Move test package inside the git package

It is not being used by other packages so it should belong to `git` package.

pkg/git/test/helpers.go

@@ -0,0 +1,94 @@
+package test
+
+import (
+	"fmt"
+	"git-get/pkg/run"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// TempDir creates a temporary directory inside the parent dir.
+// If parent is empty, it will use a system default temp dir (usually /tmp).
+func TempDir(t *testing.T, parent string) string {
+	dir, err := ioutil.TempDir(parent, "git-get-repo-")
+	checkFatal(t, err)
+
+	// Automatically remove temp dir when the test is over.
+	t.Cleanup(func() {
+		err := os.RemoveAll(dir)
+		if err != nil {
+			t.Errorf("failed removing test repo %s", dir)
+		}
+	})
+
+	return dir
+}
+
+func (r *Repo) init() {
+	err := run.Git("init", "--quiet", r.path).AndShutUp()
+	checkFatal(r.t, err)
+}
+
+// writeFile writes the content string into a file. If file doesn't exists, it will create it.
+func (r *Repo) writeFile(filename string, content string) {
+	path := filepath.Join(r.path, filename)
+
+	file, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	checkFatal(r.t, err)
+
+	_, err = file.Write([]byte(content))
+	checkFatal(r.t, err)
+}
+
+func (r *Repo) stageFile(path string) {
+	err := run.Git("add", path).OnRepo(r.path).AndShutUp()
+	checkFatal(r.t, err)
+}
+
+func (r *Repo) commit(msg string) {
+	err := run.Git("commit", "-m", fmt.Sprintf("%q", msg), "--author=\"user <user@example.com>\"").OnRepo(r.path).AndShutUp()
+	checkFatal(r.t, err)
+}
+
+func (r *Repo) branch(name string) {
+	err := run.Git("branch", name).OnRepo(r.path).AndShutUp()
+	checkFatal(r.t, err)
+}
+
+func (r *Repo) tag(name string) {
+	err := run.Git("tag", "-a", name, "-m", name).OnRepo(r.path).AndShutUp()
+	checkFatal(r.t, err)
+}
+
+func (r *Repo) checkout(name string) {
+	err := run.Git("checkout", name).OnRepo(r.path).AndShutUp()
+	checkFatal(r.t, err)
+}
+
+func (r *Repo) clone() *Repo {
+	dir := TempDir(r.t, "")
+
+	url := fmt.Sprintf("file://%s/.git", r.path)
+	err := run.Git("clone", url, dir).AndShutUp()
+	checkFatal(r.t, err)
+
+	clone := &Repo{
+		path: dir,
+		t:    r.t,
+	}
+
+	return clone
+}
+
+func (r *Repo) fetch() {
+	err := run.Git("fetch", "--all").OnRepo(r.path).AndShutUp()
+	checkFatal(r.t, err)
+}
+
+func checkFatal(t *testing.T, err error) {
+	if err != nil {
+		t.Fatalf("failed making test repo: %+v", err)
+	}
+}