function testDiffCalculation_ImplicitColumns() {
  var table = schema.table('tableA');
  var builder = new lf.query.SelectBuilder(lf.Global.get(), []);
  builder.from(table);
  var query = builder.getQuery();
  checkDiffCalculation(query, 'ImplicitColumns');
}
Tests the case where the observed query implicitly projects all columns.