Continuous Integration Process: How to Improve Software Quality and Reduce Risk

Guide to the Continuous Integration Process:

In the prior tutorial, we delivered an in-depth exploration of Shift left testing.

In the past, we delved into the intricacies of Continuous Delivery (CD) by investigating its details. CD ensures that production-ready software is continually available through consistent feedback cycles. The heart of the CD process is Continuous Integration (CI), the engine that powers Continuous Delivery.

To understand CI, we will break down the terms and derive a fundamental interpretation. “Continuous” denotes something constant or repeated, while “integration” means to bring together or incorporate into a whole. Thus, CI is a procedure where merging occurs regularly.

Next, we need to address this question: What is being merged and where is this place?

Given that CD expands the concept of CI, the answer seems straightforward, correct?

The “what” being merged is code, and the “where” is a repository or version control system.

Thus, Continuous integration is a procedure that allows for frequent code check-ins within a repository.

As mentioned in the previous discussion, tests are executed instantly to catch any errors whenever a code check-in takes place, establishing the necessary, feedback cycles for Continuous Delivery.

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Decoding the Continuous Integration Process

Let’s return to the CD pipeline diagram that we examined earlier to focus on the highlighted area. This will aid our understanding of the CI process.

While the CI process may appear to center on development aspects, it is essential for QA engineers to understand it holistically and adjust accordingly.

Before delving any deeper, orienting ourselves with the following terminology is crucial:

• Source Code or version control system houses the entire code base required for a project or a feature.
• Mainline: This refers to the most current state of the code in a version control/source code system.
• Local Copy: In an IDE similar to Eclipse, the project’s codebase may be imported into a specific local machine location referred to as the “local copy”.
• Check Out: Often, developers start their work by importing the most recent source code into the local copy. This process is known as “checking out”.

Consider a situation where two or three development engineers are utilizing CI while working on a feature.

The sequence of events typically involves:

1) The developer codes the new feature on the local copy.
2) After completing the code, automated unit tests are created to test this code.
3) A local build is performed to verify that the recent code doesn’t create issues.
4) Once the build succeeds, the developer verifies whether there have been new check-ins from peers.
5) If there are new updates, the developer must integrate those changes into the local copy to keep it current.
6) The syncing process with the mainline might lead to conflicts as local copies merge.
7) Any conflicts are resolved to align the changes with the mainline code.
8) After step 7, the code changes are ready to be committed. This action is known as “code commit”.
9) After the commit, another build that corresponds to the source code (mainline) is run on the integration system.
10) This build is now prepared to be used by subsequent stages.

Tools for Continuous Integration

The selection of CI tools depends on an organization’s preferences.

Common choices include Hudson, CruiseControl, and Jenkins, among other tools that offer similar features alongside their own unique offerings.

Choosing a CI tool is influenced by various factors, such as:

• Integration with configuration management tools
• User-friendly and customizable reporting
• Integration with automation tools, and so on.

=> Find a comprehensive list of CI tools and their features here

The Advantages of Continuous Integration

#1) Early Error Detection: A build failure occurs when there is an error in the local copy or uncommitted code, forcing the developer to correct the issue before progressing. This method also benefits QA teams as they predominantly work with stable builds.

#2) Lesser Bug Accumulation: While bugs are inevitable, CI considerably diminishes their accumulation. With effective automation, bugs can be discovered and addressed promptly, thus minimizing risks.

#3) The Gateway to Continuous Delivery: CI automates build processes, sanity checks, and other tests, reducing manual intervention. This sets a robust foundation for a successful continuous delivery.

#4) Increased Transparency: CI elevates the transparency in development and QA proceedings. It provides clear indications about failing tests, failure causes, defects, and more, fostering data-driven decisions to streamline efficiency.

#5) Cost Efficiency: Given the above points about timely error detection, reduced bug accumulation, increased automation, and amplified transparency across the system, cost optimization becomes apparent.

