only run citext_test if the connection supports_extensions?.

This will keep the test suite passing with older PG installations.

activerecord/test/cases/adapters/postgresql/citext_test.rb

@@ -4,74 +4,76 @@
 require 'active_record/base'
 require 'active_record/connection_adapters/postgresql_adapter'
 
-class PostgresqlCitextTest < ActiveRecord::TestCase
-  class Citext < ActiveRecord::Base
-    self.table_name = 'citexts'
-  end
+if ActiveRecord::Base.connection.supports_extensions?
+  class PostgresqlCitextTest < ActiveRecord::TestCase
+    class Citext < ActiveRecord::Base
+      self.table_name = 'citexts'
+    end
 
-  def setup
-    @connection = ActiveRecord::Base.connection
+    def setup
+      @connection = ActiveRecord::Base.connection
 
-    unless @connection.extension_enabled?('citext')
-      @connection.enable_extension 'citext'
-      @connection.commit_db_transaction
-    end
+      unless @connection.extension_enabled?('citext')
+        @connection.enable_extension 'citext'
+        @connection.commit_db_transaction
+      end
 
-    @connection.reconnect!
+      @connection.reconnect!
 
-    @connection.create_table('citexts') do |t|
-      t.citext 'cival'
+      @connection.create_table('citexts') do |t|
+        t.citext 'cival'
+      end
+      @column = Citext.columns_hash['cival']
     end
-    @column = Citext.columns_hash['cival']
-  end
 
-  teardown do
-    @connection.execute 'DROP TABLE IF EXISTS citexts;'
-    @connection.execute 'DROP EXTENSION IF EXISTS citext CASCADE;'
-  end
+    teardown do
+      @connection.execute 'DROP TABLE IF EXISTS citexts;'
+      @connection.execute 'DROP EXTENSION IF EXISTS citext CASCADE;'
+    end
 
-  def test_citext_enabled
-    assert @connection.extension_enabled?('citext')
-  end
+    def test_citext_enabled
+      assert @connection.extension_enabled?('citext')
+    end
 
-  def test_column_type
-    assert_equal :citext, @column.type
-  end
+    def test_column_type
+      assert_equal :citext, @column.type
+    end
 
-  def test_column_sql_type
-    assert_equal 'citext', @column.sql_type
-  end
+    def test_column_sql_type
+      assert_equal 'citext', @column.sql_type
+    end
+
+    def test_change_table_supports_json
+      @connection.transaction do
+        @connection.change_table('citexts') do |t|
+          t.citext 'username'
+        end
+        Citext.reset_column_information
+        column = Citext.columns.find { |c| c.name == 'username' }
+        assert_equal :citext, column.type
 
-  def test_change_table_supports_json
-    @connection.transaction do
-      @connection.change_table('citexts') do |t|
-        t.citext 'username'
+        raise ActiveRecord::Rollback # reset the schema change
       end
+    ensure
       Citext.reset_column_information
-      column = Citext.columns.find { |c| c.name == 'username' }
-      assert_equal :citext, column.type
-
-      raise ActiveRecord::Rollback # reset the schema change
     end
-  ensure
-    Citext.reset_column_information
-  end
 
-  def test_write
-    x = Citext.new(cival: 'Some CI Text')
-    x.save!
-    citext = Citext.first
-    assert_equal "Some CI Text", citext.cival
+    def test_write
+      x = Citext.new(cival: 'Some CI Text')
+      x.save!
+      citext = Citext.first
+      assert_equal "Some CI Text", citext.cival
 
-    citext.cival = "Some NEW CI Text"
-    citext.save!
+      citext.cival = "Some NEW CI Text"
+      citext.save!
 
-    assert_equal "Some NEW CI Text", citext.reload.cival
-  end
+      assert_equal "Some NEW CI Text", citext.reload.cival
+    end
 
-  def test_select_case_insensitive
-    @connection.execute "insert into citexts (cival) values('Cased Text')"
-    x = Citext.where(cival: 'cased text').first
-    assert_equal 'Cased Text', x.cival
+    def test_select_case_insensitive
+      @connection.execute "insert into citexts (cival) values('Cased Text')"
+      x = Citext.where(cival: 'cased text').first
+      assert_equal 'Cased Text', x.cival
+    end
   end
 end