Extract billy (#173)

* Extract billy

Billy is a new library directly extracted from go-git. It abstract
several storages systems in a filesystem interface.

More in github.com/src-d/billy

* Fix grouping in imports block

* Update billy to v1

* Re-remove fs_implementation example

1 files changed, 6 insertions, 6 deletions

diff --git a/fixtures/fixtures.go b/fixtures/fixtures.go
index 00e7871..fdf852e 100644
--- a/fixtures/fixtures.go
+++ b/fixtures/fixtures.go
@@ -7,12 +7,12 @@ import (
 	"os"
 	"path/filepath"
 
-	"github.com/alcortesm/tgz"
-
 	"gopkg.in/check.v1"
 	"gopkg.in/src-d/go-git.v4/plumbing"
-	"gopkg.in/src-d/go-git.v4/utils/fs"
-	osfs "gopkg.in/src-d/go-git.v4/utils/fs/os"
+
+	"github.com/alcortesm/tgz"
+	"srcd.works/go-billy.v1"
+	osfs "srcd.works/go-billy.v1/os"
 )
 
 var RootFolder = ""
@@ -182,7 +182,7 @@ func (f *Fixture) Idx() *os.File {
 
 // DotGit creates a new temporary directory and unpacks the repository .git
 // directory into it. Multiple calls to DotGit returns different directories.
-func (f *Fixture) DotGit() fs.Filesystem {
+func (f *Fixture) DotGit() billy.Filesystem {
 	fn := filepath.Join(RootFolder, DataFolder, fmt.Sprintf("git-%s.tgz", f.DotGitHash))
 	path, err := tgz.Extract(fn)
 	if err != nil {
@@ -193,7 +193,7 @@ func (f *Fixture) DotGit() fs.Filesystem {
 	return osfs.New(path)
 }
 
-func (f *Fixture) Worktree() fs.Filesystem {
+func (f *Fixture) Worktree() billy.Filesystem {
 	fn := filepath.Join(RootFolder, DataFolder, fmt.Sprintf("git-%s.tgz", f.DotGitHash))
 	git, err := tgz.Extract(fn)
 	if err != nil {