Refactor configuration of cache dir and repository

test/backend.go

@@ -3,7 +3,6 @@ package test_helper
 import (
 	"flag"
 	"io/ioutil"
-	"os"
 	"path/filepath"
 	"testing"
 
@@ -25,10 +24,6 @@ func SetupRepo(t testing.TB) *repository.Repository {
 	b, err := local.Create(filepath.Join(tempdir, "repo"))
 	OK(t, err)
 
-	// set cache dir below temp dir
-	err = os.Setenv("RESTIC_CACHE", filepath.Join(tempdir, "cache"))
-	OK(t, err)
-
 	repo := repository.New(b)
 	OK(t, repo.Init(*TestPassword))
 	return repo