Added a basic test for the informix visitor

lib/arel/visitors.rb

@@ -11,6 +11,7 @@
 require 'arel/visitors/order_clauses'
 require 'arel/visitors/dot'
 require 'arel/visitors/ibm_db'
+require 'arel/visitors/informix'
 
 module Arel
   module Visitors
@@ -24,6 +25,7 @@ module Visitors
       'sqlite'          => Arel::Visitors::SQLite,
       'sqlite3'         => Arel::Visitors::SQLite,
       'ibm_db'          => Arel::Visitors::IBM_DB,
+      'informix'        => Arel::Visitors::Informix,
     }
 
     ENGINE_VISITORS = Hash.new do |hash, engine|

test/visitors/test_informix.rb

@@ -0,0 +1,34 @@
+require 'helper'
+
+module Arel
+  module Visitors
+    describe 'the informix visitor' do
+      before do
+        @visitor = Informix.new Table.engine
+      end
+
+      it 'uses LIMIT n to limit results' do
+        stmt = Nodes::SelectStatement.new
+        stmt.limit = Nodes::Limit.new(1)
+        sql = @visitor.accept(stmt)
+        sql.must_be_like "SELECT LIMIT 1"
+      end
+
+      it 'uses LIMIT n in updates with a limit' do
+        stmt = Nodes::UpdateStatement.new
+        stmt.limit = Nodes::Limit.new(1)
+        stmt.key = 'id'
+        sql = @visitor.accept(stmt)
+        sql.must_be_like "UPDATE NULL WHERE 'id' IN (SELECT LIMIT 1 'id')"
+      end
+
+      it 'uses SKIP n to jump results' do
+        stmt = Nodes::SelectStatement.new
+        stmt.offset = Nodes::Offset.new(10)
+        sql = @visitor.accept(stmt)
+        sql.must_be_like "SELECT SKIP 10"
+      end
+
+    end
+  end
+end