add functions/vendor files

vendor/github.com/docker/distribution/digest/digester_resumable_test.go

@@ -0,0 +1,21 @@
+// +build !noresumabledigest
+
+package digest
+
+import (
+	"testing"
+
+	"github.com/stevvooe/resumable"
+	_ "github.com/stevvooe/resumable/sha256"
+)
+
+// TestResumableDetection just ensures that the resumable capability of a hash
+// is exposed through the digester type, which is just a hash plus a Digest
+// method.
+func TestResumableDetection(t *testing.T) {
+	d := Canonical.New()
+
+	if _, ok := d.Hash().(resumable.Hash); !ok {
+		t.Fatalf("expected digester to implement resumable.Hash: %#v, %v", d, d.Hash())
+	}
+}