public void testImmutableEntrySerialization() {
    Cell<String, Integer, Character> entry = immutableCell("foo", 1, 'a');
    SerializableTester.reserializeAndAssert(entry);
  }

  public void testImmutableEntryToString() {
    Cell<String, Integer, Character> entry = immutableCell("foo", 1, 'a');
    assertEquals("(foo,1)=a", entry.toString());

    Cell<@Nullable String, @Nullable Integer, @Nullable Character> nullEntry =