function testExec_GeomeanDistinctNullableColumn() {
  var tableA = schemaWithNullable.table('TableA');
  var inputRelation = lf.proc.Relation.fromRows(
      nullableGenerator.sampleTableARows, [tableA.getName()]);
  return checkCalculationForRelation(
      inputRelation, lf.fn.geomean(lf.fn.distinct(tableA['id'])),
      nullableGenerator.tableAGroundTruth.geomeanDistinctId, checkFloatEquals);
}
Tests for geomean distinct on TableA which has a mix of null and
non-null values for the column.
@return {!IThenable}