function testDeferrable_ImplicitTx_Success() {
  var parentRow = sampleRows[0];

  return db.insert().into(parentTable).values([parentRow]).exec().then(
      function() {
        return lf.testing.util.selectAll(global, parentTable);
      }).then(
      function(results) {
        assertEquals(1, results.length);
        assertEquals(parentRow.payload()['id'], results[0].payload()['id']);
      });
}
Tests that a query that does not violate DEFERRABLE constraints completes
successfully when an implicit transaction is used.
@return {!IThenable}