Added failing test case for changing schema in migration not clearing…

… the prepared statement cache

activerecord/test/cases/query_cache_test.rb

@@ -170,6 +170,18 @@ def test_cache_does_not_wrap_string_results_in_arrays
 class QueryCacheExpiryTest < ActiveRecord::TestCase
   fixtures :tasks, :posts, :categories, :categories_posts
 
+  def test_cache_gets_cleared_after_migration
+    # warm the cache
+    Post.find(1)
+
+    # change the column definition
+    Post.connection.change_column :posts, :title, :string, :limit => 80
+    assert_nothing_raised { Post.find(1) }
+
+    # restore the old definition
+    Post.connection.change_column :posts, :title, :string
+  end
+
   def test_find
     Task.connection.expects(:clear_query_cache).times(1)