Limit revision's description text length

app/models/dmsf_file_revision.rb

@@ -55,6 +55,7 @@ class DmsfFileRevision < ActiveRecord::Base
   validates :title, :presence => true
   validates_format_of :name, :with => DmsfFolder::INVALID_CHARACTERS,
     :message => l(:error_contains_invalid_character)
+  validates :description, length: { maximum: 1.megabyte }
 
   def project
     self.dmsf_file.project if self.dmsf_file

test/unit/dmsf_file_revision_test.rb

@@ -210,4 +210,11 @@ class DmsfFileRevisionTest < RedmineDmsf::Test::UnitTest
     assert_equal -(' '.ord), @revision1.minor_version
   end
 
+  def description_max_length
+    @revision1.description = 2.megabytes * 'a'
+    assert !@revision1.save
+    @revision1.description = 1.megabyte * 'a'
+    assert @revision1.save
+  end
+
 end