1 files changed, 73 insertions, 0 deletions
diff --git a/activerecord/test/cases/arel/visitors/ibm_db_test.rb b/activerecord/test/cases/arel/visitors/ibm_db_test.rb
new file mode 100644
index 0000000000..2ddbec3266
--- /dev/null
+++ b/activerecord/test/cases/arel/visitors/ibm_db_test.rb
@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+require_relative "../helper"
+
+module Arel
+  module Visitors
+    class IbmDbTest < Arel::Spec
+      before do
+        @visitor = IBM_DB.new Table.engine.connection
+      end
+
+      def compile(node)
+        @visitor.accept(node, Collectors::SQLString.new).value
+      end
+
+      it "uses FETCH FIRST n ROWS to limit results" do
+        stmt = Nodes::SelectStatement.new
+        stmt.limit = Nodes::Limit.new(1)
+        sql = compile(stmt)
+        sql.must_be_like "SELECT FETCH FIRST 1 ROWS ONLY"
+      end
+
+      it "uses FETCH FIRST n ROWS 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 \"users\".\"id\" FROM \"users\" FETCH FIRST 1 ROWS ONLY)"
+      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 %{
+            DECODE("users"."name", 'Aaron Patterson', 0, 1) = 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 %{
+            DECODE("users"."first_name", "users"."last_name", 0, 1) = 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 %{
+            DECODE("users"."first_name", "users"."last_name", 0, 1) = 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