return uint128{hi, lo}
}

func MkAddr(u Uint128, z unique.Handle[AddrDetail]) Addr {
	return Addr{u, z}
}

func IPv4(a, b, c, d uint8) Addr { return AddrFrom4([4]byte{a, b, c, d}) }

var TestAppendToMarshal = testAppendToMarshal

func (a Addr) IsZero() bool   { return a.isZero() }
func (p Prefix) IsZero() bool { return p.isZero() }

			}

			testAppendToMarshal(t, ipp)
		})
	}
}

type appendMarshaler interface {
	encoding.TextMarshaler
	AppendTo([]byte) []byte
}

// testAppendToMarshal tests that x's AppendTo and MarshalText methods yield the same results.
// x's MarshalText method must not return an error.
func testAppendToMarshal(t *testing.T, x appendMarshaler) {
	t.Helper()

			if wants == "" {
				wants = test.in
			}
			if s != wants {
				t.Errorf("ParseAddr(%q).String() got %q, want %q", test.in, s, wants)
			}

			// Check that AppendTo matches MarshalText.
			TestAppendToMarshal(t, got)

			// Check that MarshalText/UnmarshalText work similarly to
			// ParseAddr/String (see TestIPMarshalUnmarshal for
			// marshal-specific behavior that's not common with
			// ParseAddr/String).