.strictEqual(0, serializer.getOrAllocateDiagnosticId(
        'a', new tr.v.d.GenericSet(['b'])));
    assert.strictEqual(1, serializer.getOrAllocateDiagnosticId(
        'a', new tr.v.d.GenericSet(['c'])));
  });

  test('serialize', function() {
    const hist = new tr.v.Histogram(
        'aaa', tr.b.Unit.byName.count_biggerIsBetter);
    hist.description = 'lorem ipsum';
    hist.diagnostics.set('bbb', new tr.v.d.RelatedNameMap({
      ccc: 'a:c',
      ddd: 'a:d',
    }));
    hist.diagnostics.set('hhh