diff --git a/app/controllers/dmsf_files_controller.rb b/app/controllers/dmsf_files_controller.rb
index 790e5e82..afcd9e7d 100644
--- a/app/controllers/dmsf_files_controller.rb
+++ b/app/controllers/dmsf_files_controller.rb
@@ -121,7 +121,7 @@ class DmsfFilesController < ApplicationController
       revision = DmsfFileRevision.new
       revision.title = params[:dmsf_file_revision][:title].scrub.strip
       revision.name = params[:dmsf_file_revision][:name].scrub.strip
-      revision.description = params[:dmsf_file_revision][:description].scrub.strip
+      revision.description = params[:dmsf_file_revision][:description]&.scrub&.strip
       revision.comment = params[:dmsf_file_revision][:comment].scrub.strip
       revision.dmsf_file = @file
       last_revision = @file.last_revision
diff --git a/app/models/dmsf_file_revision.rb b/app/models/dmsf_file_revision.rb
index 97437907..bc0cf6ec 100644
--- a/app/models/dmsf_file_revision.rb
+++ b/app/models/dmsf_file_revision.rb
@@ -446,7 +446,7 @@ class DmsfFileRevision < ApplicationRecord
         value = value.except('blank')
         _, v = value.first
         # We need a symbols here
-        result[key] = if v.key?('file') && v['file'].blank?
+        result[key] = if v&.key?('file') && v['file'].blank?
                         nil
                       else
                         v&.symbolize_keys
diff --git a/test/functional/dmsf_files_controller_test.rb b/test/functional/dmsf_files_controller_test.rb
new file mode 100644
index 00000000..67477417
--- /dev/null
+++ b/test/functional/dmsf_files_controller_test.rb
@@ -0,0 +1,151 @@
+# frozen_string_literal: true
+
+# Redmine plugin for Document Management System "Features"
+#
+# Copyright © 2011-23 Karel Pičman <karel.picman@kontron.com>
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+require File.expand_path('../../test_helper', __FILE__)
+
+# DmsfFiles controller
+class DmsfFilesControllerTest < RedmineDmsf::Test::TestCase
+  fixtures :dmsf_folders, :dmsf_files, :dmsf_file_revisions, :dmsf_locks
+
+  def teardown
+    super
+    DmsfFile.clear_previews
+  end
+
+  def test_show_file_ok
+    # Permissions OK
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    get "/dmsf/files/#{@file1.id}", params: { id: @file1.id }
+    assert_response :success
+  end
+
+  def test_show_formatting_html
+    Setting.text_formatting = 'HTML'
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    get "/dmsf/files/#{@file1.id}", params: { id: @file1.id }
+    assert_response :success
+    assert_include 'dmsf-description', response.body, 'dmsf-description class not found'
+    assert_include 'wiki-edit', response.body, 'wiki-edit class not found'
+  end
+
+  def test_show_formatting_textile
+    Setting.text_formatting = 'Textile'
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    get "/dmsf/files/#{@file1.id}", params: { id: @file1.id }
+    assert_response :success
+    assert_include 'dmsf-description', response.body, 'dmsf-description class not found'
+    assert_include 'wiki-edit', response.body, 'wiki-edit class not found'
+  end
+
+  def test_show_file_forbidden
+    # Missing permissions
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    @role_manager.remove_permission! :view_dmsf_files
+    get "/dmsf/files/#{@file1.id}", params: { id: @file1.id }
+    assert_response :forbidden
+  end
+
+  def test_view_file_ok
+    # Permissions OK
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    get "/dmsf/files/#{@file1.id}/view", params: { id: @file1.id }
+    assert_response :success
+  end
+
+  def test_view_file_forbidden
+    # Missing permissions
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    @role_manager.remove_permission! :view_dmsf_files
+    get "/dmsf/files/#{@file1.id}/view", params: { id: @file1.id }
+    assert_response :forbidden
+  end
+
+  def test_view_preview
+    return unless RedmineDmsf::Preview.office_available?
