diff --git a/CHANGELOG.md b/CHANGELOG.md
index cfc83f78..a961eb97 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
 Changelog for Redmine DMSF
 ==========================
 
+3.0.1 *????-??-??*
+-------------------
+
+    Office documents displayed inline (preview)
+
 3.0.0 *2022-04-28*
 -------------------
 
diff --git a/Dockerfile b/Dockerfile
index ec5ac1ae..a1d2fb7e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -20,6 +20,6 @@
 
 FROM debian:latest
 RUN apt-get update
-RUN apt-get -qq install mariadb-server postgresql sqlite3 libsqlite3-dev ruby ruby-dev build-essential libmariadb-dev libpq-dev subversion git litmus
+RUN apt-get -qq install mariadb-server postgresql sqlite3 libsqlite3-dev ruby ruby-dev build-essential libmariadb-dev libpq-dev subversion git litmus libreoffice
 COPY . /app
 WORKDIR /app
diff --git a/README.md b/README.md
index 5c2625ee..d8752b5c 100644
--- a/README.md
+++ b/README.md
@@ -35,9 +35,11 @@ Features
   * Wiki macros for quick content linking
   * Full read/write webdav functionality
   * Optional document content full-text search
-  * Documents and folders symbolic links  
+  * Documents and folders' symbolic links  
   * Trash bin
   * Documents attachable to issues
+  * Office documents are displayed inline
+  * Editing of office documents
   * Compatible with Redmine 5.0.x
 
 Dependencies
@@ -112,6 +114,16 @@ sudo yum install xapian-core xapian-bindings-ruby libxapian-dev poppler-utils an
 libwps-tools gzip unrtf catdvi djview djview3 uuid uuid-dev xz libemail-outlook-message-perl
 ```
 
+### Inline displaying of office documents (optional)
+
+If LibreOffice binary `libreoffice` is present in the server, office documents (.odt, .ods,...) are displayed inline.
+
+`libreoffice` package is available in the most of Linux distributions, e.g. on Debain based systems:
+
+```
+sudo apt install libreoffice
+```            
+
 Usage
 -----
 
diff --git a/after_init.rb b/after_init.rb
index 6d73d194..0380ff06 100644
--- a/after_init.rb
+++ b/after_init.rb
@@ -21,12 +21,9 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
+require 'redmine'
 require 'zip'
-
-# All files in lib sub-folder are already loaded by Zeitwerk
-if RedmineApp::Application.config.autoloader != :zeitwerk
-  require File.dirname(__FILE__) + '/lib/redmine_dmsf'
-end
+require File.dirname(__FILE__) + '/lib/redmine_dmsf'
 
 def dmsf_init
   # Administration menu extension
diff --git a/app/controllers/dmsf_files_controller.rb b/app/controllers/dmsf_files_controller.rb
index 95c87b0c..b2ea82fd 100644
--- a/app/controllers/dmsf_files_controller.rb
+++ b/app/controllers/dmsf_files_controller.rb
@@ -69,10 +69,15 @@ class DmsfFilesController < ApplicationController
       member = Member.find_by(user_id: User.current.id, project_id: @file.project.id)
       # IE has got a tendency to cache files
       expires_in 0.year, 'must-revalidate' => true
-      send_file @revision.disk_file,
-        filename: filename_for_content_disposition(@revision.formatted_name(member)),
-        type: @revision.detect_content_type,
-        disposition: params[:disposition].present? ? params[:disposition] : @revision.dmsf_file.disposition
+      pdf_preview = @file.pdf_preview
+      filename = filename_for_content_disposition(@revision.formatted_name(member))
+      if pdf_preview.present?
+        basename = File.basename(filename, '.*')
+        send_file pdf_preview, filename: "#{basename}.pdf", type: 'application/pdf', disposition: 'inline'
+      else
+        send_file @revision.disk_file, filename: filename, type: @revision.detect_content_type,
+          disposition: params[:disposition].present? ? params[:disposition] : @revision.dmsf_file.disposition
+      end
     rescue RedmineDmsf::Errors::DmsfAccessError => e
       Rails.logger.error e.message
       render_403
diff --git a/app/models/dmsf_file.rb b/app/models/dmsf_file.rb
index 537e8466..7c1e63c9 100644
--- a/app/models/dmsf_file.rb
+++ b/app/models/dmsf_file.rb
@@ -78,6 +78,9 @@ class DmsfFile < ActiveRecord::Base
     project_key: 'project_id',
     date_column: "#{table_name}.updated_at"
 
+  cattr_accessor :previews_storage_path
+  @@previews_storage_path = File.join(Rails.root, 'tmp', 'dmsf_previews')
+
   before_create :default_values
 
   def default_values
@@ -465,23 +468,34 @@ class DmsfFile < ActiveRecord::Base
   end
 
   def text?
