raise a better exception for renaming long indexes

1 files changed, 14 insertions, 0 deletions

diff --git a/activerecord/test/cases/migration/index_test.rb b/activerecord/test/cases/migration/index_test.rb
index ac932378fd..b23b9a679f 100644
--- a/activerecord/test/cases/migration/index_test.rb
+++ b/activerecord/test/cases/migration/index_test.rb
@@ -36,6 +36,20 @@ module ActiveRecord
         assert connection.index_name_exists?(table_name, 'new_idx', true)
       end
 
+      def test_rename_index_too_long
+        too_long_index_name = good_index_name + 'x'
+        # keep the names short to make Oracle and similar behave
+        connection.add_index(table_name, [:foo], :name => 'old_idx')
+        e = assert_raises(ArgumentError) {
+          connection.rename_index(table_name, 'old_idx', too_long_index_name)
+        }
+        assert_match(/too long; the limit is #{connection.allowed_index_name_length} characters/, e.message)
+
+        # if the adapter doesn't support the indexes call, pick defaults that let the test pass
+        assert connection.index_name_exists?(table_name, 'old_idx', false)
+      end
+
+
       def test_double_add_index
         connection.add_index(table_name, [:foo], :name => 'some_idx')
         assert_raises(ArgumentError) {