public void testJoin() {
Parser<Relation> parser = RelationParser.join(TABLE, NUMBER);
assertParser(parser, "a", table("a"));
assertParser(parser, "a cross join table2 as b",
new CrossJoinRelation(table("a"), new AliasedRelation(table("table2"), "b")));
assertParser(parser, "a inner join b on 1",
new JoinRelation(table("a"), JoinType.INNER, table("b"), number(1)));
assertParser(parser, "a inner join b on 1 left join c on 2 cross join d",
new CrossJoinRelation(
new JoinRelation(