As a backend developer, you are responsible for ensuring that the application you are working on is stable and bug-free. This is especially important if you are working on a continuous integration (CI) server, as every code change needs to be verified before it is deployed to production.
Testing your code is critical to avoid breaking production, but it can be time-consuming and difficult to get right. In this article, we will discuss how to set up a CI server to automatically test your code and give you feedback on any errors. We will also show you how to use a tool called Jenkins to automate your testing process.
Continuous integration is the practice of merging all developer working copies with a shared mainline several times a day. CI is a critical part of the modern software development process. It helps developers avoid the "integration hell" that can happen when code from different developers needs to be merged together.
CI also has the added benefit of making it easier to find and fix bugs. By merging code more frequently, you are less likely to have large code changes that can introduce bugs. And, if a bug does enter the system, it is easier to identify which code change introduced the bug. This can save hours or even days of development time.
There are many different CI servers available, but we will focus on setting up Jenkins. Jenkins is a popular open-source CI server that is easy to set up and use.
Before we get started, you will need to install Jenkins on your server. You can find instructions for doing this on the Jenkins website.
Once Jenkins is installed, you will need to create a new job. To do this, go to the Jenkins dashboard and click on "Create New Job".
Give your job a name and select "Build a free-style software project". Then, click "OK".
On the next screen, you will need to configure your job. In the "Source Code Management" section, select the "Git" option. Then, enter the URL of your Git repository in the "Repository URL" field.
In the "Build Triggers" section, select the "Poll SCM" option. This will tell Jenkins to check your Git repository for changes every few minutes. You can also choose to trigger a build manually if you prefer.
In the "Build" section, select the "Execute Shell" option. This will allow you to run shell commands as part of your build process.
In the "Post-build Actions" section, select the "Publish JUnit test result report" option. This will publish the results of your tests to Jenkins so that you can view them later.
Click "Save" to save your job configuration.
Now that your CI server is set up, you need to write some tests. Tests are written in a language called JUnit, which is a Java-based testing framework.
Here is a simple test that verifies that the add method of a calculator class returns the correct result:
public void testAdd() {
Calculator calculator = new Calculator();
int result = calculator.add(1, 2);
assertEquals(3, result);
}
This test will fail if the add method does not return the correct result.
You can learn more about writing tests by reading the JUnit documentation.
Once you have written some tests, you need to run them. To do this, go to the Jenkins dashboard and click on the name of your job.
On the job page, click on the "Build Now" link. This will trigger a build of your job, which will run your tests.
Once the build has completed, you can view the results by clicking on the "Build History" link. This will show you a list of all the builds that have been run.
Click on the most recent build to view the details. In the "Build Output" section, you will see the results of your tests.
In this article, we have discussed how to set up a CI server to automatically test your code. We have also shown you how to write and run tests using the JUnit testing framework.
By setting up a CI server, you can save time and reduce the number of bugs in your code.