Postgresql doesn't allow to change a string type column to a binary type. Skip...

Postgresql doesn't allow to change a string type column to a binary type. Skip this test for postgresql for now. [#4616 state:resolved]
Signed-off-by: NJosé Valim <jose.valim@gmail.com>

activerecord/test/cases/migration_test.rb

@@ -860,13 +860,15 @@ def test_change_column_default
       assert_equal "Tester", Person.new.first_name
     end
 
-    def test_change_column_type_default_should_change
-      old_columns = Person.connection.columns(Person.table_name, "#{name} Columns")
-      assert !old_columns.find { |c| c.name == 'data' }
-
-      assert_nothing_raised do
-        Person.connection.add_column "people", "data", :string, :default => ''
-        Person.connection.change_column "people", "data", :binary
+    unless current_adapter?(:PostgreSQLAdapter)
+      def test_change_column_type_default_should_change
+        old_columns = Person.connection.columns(Person.table_name, "#{name} Columns")
+        assert !old_columns.find { |c| c.name == 'data' }
+
+        assert_nothing_raised do
+          Person.connection.add_column "people", "data", :string, :default => ''
+          Person.connection.change_column "people", "data", :binary
+        end
       end
     end