Continuous Integration usually refers to integrating, building, and testing code within the development environment. Continuous Delivery builds on this, dealing with the final stages required for production deployment.
The Dev Side of DevOps Four processes provide clarity and insight into the world of development within DevOps. They are the buzz words that light up professional circles, but the devil in the details is most often ambiguous. The four processes are:
Continuous Integration
Continuous Testing
Continuous Delivery
Continuous Deployment
Continuous Integration is performed by tools, while Continuous Delivery is performed with the help of tools & team but the Continuous Testing process requires the involvement of tools, teams, individuals, and services.
Continuous integration (CI) Continuous Integration is a process where developers integrate their code with the source code repository on a regular basis, multiple times a day (if feasible). Whenever they integrate, the entire mainline is built, and other activities such as unit testing and checking the code-quality also take place. For example, if a project has four developers, and let’s say that each developer integrates his code three times a day, then there will be twelve integrations every day. This translates to twelve builds of the mainline, twelve sets of unit tests and the code quality checks that run for twelve times. The main goal of continuous integration is to create a consistent way to automatically build and test applications. It ensures that a change from one developer is suitable for use in the entire code base. Through continuous integration, developers can solve problems they face when writing, integrating, unit testing and delivering software applications to end-users.
Integrating code frequently and running builds every time catches defects sooner, rather than later. If something goes wrong earlier in the process, a rollback generally only involves a few hundred lines as opposed to a whole restructuring. When each of the integrations is successfully built, unit tested, and code-quality checked, the work goes into the next stage in the delivery pipeline called continuous testing.
Continuous Delivery (CD)
Continuous delivery involves a set of processes that helps developers build a refined software version by continuously getting feedback from users and implementing necessary fixes. It entails all activities in continuous integration and continuous testing, coupled with human-influenced decisions that improve the quality of software. Continuous delivery requires a staging area where code changes can be verified and reviewed manually. Upon verification, the software can be released for production. In other words, the build is sent to a production environment for user acceptance testing (UAT) before deployment.
Continuous Deployment (CD) In continuous deployment (also known as CD), all changes made by the developing teams are automatically passed through the pipeline, and upon passing test stages, the updated product is pushed to production for release. Continuous deployment does not require manual verification because automated testing is incorporated throughout the development and release processes. As such, most attributes of the application rely heavily on the quality of the software test suite. Continuous deployment allows development teams to have multiple app deployments on any day without worrying about a major release.
The purpose of CI/CD? CI/CD puts together all code changes into a single repository and runs automated tests. As such, the product is fully developed and ready for deployment throughout all phases. One of the major benefits of executing CI/CD is that it enables quicker, efficient, and automatic product updates. It also mitigates defects in products, thus ensuring higher customer satisfaction upon release.
Continuous Testing (CT) It is a way to boost, speed-up, and support the DevOps CI/CD pipelines. It includes the practices, processes, and tools of testing early, testing often, testing everywhere, and automation. the aim of continuous testing is to “obtain immediate feedback on the business risks associated with a software release candidate.” Continuous Testing is the process in which the code integrations that are built during the Continuous Integration process get sent into a pipeline of various tests (integration, system, performance, regression, and user acceptance to name a few) and the tests get executed automatically – with zero human involvement.
let’s look at how continuous testing fits in throughout the DevOps pipeline. #1Unit testing aims at getting fast feedback on new code. Well-planned and executed unit testing helps ensure that the code is well-structured, with isolated components that are easier to debug and fix later on. #2 Integration Testing happens when the software components are merged into the shared pipeline, in order to ensure that the build remains stable as new code is introduced. #3 Automated End-to-End and Regression Testing are performed when the code is finalized, by packaging and deploying it across different servers and resources to ensure that the application works in an environment that imitates production. #4 Production Testing shifts testing right, extending it after the application is released. Testing in production serves to locate issues before they cause major problems for customers. #5 Exploratory and Live Testing is when automated testing is replaced by manual, or live, interactive testing, that attempts to break an application or find unexpected results.
Whenever developers integrate their code, it runs through the Continuous Integration cycle discussed above. If the process is successful, the binary that is built out of the Continuous Integration process will be tested automatically. As illustrated in Figure , the binary is automatically run through integration testing. If successful, system testing follows. If that succeeds, regression testing follows. If regression succeeds, automatic user acceptance tests (UAT) are executed. Likewise, you can add, delete, or modify any tests that you need in this pipeline.
The process of Continuous Testing ensures that once the code is integrated, it gets tested automatically.
The Complete Process Of CI, CT, And CD
Continuous Integration is the process that integrates the changes made to the code or new functionalities developed by the developer to the main software product. This process indeed makes the continuous testing process very critical.
A build is created by validating these changes. The automated tests are then performed on this build. This complete process gets extended through the Continuous Delivery process. The testing process ensures that the changes can be delivered. Along with continuous testing, continuous delivery is also an automated process. Developers can release the application or changes with just one click. The concept of moving the testing earlier in the lifecycle or doing it frequently is also called shifting left.