tests := []struct {
		ip       []byte
		wantAddr Addr
		wantOK   bool
	}{
		{
			ip:       []byte{10, 0, 0, 1},
			wantAddr: mustIP("10.0.0.1"),
			wantOK:   true,
		},
		{
			ip:       []byte{0xfe, 0x80, 15: 0x01},
			wantAddr: mustIP("fe80::01"),
			wantOK:   true,
		},
		{
			ip:       []byte{0, 1, 2},
			wantAddr: Addr{},
			wantOK:   false,
		},
		{
			ip:       nil,

		{"subdir5/deleted.txt", "", true},
	}

	for _, tc := range testCases {
		gotPath, gotOK := OverlayPath(tc.path)
		if gotPath != tc.wantPath || gotOK != tc.wantOK {
			t.Errorf("OverlayPath(%q): got %v, %v; want %v, %v",
				tc.path, gotPath, gotOK, tc.wantPath, tc.wantOK)
		}
	}
}

func TestOpen(t *testing.T) {
	initOverlay(t, `
{
    "Replace": {

			if err != test.wErr {
				gotFitErr, gotOK := err.(*framework.FitError)
				wantFitErr, wantOK := test.wErr.(*framework.FitError)
				if gotOK != wantOK {
					t.Errorf("Expected err to be FitError: %v, but got %v (error: %v)", wantOK, gotOK, err)
				} else if gotOK {
					if diff := cmp.Diff(wantFitErr, gotFitErr); diff != "" {