What is build and passing button in github?

Question

I guess those something related to project deployment tools. Actually what are those, how to add those and what is the benefit of those?

Edit 1
Is there any billing issue(payment) with those or those are free?

Answer 1

They're known as Code Repository Badges, and detail various aspects of the general stability of the repository. There are a number of badges available, but the most common are:

• build: passing: Indicates that the project's tests are all passing. This is usually set up through Travis-CI integration.
• coverage: How much of the project is tested. 75% of the code in your image has been through passing unit tests.
• dependenices: How many dependencies the repository has on other repositories in order to run
• devDependencies: How many dependencies the repository has on other repositories in order to develop

Answer 2

These are something known as Code Repository Badges.

To quote an online resource:

As people who are passionate about writing great code we display "badges" in our code repositories to signal to fellow developers that we set ourselves high standards for the code we write, think of them as the software-equivalent of the brand on your jeans or other reliable product.

In short, it's a way to say that "hey, look, my GitHub project has a high standard!". The link above actually goes into a fair bit of detail on the different badges, but let me just point out two common ones shown in your picture:

1. "Build passing"

This makes use of continuous integration tools like Travis CI which will help to build and test your code when you push code onto a GitHub repository (given that you have set up Travis CI for that repository).

Using this can ensure that no breaking changes get merged into your project, and also prevents wasting reviewers' time and effort on pull requests that are not "working".

2. "Coverage"

This measures how much code in your GitHub project is actually tested. It makes use of tools like Codecov, again premised on the fact that you have set up such tools for your repository.

Using this can remind contributors to write proper tests for the code, so that any potential bugs in the code can be detected.

As you can see, the badges help to ensure that your project maintains a certain standard, which can improve your project quality, and even attract people to work on your project (e.g. in the case of open-source software hosted on GitHub).