Integration Tests with a Local Git Server

When we’re writing tests for our application, we need to ensure that the tests run on a reproducible environment to guarantee that the results match the expected values. This is a challenge when executing external commands that modify the state of an external resource, as the test conditions will be different the second time we execute the tests. The first strategy we’ll apply to handle this issue involves instantiating a local Git server by using a test helper function.

The setupGit() function

The test helper function setupGit() uses the git command to create a bare Git repository that works like an external Git service, such as GitLab or GitHub. A bare Git repository is a repository that contains only the Git data but no working directory, so it cannot be used to make local modifications to the code. This characteristic makes it well-suited to serve as a remote repository.

At a high level, the helper function will perform the following steps:

1. Creates a temporary directory.
2. Creates a bare Git repository on this temporary directory.
3. Initializes a Git repository on the target project directory.
4. Adds the bare Git repository as a remote repository in the empty Git repository in the target project directory.
5. Stages a file to commit.
6. Commits the changes to the Git repository.