What Is CI/CD Testing?
Continuous Integration and Continuous Delivery (CI/CD) comprises principles, practices, and technology that enables DevOps teams to push software from development to production in an automated, repeatable manner.
One of the key tenets of CI/CD is that the pipeline should produce high quality deliverables that provide value to customers. This is where CI/CD testing comes in—it is a set of gates that validate the quality of software releases. CI/CD testing aims to ensure that software versions are promoted in the pipeline only if they meet functional requirements, are stable, and are free of bugs and security issues.
CI/CD testing is typically automated, allowing it to be fully integrated with the CI/CD pipeline. There is still a place for manual testing in modern CI/CD processes, but it must be carefully managed to avoid slowing down the pipeline.
CI/CD Testing: Manual vs Automated Testing
Automation is the key to building a CI/CD pipeline with development, operations, and testing teams collaborating in a unified release process. However, manual testing remains a ubiquitous, time-consuming process throughout the software development lifecycle. Some tests will always require manual intervention, but many processes can be automated to support iterative releases.
Automated testing speeds up feedback loops by continuously checking code. It is important to automate as much of the testing process as possible, including system and unit tests. Shorter release cycles make identifying and addressing bugs easier, while slow builds can derail projects. Organizations should automate everything they can because slower manual processes create bottlenecks slowing down the whole pipeline.
Automation also helps break down the testing stage into manageable components in test suites. Certain tools can perform regression tests to ensure the application functions correctly after each change. Some tools support parallel testing to speed up the testing process.
Environment management is a frequently overlooked aspect of the development cycle, with many teams spending valuable time implementing manually. Test environments must mimic the actual production environment to ensure the application performs as expected. Fine-tuning environments to reflect the real world can be time-consuming. Testers can automate the provisioning of test environments to save time and make the process more manageable.
What Is Continuous Testing?
Continuous testing enables teams to incorporate automated feedback at different phases of the software development life cycle (SDLC). It helps shift testing left to ensure teams get feedback earlier in the SDLC cycle when it is easier and more affordable to remediate issues.
Continuous testing is a key component of continuous integration / continuous delivery/deployment (CI/CD) pipelines. It provides timely feedback to help improve code quality, accelerate SDLC timelines, avoid bottlenecks, and expedite DevOps processes.
Typically, continuous testing involves using automated tools that help minimize the human error often involved in manual testing. It also helps shift testing left, ensuring the pipeline remains efficient while introducing more validation into the process from start to finish.
You can implement continuous testing by loading predefined quality assurance (QA) scripts to automated tools that test all development stages. Automated scripts help sequentially validate source code efficiencies, providing feedback immediately to the relevant teams.
3 Reasons Test Automation Is Essential for CI/CD Pipelines
There are multiple reasons why you cannot build a true CI/CD pipeline without test automation. Below are three of the most important reasons.
Related content: Read our guide to the CI/CD pipeline
1. Test Automation Supports High Development Velocity
Modern CI/CD pipelines facilitate very frequent releases, but this can make it difficult to deal with bugs. There is a major risk that builds, polluted with quality issues, will be promoted to production environments before there is time to resolve the issues. This can not only create issues in production, but can also make it more difficult to maintain and debug the code in the future.
The only way to verify quality in the pipeline is to enforce mandatory, automated tests and fix the discovered issues before releasing a new feature. If DevOps teams do not standardize on automated testing, they will constantly be surprised by issues and busy with ad hoc solutions. In the end, a lack of consistent testing will not save time but actually slow down the pipeline.
2. Test Automation Enables Shift Left Testing
The CI/CD pipeline is a continuous, rapid flow of changes to a software project, which shortens the overall test cycle. Shifting testing left moves testing earlier in the SDLC, emphasizing the importance of finding bugs during planning phases or early development phases. Bugs found early in the SDLC are much less complex to fix and have a much lower cost.
Another advantage is that developers can fix bugs as part of their regular development work, while still in the context of a specific software component. This is far more efficient than being called into urgent maintenance work on components they are no longer working on, or were developed by others, interrupting their current line of work.
3. Test Automation Enables Automated Regression Testing
One of the best practices for a CI/CD pipeline is that the code should be in a central repository where developers can create pull requests and push code to the main branch to implement features or bug fixes. A central repository keeps your code up to date, keeps builds in a maintainable format, and logs all changes to identify version differences.
When you have version control in place, and the latest build does not work as expected, instead of trying to find the bug, you can simply roll back to the previous version. However, this approach can backfire because you did not identify the true root cause of the issue. It will also revert many positive changes you made in the last build.
A better approach is to implement automated regression testing that immediately notifies you, at the build stage, when code changes created a regression in the software. This lets you identify bugs when they happen and fix them, while you are still working on the change that resulted in the bug.
Best Practices for CI/CD Pipeline Testing
Classify Tests According to Effort
Some tests are only effective when performed manually—it may not be efficient to automate all test cases. Classify test cases into manual and automated. Test cases that are run frequently, require special skills, and have repetitive actions are more suitable for automation. This concept is known as the testing pyramid – the easier it is to create tests, the more you should create of them.
It is also useful to classify automated tests by difficulty and importance (for example, whether the test is critical for user functionality) to prioritize your work.
Set up Multiple Tests in Parallel
Running multiple tests in parallel reduces execution time of the test suite. This is very important in CI/CD pipelines because developers need fast feedback. You can use parallelism to:
- Test multiple modules and applications
- Test applications on multiple platforms and browsers
- Distribute test workloads across multiple physical machines
Create Test Environments On-demand
The traditional way to test an application before going into production is to use a ready-made staging environment. Having only one staging environment is a major drawback, as developers must either test all features at once or queue and “reserve” the staging environment just for a specific test.
To resolve this issue, some organizations create several test environments to allow multiple developers to test features in parallel. This technique is also not ideal, because the number of parallel tests is limited to the number of environments, and all test environments consume resources even if they are not used. It also means every test environment needs to be cleaned and updated between tests, which creates extra overhead for teams.
A cloud-based architecture makes it possible to create test environments on demand. The pipeline workflow can generate a dedicated test environment whenever a developer creates a pull request. The environment will be suitable to the software being modified, and will contain the content of the latest pull request.
Benefits of dynamic test environments include:
- Each developer can test independently without competing with other developers.
- Test environment resources are only paid for when used.
- At the end of the test, the test environment is destroyed, so there is nothing to maintain or clean up.
- Ability to scale up to support more tests when needed.
Optimize Tests for Fast Execution
Test suits must be quick to execute to enable integration into the delivery pipeline. Tests shouldn’t take longer than the compilation process – between five and fifteen minutes. They should be simple because complex tests take longer to set up and often address redundant issues.
Fast tests let developers know their newly committed features don’t have regressions, allowing them to progress to the next pipeline step. If a test takes two hours, for example, this creates an unacceptable bottleneck because developers cannot afford to wait so long after a commit. Another effect of slow testing is that developers switch to other tasks, so the commit is no longer fresh in their minds when they return to it.
Most time wasted on slow tests results from inefficient practices and configurations. Code often waits for events to happen – it is better to use event-driven testing to avoid waiting. Creating test data can also be time-consuming – the data creation code should be centrally stored and reused.
Related content: Read our guide to CI/CD best practices
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