1 files changed, 98 insertions, 0 deletions
diff --git a/activerecord/test/cases/arel/visitors/informix_test.rb b/activerecord/test/cases/arel/visitors/informix_test.rb
new file mode 100644
index 0000000000..b6c2dd6ae7
--- /dev/null
+++ b/activerecord/test/cases/arel/visitors/informix_test.rb
@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require_relative "../helper"
+
+module Arel
+  module Visitors
+    class InformixTest < Arel::Spec
+      before do
+        @visitor = Informix.new Table.engine.connection
+      end
+
+      def compile(node)
+        @visitor.accept(node, Collectors::SQLString.new).value
+      end
+
+      it "uses FIRST n to limit results" do
+        stmt = Nodes::SelectStatement.new
+        stmt.limit = Nodes::Limit.new(1)
+        sql = compile(stmt)
+        sql.must_be_like "SELECT FIRST 1"
+      end
+
+      it "uses FIRST n in updates with a limit" do
+        table = Table.new(:users)
+        stmt = Nodes::UpdateStatement.new
+        stmt.relation = table
+        stmt.limit = Nodes::Limit.new(Nodes.build_quoted(1))
+        stmt.key = table[:id]
+        sql = compile(stmt)
+        sql.must_be_like "UPDATE \"users\" WHERE \"users\".\"id\" IN (SELECT FIRST 1 \"users\".\"id\" FROM \"users\")"
+      end
+
+      it "uses SKIP n to jump results" do
+        stmt = Nodes::SelectStatement.new
+        stmt.offset = Nodes::Offset.new(10)
+        sql = compile(stmt)
+        sql.must_be_like "SELECT SKIP 10"
+      end
+
+      it "uses SKIP before FIRST" do
+        stmt = Nodes::SelectStatement.new
+        stmt.limit = Nodes::Limit.new(1)
+        stmt.offset = Nodes::Offset.new(1)
+        sql = compile(stmt)
+        sql.must_be_like "SELECT SKIP 1 FIRST 1"
+      end
+
+      it "uses INNER JOIN to perform joins" do
+        core = Nodes::SelectCore.new
+        table = Table.new(:posts)
+        core.source = Nodes::JoinSource.new(table, [table.create_join(Table.new(:comments))])
+
+        stmt = Nodes::SelectStatement.new([core])
+        sql = compile(stmt)
+        sql.must_be_like 'SELECT FROM "posts" INNER JOIN "comments"'
+      end
+
+      describe "Nodes::IsNotDistinctFrom" do
+        it "should construct a valid generic SQL statement" do
+          test = Table.new(:users)[:name].is_not_distinct_from "Aaron Patterson"
+          compile(test).must_be_like %{
+            CASE WHEN "users"."name" = 'Aaron Patterson' OR ("users"."name" IS NULL AND 'Aaron Patterson' IS NULL) THEN 0 ELSE 1 END = 0
+          }
+        end
+
+        it "should handle column names on both sides" do
+          test = Table.new(:users)[:first_name].is_not_distinct_from Table.new(:users)[:last_name]
+          compile(test).must_be_like %{
+            CASE WHEN "users"."first_name" = "users"."last_name" OR ("users"."first_name" IS NULL AND "users"."last_name" IS NULL) THEN 0 ELSE 1 END = 0
+          }
+        end
+
+        it "should handle nil" do
+          @table = Table.new(:users)
+          val = Nodes.build_quoted(nil, @table[:active])
+          sql = compile Nodes::IsNotDistinctFrom.new(@table[:name], val)
+          sql.must_be_like %{ "users"."name" IS NULL }
+        end
+      end
+
+      describe "Nodes::IsDistinctFrom" do
+        it "should handle column names on both sides" do
+          test = Table.new(:users)[:first_name].is_distinct_from Table.new(:users)[:last_name]
+          compile(test).must_be_like %{
+            CASE WHEN "users"."first_name" = "users"."last_name" OR ("users"."first_name" IS NULL AND "users"."last_name" IS NULL) THEN 0 ELSE 1 END = 1
+          }
+        end
+
+        it "should handle nil" do
+          @table = Table.new(:users)
+          val = Nodes.build_quoted(nil, @table[:active])
+          sql = compile Nodes::IsDistinctFrom.new(@table[:name], val)
+          sql.must_be_like %{ "users"."name" IS NOT NULL }
+        end
+      end
+    end
+  end
+end