Testing: How to set up an initial repository with some branches to operate on?

[DennisTheMenace780]

I've been chipping away at trying to better understand how to set up the initial state of a test within my application. The initial setup that I need is fairly minimal:

1. Set up a git repository for my tests to run on.
2. Create a few branches.
3. Create a file on one of the branches.

I think that from this setup I can get further on my own. I've looked at the common_test.go package and there seems to be some helpful structs and functions here, but they depend on fixtures from go-get/fixtures, which seem to only pull remote repositories.

Pulling something remote is not necessarily what I need to do, so that seems to be out-of-scope.

I suspect I need to do something with the billy filesystem interface, but I haven't quite figured out how to leverage this to do what I need yet.

So far I have something, but it doesn't work as expected. For example, when I create all of the branches on the repo, I am unable to iterate over them with ForEach(), at all. In fact, I don't even think the function passed to ForEach() gets called. What I find strange, though, is if I do something like b, err := repo.Branch("refs/heads/JOB-62131/JOB-76475/add-location-timers-to-fms") then I can get that branch back without error.

func TestCommonSuiteExample(t *testing.T) {
	repo, _ := git.Init(memory.NewStorage(), memfs.New())
	branchNames := []string{
		"refs/heads/JOB-62131/JOB-76475/add-location-timers-to-fms",
		"refs/heads/JOB-62131/JOB-76477/store-feature-enablement",
		"refs/heads/JOB-62131/JOB-77400/show-modal-dialogue-on-disablement",
	}

	for _, b := range branchNames {
		opts := &config.Branch{Name: b}
		err := repo.CreateBranch(opts)
		if err != nil {
			log.Fatal(err)
		}
	}
	branches, _ := repo.Branches()

        // Branches don't seem to get iterated over here, not sure why.
	branches.ForEach(func(ref *plumbing.Reference) error {
		fmt.Print(ref.Name().IsBranch()) 
		return nil
	})
}

Any help would be appreciated! I've spent a fair amount of time looking through various tests for examples that might suite what I need, but I haven't been able to put the right pieces together.