle.

#2 Use a Microservices Architecture

If your project is built on a monolith architecture, restructuring your current applications can present significant challenges. However, the benefits outweigh the disadvantages, as a microservices architecture enables you to add new functionalities without redesigning your system’s complete structure.

You can also opt for an incremental approach where you retain your mission-critical systems and gradually integrate the new architecture alongside them. This way, you can steadily replace the old architecture with the new one, ensuring a smooth and manageable transition process.

EaaS platforms like Bunnyshell automate the deployment of full-stack environments on Kubernetes, containing all necessary microservices for CI testing. This automation streamlines the setup process, ensuring consistent, repeatable testing environments crucial for reliable CI workflows.

#3 Commit Early, Often, and Minimize Branching

A fundamental principle of CI/CD is to regularly integrate changes into the primary shared repository at the earliest opportunity. This approach prevents costly integration issues that may arise when multiple developers try to merge significant, divergent, and conflicting changes into the main branch just before a release. To ensure a smooth and efficient development process, CI/CD systems are typically configured to monitor and test changes committed to only one or a few branches, promoting a continuous and incremental integration approach and thus reducing the risk of integration challenges and maintaining a more stable and collaborative development environment.

The main objective of minimizing or eliminating branching is optimizing the development process and reducing the time spent on version control. By doing so, you can allocate more time for actual development work.

To fully leverage GitOps, you should commit changes regularly, ideally at least once daily. These changes can be committed directly to the main branch or by merging them from their local branches. This approach ensures that integration is handled in smaller, more manageable increments, avoiding the significant integration pain and potential rework that arises when attempting to merge multiple branches into the main branch just before a release.

This approach allows you to streamline your workflows and enhance collaboration, leading to more efficient and productive development cycles.

#4 Only One Way to Deploy to Production

CI/CD is effective in enhancing development practices and code quality due in part to the tooling that helps enforce testing and deployment best practices. Each change must adhere to your organization’s established standards and procedures to progress through the CI/CD pipelines. Failures in the pipeline are immediately visible, halting the advancement of the affected release to subsequent stages. This gatekeeping mechanism ensures that critical environments are protected from untrusted code.

To fully reap these benefits, it’s essential to maintain discipline and ensure that every change to the production environment follows the CI/CD pipeline. The pipeline should be the sole mechanism for introducing code into the production environment. This can occur automatically through continuous deployment practices after successful testing or via manual promotion of thoroughly tested changes, approved and made available by the CI/CD system. By adhering to this approach, you can establish a reliable and controlled process for deploying code to production, resulting in higher code quality and reduced risk of errors.

#5 Keep Your Production and Test Environments as Similar as Possible

CI/CD pipelines facilitate the progression of changes through various test suites and deployment environments. Changes that meet the requirements of one stage are either automatically deployed or queued for manual deployment into more restrictive environments. The initial stages serve to validate the feasibility of continuing to test and push the changes closer to production.

To ensure accurate testing that reflects production behavior, it’s crucial to closely replicate the production environment in the testing environments, especially in later stages. When staging and production environments significantly differ, problematic changes may be released without being identified as faulty during testing. The more discrepancies between the live environment and the testing environment, the less reliable the tests become in predicting the code’s performance upon release. Thus, striving to replicate the production environment as closely as possible in testing environments is essential to ensure effective and accurate testing throughout the CI/CD pipeline.

#6 Have a Clear Plan on What to Test, When, and Where

All tests can be categorized into two kinds: lightweight tests and heavyweight tests.

Regarding timing, in a Sprint that spans over two weeks, it’s advisable to merge development changes to the staging branch three days before the Sprint’s end. This timeframe allows sufficient time to conduct testing, address critical bugs, and prepare the environment for a demo. The staging code can be manually tested, and if no critical bugs are found, it can be merged into the release branch. Once merged into the release branch, the code can be automatically deployed to the production environment.

Ensuring feature branches are up-to-date with the latest development changes is essential before merging feature branches into the main development branch. Neglecting this step could lead to a situation where the feature branch appears green, and the development branch is also green, but the merge result is buggy. To maintain consistent quality, merging the feature branch into development and conducting testing is crucial. This testing process can be automated in the CI/CD pipeline, and the merge should only be built and pushed to the repository if the test results are positive (i.e., the test is green). This ensures the development branch remains stable even after the feature branch merge.

Also, keep in mind that different parts of your test suite will naturally have varying speeds. As the CI/CD system acts as a gateway for all changes entering your system, early detection of failures becomes crucial to minimize resources spent on problematic builds. Make sure to prioritize and execute your fastest tests first. By validating the build with smaller, quick-running tests, you can efficiently identify issues before proceeding to more complex and time-consuming tests.

Last but not least, if your setup doesn’t allow for isolated testing environments, test locally first before committing to a shared repository to avoid blocking other team members. Although a local development environment will probably not be able to run the entire test suite in a production-like environment, it can at least help you confirm that the changes you are making pass basic tests and are worth trying to integrate into the larger codebase.

#7 Avoid Parallel Work

Avoid any practices that lead to multiple compilations of source code. The compilation process should be executed only once, even if additional steps, such as packaging or bundling, are required before software distribution. Instead, focus on distributing the compiled binaries. The main purpose of a CI/CD pipeline is to build confidence in your changes and minimize the chance of unexpected impact.

Likewise, you should version and publish the final artifact to Git at each iteration, as this ensures that the build remains consistent and does not deviate from its original state when the repository is later pulled or accessed.

#8 Use Automation Whenever Possible

When transitioning from manual to automated processes, it can be challenging to determine which tasks should be automated first. While adopting an incremental approach may seem appealing, it can also pose difficulties. To streamline the process, specific tasks should be prioritized for automation.

A logical starting point is automating the code compilation process as it reduces the risk of human errors. Automated smoke tests are also beneficial, especially when developers commit daily. Unit testing is often prioritized next to ease the burden on developers.

Consequently, functional testing can be automated, followed by user interface testing. Functional tests typically require fewer script revisions than UI tests, which are more susceptible to frequent changes. To prioritize automation effectively, it’s important to consider potential dependencies and their impact on the overall workflow.

#9 Use On-Demand Testing Environments

Consider running tests within containers, as this can minimize the number of variables and discrepancies between the development and production environments. This, in turn, enhances the efficiency of your CI/CD cycle and adds agility to your testing process.

Using container-based ephemeral testing environments can significantly benefit your QA team. Rather than pulling a build from a CI server and installing it in a separate testing environment, tests can be executed directly against an isolated application environment without affecting other ongoing tests. This approach saves time and reduces the potential for errors.

Creating containers is a straightforward process without needing separate installation or configuration, making it convenient to set up testing environments. Additionally, containers can be easily destroyed when no longer needed, simplifying the cleanup process.

Adopting container-based testing can streamline your testing workflows, improve consistency between environments, and enhance the overall efficiency of your development and testing processes.

Environment-as-a-service platforms like Bunnyshell facilitate the creation and deployment of container-based, isolated testing environments on Kubernetes in response to pull requests. This allows for immediate, automated testing of changes in a controlled, replicable environment, enhancing the efficiency and reliability of the development process.

Want to explore the benefits of ephemeral testing environments? Why don’t you give Bunnyshell a try? Read our comprehensive docs to learn more, or register for a free account and start your journey toward simplified software development.