-    last_revision && Redmine::MimeType.is_type?('text', last_revision.disk_filename)
+    Redmine::MimeType.is_type?('text', last_revision&.disk_filename)
   end
 
   def image?
-    last_revision && Redmine::MimeType.is_type?('image', last_revision.disk_filename)
+    Redmine::MimeType.is_type?('image', last_revision&.disk_filename)
   end
 
   def pdf?
-    last_revision && (Redmine::MimeType.of(last_revision.disk_filename) == 'application/pdf')
+    Redmine::MimeType.of(last_revision&.disk_filename) == 'application/pdf'
   end
 
   def video?
-    last_revision && Redmine::MimeType.is_type?('video', last_revision.disk_filename)
+    Redmine::MimeType.is_type?('video', last_revision&.disk_filename)
   end
 
   def html?
-    last_revision && (Redmine::MimeType.of(last_revision.disk_filename) == 'text/html')
+    Redmine::MimeType.of(last_revision&.disk_filename) == 'text/html'
+  end
+
+  def office_doc?
+    case File.extname(last_revision&.disk_filename)
+    when  '.odt', '.ods', '.odp', '.odg', # LibreOffice
+          '.doc', '.docx', '.docm', '.xls', '.xlsx', '.xlsm', '.ppt', '.pptx', '.pptm',  # MS Office
+          '.rtf' # Universal
+          true
+    else
+      false
+    end
   end
 
   def disposition
@@ -492,7 +506,30 @@ class DmsfFile < ActiveRecord::Base
     image? && Redmine::Thumbnail.convert_available?
   end
 
-  def preview(limit)
+  def previewable?
+    office_doc? && RedmineDmsf::Preview.office_available?
+  end
+
+  # Deletes all previews
+  def self.clear_previews
+    Dir.glob(File.join(DmsfFile.previews_storage_path, '*.pdf')).each do |file|
+      File.delete file
+    end
+  end
+
+  def pdf_preview
+    return '' unless previewable?
+    target = File.join(DmsfFile.previews_storage_path, "#{id}_#{last_revision.digest}.pdf")
+
+    begin
+      RedmineDmsf::Preview.generate last_revision.disk_file.to_s, target
+    rescue => e
+      Rails.logger.error "An error occured while generating preview for #{last_revision.disk_file} to #{target}\nException was: #{e.message}"
+      nil
+    end
+  end
+
+  def text_preview(limit)
     result = +'No preview available'
     if text?
       begin
diff --git a/app/views/settings/_dmsf_settings.html.erb b/app/views/settings/_dmsf_settings.html.erb
index 50fdc3d8..0ea98586 100644
--- a/app/views/settings/_dmsf_settings.html.erb
+++ b/app/views/settings/_dmsf_settings.html.erb
@@ -106,10 +106,18 @@
   <% rescue %>
     <p class="warning"><%= l(:error_tmpfile_can_not_be_created) %></p>
   <% ensure %>
-    <% FileUtils.rm_f(testfilename) %>
+    <% FileUtils.rm_f testfilename %>
   <% end %>
 <% end %>
 
+<p>
+  <%= content_tag :label, l(:label_dmsf_office_bin) %>
+  <%= text_field_tag 'settings[office_bin]', @settings['office_bin'], size: 10 %>
+  <em class="info">
+    <%= l(:note_dmsf_office_bin) %> <%= l(:label_default) %>: 'libreoffice'
+  </em>
+</p>
+
 <p>
   <%= content_tag :label, l(:label_physical_file_delete) %>
   <%= check_box_tag 'settings[dmsf_really_delete_files]', true, @settings['dmsf_really_delete_files'] %>
diff --git a/config/locales/cs.yml b/config/locales/cs.yml
index f22d0a8b..be7f74d1 100644
--- a/config/locales/cs.yml
+++ b/config/locales/cs.yml
@@ -445,6 +445,9 @@ cs:
 
   label_dmsf_max_notification_receivers_info: Maximální počet zobrazených příjemců notifikace
   note_dmsf_max_notification_receivers_info: Omezí maximální počet zobrazených příjemců e-mailové notifikace
+  label_dmsf_office_bin: Binárka Libreofficu
+  note_dmsf_office_bin: Binárka ke konverzi kancelářských dokumentů do formátu PDF k poskytnutí jejich náhledu. Jestliže 
+    náhledy nechcete, vložte se například 'xxx'.
