Permit accessing basePath root in BasePathFs (with test)

basepath.go

@@ -27,8 +27,7 @@ func NewBasePathFs(source Fs, path string) Fs {
 // on a file outside the base path it returns the given file name and an error,
 // else the given file with the base path prepended
 func (b *BasePathFs) RealPath(name string) (path string, err error) {
-	bpath := filepath.Clean(b.path) + string(os.PathSeparator)
-
+	bpath := filepath.Clean(b.path)
 	path = filepath.Clean(filepath.Join(bpath, name))
 	if !strings.HasPrefix(path, bpath) {
 		return name, os.ErrNotExist

basepath_test.go

@@ -1,6 +1,7 @@
 package afero
 
 import (
+	"os"
 	"testing"
 )
 
@@ -17,3 +18,20 @@ func TestBasePath(t *testing.T) {
 		t.Errorf("succeeded in creating %s ...", fh.Name())
 	}
 }
+
+func TestBasePathRoot(t *testing.T) {
+	baseFs := &MemMapFs{}
+	baseFs.MkdirAll("/base/path/foo/baz", 0777)
+	baseFs.MkdirAll("/base/path/boo/", 0777)
+	bp := NewBasePathFs(baseFs, "/base/path")
+
+	rd, err := ReadDir(bp, string(os.PathSeparator))
+
+	if len(rd) != 2 {
+		t.Errorf("base path doesn't respect root")
+	}
+
+	if err != nil {
+		t.Error(err)
+	}
+}