CI with a QA Lens

This is a logical progression of our earlier discussion. A few critical factors must be considered when using CI for testing.

#1) Initial Tests: Post a code commit, automated tests should be triggered to execute smoke or sanity checks, confirming that the build is ready for QA.

#2) Automation Framework: To truly maintain the ideals of CI, each QA team should commit to building a test automation framework. This framework should automatically trigger tests to detect feature-specific shortcomings and shed light on the need to enhance the framework (for present and future tests).

#3) Parallel Testing using Automation: A robust automation framework allows parallel testing and the duplication of production environments with varied configurations. It also offers better test coverage and lessens the likelihood of bugs escaping detections.

#4) Automation across Different Types of Tests: Test automation should incorporate different kinds of tests, including functional and non-functional tests (for instance, stress, load, performance, regression, database, acceptance, etc.).

#5) Automated Bug Logging: CI systems can also automate bug logging. Specific errors can be examined in logs, and when encountered, a bug is automatically logged. An example of this automated bug logging could be for NullPointer exceptions observed in a server trace log.

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Best Practices for Implementing CI

The goal of Continuous Integration is to drastically minimize errors during software development via feedback mechanisms, automation and prompt rectification of bugs.

While achieving this may seem ambitious, by adhering to these best practices of continuous integration, it is achievable:

#1) Shared Code Repository: With Agile gaining prevalence, having a shared repository that records the changes across multiple developers working on the same or different features of a product is crucial. Tools for version or source control aid in creating various development streams and ensure that all the necessary artifacts for a complete build, such as libraries, properties, environment variables, test scripts, etc., are stored in one place.

#2) Auto-Trigger Builds via CLI: Builds should be automated to the extent that they can be initiated through a CLI. For instance, making use of ANT or Maven to initiate builds enables loading required assets from a repository (online or local), compiling and running the build with a straightforward command. The build tool should only download the resources that are necessary. Particularly in large builds where specific artifacts might have already been downloaded during a previous build. Additionally, tests should be part of the build to identify any glaring bugs at the onset.

#3) Regular Code Commits: This system efficiently catches code conflicts, even when multiple developers are involved. Before committing, each developer must update their local copy. Doing so daily or as frequently as feasible ensures that the local copy stays current with the mainline. The more updated the local copy, the lesser conflicts arise, leading to increased stability.

#4) Quick Build Time: Long build times defeat the purpose of Continuous Integration as they obstruct continuous feedback. Furthermore, frequent code commits become a greater challenge. To address this, it is advised to implement staged builds, breaking the build pipeline into smaller segments that can be executed in parallel.

#5) Execute Mainline Build on Integration Machine: During the Continuous Integration process, a second build regarding the mainline code is executed on the integration machine. This build helps expose bugs that may surface in specific environments but not in others. It also reveals human errors, such as a failure to sync code with the mainline. It is only after the build is successfully executed on the integration machine that the commit can be confirmed.

#6) Duplicate the Production System: To tackle environment-specific defects, it is good practice to have a test environment that closely matches the production system. This guarantees major discrepancies and risks are identified before being introduced to the production environment.

#7) Automate Deployment: Setting up the necessary runtime environments for testing should be automated for diverse types of testing in a CI model.

#8) Publish Build Locations: With frequent builds, notifying all stakeholders about the location of the latest build is critical. A shared repository for published builds should be accessible to everyone involved. In addition, build and initial sanity results should be published, providing visibility into integrations or fixes.

Conclusion

The application of CI in testing organizations is invaluable due to its capabilities in automation.

As demonstrated above, CI minimizes testing effort and enhances precision, which is fundamental for the entire Continuous Delivery process.

Continuous Delivery and Continuous Integration are critical elements of the Agile methodology. Embracing these practices advances organizations towards effectively responding to rapidly evolving and dynamic market demands.

We welcome any additional best practices or recommendations for continuous integration.

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