 
   easy_pages:
     modules:
diff --git a/config/locales/de.yml b/config/locales/de.yml
index 59f7e71a..be89b442 100644
--- a/config/locales/de.yml
+++ b/config/locales/de.yml
@@ -441,6 +441,9 @@ de:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 70da0fee..5920c927 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -445,6 +445,9 @@ en:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want 
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/es.yml b/config/locales/es.yml
index e47ad039..7a3f4382 100644
--- a/config/locales/es.yml
+++ b/config/locales/es.yml
@@ -445,6 +445,9 @@ es:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index 384c6945..a5ddb67b 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -445,6 +445,9 @@ fr:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/hu.yml b/config/locales/hu.yml
index 0e719d74..7f6947f6 100644
--- a/config/locales/hu.yml
+++ b/config/locales/hu.yml
@@ -444,6 +444,9 @@ hu:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/it.yml b/config/locales/it.yml
index aa1ecf5b..0b38b547 100644
--- a/config/locales/it.yml
+++ b/config/locales/it.yml
@@ -445,6 +445,9 @@ it: # Italian strings thx 2 Matteo Arceci!
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/ja.yml b/config/locales/ja.yml
index fdffef55..4bc00366 100644
--- a/config/locales/ja.yml
+++ b/config/locales/ja.yml
@@ -446,6 +446,9 @@ ja:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/ko.yml b/config/locales/ko.yml
index c1f6b718..52a6c84f 100644
--- a/config/locales/ko.yml
+++ b/config/locales/ko.yml
@@ -445,6 +445,9 @@ ko:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/nl.yml b/config/locales/nl.yml
index 6b00cbe1..50b91710 100644
--- a/config/locales/nl.yml
+++ b/config/locales/nl.yml
@@ -445,6 +445,9 @@ nl:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/pl.yml b/config/locales/pl.yml
index d5a7096d..e88ee576 100644
--- a/config/locales/pl.yml
+++ b/config/locales/pl.yml
@@ -445,6 +445,9 @@ pl:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/pt-BR.yml b/config/locales/pt-BR.yml
index 2a2b0012..9cd6088a 100644
--- a/config/locales/pt-BR.yml
+++ b/config/locales/pt-BR.yml
@@ -445,6 +445,9 @@ pt-BR:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/sl.yml b/config/locales/sl.yml
index 79b79be8..97ba539a 100644
--- a/config/locales/sl.yml
+++ b/config/locales/sl.yml
@@ -445,6 +445,9 @@ sl:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/zh-TW.yml b/config/locales/zh-TW.yml
index 2563e483..5f242f2a 100644
--- a/config/locales/zh-TW.yml
+++ b/config/locales/zh-TW.yml
@@ -444,6 +444,9 @@ zh-TW:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/config/locales/zh.yml b/config/locales/zh.yml
index e8b7189c..3f6363cf 100644
--- a/config/locales/zh.yml
+++ b/config/locales/zh.yml
@@ -445,6 +445,9 @@ zh:
 
   label_dmsf_max_notification_receivers_info: Maximum notification receivers info
   note_dmsf_max_notification_receivers_info: Limits maximum number of displayed email notification receivers.
+  label_dmsf_office_bin: Libreoffice binary
+  note_dmsf_office_bin: A binary to convert office documents to PDF format and provide their preview. If you want
+    to prevent previews of office documents, put here 'xxx' for example.
