Assert AST shape for lowercase ARRAY JOIN

parser/altinity_array_join_test.go

@@ -17,3 +17,59 @@ func TestLowercaseArrayJoinExpressionList(t *testing.T) {
 		require.Equal(t, Format(stmts[0]), Format(parseOneStmt(t, Format(stmts[0]))))
 	}
 }
+
+func TestLowercaseArrayJoinAST(t *testing.T) {
+	type join struct {
+		modifiers []string
+		items     int
+	}
+	cases := []struct {
+		sql   string
+		joins []join
+	}{
+		{
+			sql:   "SELECT * FROM t array join spec_containers",
+			joins: []join{{modifiers: []string{"array", "JOIN"}, items: 1}},
+		},
+		{
+			sql:   "SELECT * FROM t array join a AS x, b AS y",
+			joins: []join{{modifiers: []string{"array", "JOIN"}, items: 2}},
+		},
+		{
+			sql: "SELECT * FROM t left array join a AS x join u ON t.id = u.id",
+			joins: []join{
+				{modifiers: []string{"left", "array", "JOIN"}, items: 1},
+				{modifiers: []string{"JOIN"}},
+			},
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.sql, func(t *testing.T) {
+			stmts, err := NewParser(tc.sql).ParseStmts()
+			require.NoError(t, err)
+			require.Len(t, stmts, 1)
+
+			query, ok := stmts[0].(*SelectQuery)
+			require.True(t, ok)
+			root, ok := query.From.Expr.(*JoinExpr)
+			require.True(t, ok)
+			require.IsType(t, &JoinTableExpr{}, root.Left)
+
+			next := root.Right
+			for _, want := range tc.joins {
+				j, ok := next.(*JoinExpr)
+				require.True(t, ok, "expected JoinExpr, got %T", next)
+				require.Equal(t, want.modifiers, j.Modifiers)
+				if want.items > 0 {
+					list, ok := j.Left.(*ColumnExprList)
+					require.True(t, ok, "expected ColumnExprList, got %T", j.Left)
+					require.Len(t, list.Items, want.items)
+				} else {
+					require.IsType(t, &JoinTableExpr{}, j.Left)
+				}
+				next = j.Right
+			}
+			require.Nil(t, next)
+		})
+	}
+}