// Should get an exception when we try to serialize.
    RuntimeException ex = assertThrows(RuntimeException.class, () -> reserialize(memoizedSupplier));
    assertThat(ex).hasCauseThat().isInstanceOf(NotSerializableException.class);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testMemoizeSerializable() throws Exception {

          encoding.decode(cannotDecode);
          fail("Expected IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
          if (expectedMessage != null) {
            assertThat(expected).hasCauseThat().hasMessageThat().isEqualTo(expectedMessage);
          }
        }
      }
    },
    DECODE_CHECKED {
      @Override
      void assertFailsToDecode(