+
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    get "/dmsf/files/#{@file13.id}/view", params: { id: @file13.id }
+    assert_response :success
+    assert_equal 'application/pdf', @response.media_type
+    assert @response.body.starts_with?('%PDF')
+  end
+
+  def delete_forbidden
+    # Missing permissions
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    @role_manager.remove_permission! :file_manipulation
+    delete "/dmsf/files/#{@file1.id}", params: { id: @file1.id, folder_id: @file1.dmsf_folder.id, commit: false }
+    assert_response :forbidden
+  end
+
+  def delete_locked
+    # Permissions OK but the file is locked
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    delete "/dmsf/files/#{@file2.id}", params: { id: @file2.id, folder_id: @file2.dmsf_folder.id, commit: false }
+    assert_response :redirect
+    assert_include l(:error_file_is_locked), flash[:error]
+  end
+
+  def delete_ok
+    # Permissions OK and not locked
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    delete "/dmsf/files/#{@file1.id}", params: { id: @file1.id, folder_id: @file1.dmsf_folder.id, commit: false }
+    assert_redirected_to dmsf_folder_path(id: @file1.project, folder_id: @file1.dmsf_folder.id)
+  end
+
+  def test_delete_in_subfolder
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    delete "/dmsf/files/#{@file4.id}", params: { id: @file4.id, folder_id: @file4.dmsf_folder.id, commit: false }
+    assert_redirected_to dmsf_folder_path(id: @file4.project, folder_id: @file4.dmsf_folder.id)
+  end
+
+  def test_obsolete_revision_ok
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    get "/dmsf/files/#{@file1.id}/revision/obsolete", params: { id: @file1.last_revision.id }
+    assert_redirected_to action: 'show', id: @file1
+  end
+
+  def test_obsolete_revision_missing_permissions
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    @role_manager.remove_permission! :file_manipulation
+    get "/dmsf/files/#{@file1.id}/revision/obsolete", params: { id: @file1.last_revision.id }
+    assert :forbiden
+  end
+
+  def test_create_revision
+    post '/login', params: { username: 'jsmith', password: 'jsmith' }
+    assert_difference 'DmsfFileRevision.count', +1 do
+      post "/dmsf/files/#{@file1.id}/revision/create",
+           params: {
+             id: @file1.id,
+             version_major: @file1.last_revision.major_version,
+             version_minor: @file1.last_revision.minor_version + 1,
+             dmsf_file_revision: {
+               title: @file1.last_revision.title,
+               name: @file1.last_revision.name,
+               description: @file1.last_revision.description,
+               comment: 'New revision'
+             }
+           }
+    end
+    assert_redirected_to dmsf_folder_path(id: @file1.project)
+    assert_not_nil @file1.last_revision.digest
+  end
+end
diff --git a/test/unit/lib/acccess_control_patch_test.rb b/test/unit/lib/acccess_control_patch_test.rb
index 823b33ad..ad645faf 100644
--- a/test/unit/lib/acccess_control_patch_test.rb
+++ b/test/unit/lib/acccess_control_patch_test.rb
@@ -23,9 +23,11 @@ require File.expand_path('../../../test_helper', __FILE__)
 # AccessControl patch tests
 class AccessControlPatchTest < RedmineDmsf::Test::UnitTest
   def test_available_project_modules
-    Setting.plugin_redmine_dmsf['remove_original_documents_module'] = nil
     assert Redmine::AccessControl.available_project_modules.include?(:documents)
-    Setting.plugin_redmine_dmsf['remove_original_documents_module'] = '1'
-    assert_not Redmine::AccessControl.available_project_modules.include?(:documents)
+    return if defined?(EasyExtensions) # It doesn't work with Easy due to alias_method_change
+
+    with_settings plugin_redmine_dmsf: { 'remove_original_documents_module' => '1' } do
+      assert_not Redmine::AccessControl.available_project_modules.include?(:documents)
+    end
   end
 end
diff --git a/test/unit/lib/search_patch_test.rb b/test/unit/lib/search_patch_test.rb
index 6f3aeaa5..5b62e2d6 100644
--- a/test/unit/lib/search_patch_test.rb
+++ b/test/unit/lib/search_patch_test.rb
@@ -23,9 +23,11 @@ require File.expand_path('../../../test_helper', __FILE__)
 # Search patch tests
 class SearchPatchTest < RedmineDmsf::Test::UnitTest
   def test_available_search_types
-    Setting.plugin_redmine_dmsf['remove_original_documents_module'] = nil
     assert Redmine::Search.available_search_types.include?('documents')
-    Setting.plugin_redmine_dmsf['remove_original_documents_module'] = '1'
-    assert_not Redmine::Search.available_search_types.include?('documents')
+    return if defined?(EasyExtensions) # It doesn't work with Easy due to alias_method_change
+
+    with_settings plugin_redmine_dmsf: { 'remove_original_documents_module' => '1' } do
+      assert_not Redmine::Search.available_search_types.include?('documents')
+    end
   end
 end