 
   easy_pages:
     modules:
diff --git a/init.rb b/init.rb
index 4171bb00..e2356d7d 100644
--- a/init.rb
+++ b/init.rb
@@ -33,7 +33,7 @@ Redmine::Plugin.register :redmine_dmsf do
   end
   author 'Vít Jonáš / Daniel Munn / Karel Pičman'
   description 'Document Management System Features'
-  version '3.0.0'
+  version '3.0.1 devel'
   
   requires_redmine version_or_higher: '4.2.0'
 
@@ -62,7 +62,8 @@ Redmine::Plugin.register :redmine_dmsf do
               'dmsf_webdav_ignore_1b_file_for_authentication' => '1',
               'dmsf_projects_as_subfolders' =>  nil,
               'only_approval_zero_minor_version' => '0',
-              'dmsf_max_notification_receivers_info' => 10
+              'dmsf_max_notification_receivers_info' => 10,
+              'office_bin' => 'libreoffice'
             }
 end
 
diff --git a/lib/redmine_dmsf/macros.rb b/lib/redmine_dmsf/macros.rb
index 1a1fa607..fb5d5cb1 100644
--- a/lib/redmine_dmsf/macros.rb
+++ b/lib/redmine_dmsf/macros.rb
@@ -144,7 +144,7 @@ module RedmineDmsf
         raise ArgumentError if args.length < 2 # Requires file id and lines number
         file = DmsfFile.visible.find args[0]
         if User.current&.allowed_to?(:view_dmsf_files, file.project)
-          file.preview(args[1]).gsub("\n", '<br/>').html_safe
+          file.text_preview(args[1]).gsub("\n", '<br/>').html_safe
         else
           raise l(:notice_not_authorized)
         end
diff --git a/lib/redmine_dmsf/preview.rb b/lib/redmine_dmsf/preview.rb
new file mode 100644
index 00000000..5969921f
--- /dev/null
+++ b/lib/redmine_dmsf/preview.rb
@@ -0,0 +1,65 @@
+# encoding: utf-8
+# frozen_string_literal: true
+#
+# Redmine plugin for Document Management System "Features"
+#
+# Copyright © 2011    Vít Jonáš <vit.jonas@gmail.com>
+# Copyright © 2011-22 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.
+
+module RedmineDmsf
+  module Preview
+    extend Redmine::Utils::Shell
+
+    OFFICE_BIN = (Setting.plugin_redmine_dmsf['office_bin'] || 'libreoffice').freeze
+
+    def self.office_available?
+      if defined?(@office_available)
+        return @office_available
+      end
+      begin
+        `#{shell_quote OFFICE_BIN} --version`
+        @office_available = $?.success?
+      rescue
+        @office_available = false
+      end
+      unless @office_available
+        logger.warn "LibreOffice's command line binary (#{OFFICE_BIN}) not available"
+      end
+      @office_available
+    end
+
+    def self.generate(source, target)
+      if File.exist?(target)
+        target
+      else
+        dir = File.dirname(target)
+        cmd = "#{shell_quote(OFFICE_BIN)} --convert-to pdf --headless --outdir #{shell_quote(dir)} #{shell_quote(source)}"
+        if system(cmd)
+          source_filename = File.basename(source, '.*')
+          target_filename = File.basename(target)
+          FileUtils.mv File.join(dir, "#{source_filename}.pdf"), File.join(dir, target_filename)
+          target
+        else
+          logger.error "Creating preview failed (#{$?}):\nCommand: #{cmd}"
+          ''
+        end
+      end
+    end
+
+  end
+
+end
diff --git a/test/fixtures/dmsf_file_revisions.yml b/test/fixtures/dmsf_file_revisions.yml
index 3d6afb09..a2acec65 100644
--- a/test/fixtures/dmsf_file_revisions.yml
+++ b/test/fixtures/dmsf_file_revisions.yml
@@ -255,4 +255,26 @@ dmsf_file_revisions_012:
   dmsf_workflow_assigned_by_user_id:  NULL
   dmsf_workflow_started_by_user_id:   NULL
   digest:                             '81dc9bdb52d04dc20036dbd8313ed055'
-  created_at:                         2022-02-03 13:39:27 +02:00
\ No newline at end of file
+  created_at:                         2022-02-03 13:39:27 +02:00
+
+dmsf_file_revisions_013:
+  id:                                 13
+  dmsf_file_id:                       13
+  source_dmsf_file_revision_id:       NULL
+  name:                               'test.odt'
+  disk_filename:                      'test.odt'
+  size:                               4
+  mime_type:                          'application/vnd.oasis.opendocument.text'
+  title:                              'Office document'
+  description:                        'LibreOffice text'
+  workflow:                           0
+  minor_version:                      0
+  major_version:                      1
+  comment:                            NULL
+  deleted:                            0
+  deleted_by_user_id:                 NULL
+  user_id:                            1
+  dmsf_workflow_assigned_by_user_id:  NULL
+  dmsf_workflow_started_by_user_id:   NULL
+  digest:                             '89a6d0ea9aafc21a978152f3e4977812d5d7d623505749471f256a90fc7c5f72'
+  created_at:                         2017-04-01 08:54:00 +02:00
\ No newline at end of file
diff --git a/test/fixtures/dmsf_files.yml b/test/fixtures/dmsf_files.yml
index 6b3bc9e5..f5e71b55 100644
--- a/test/fixtures/dmsf_files.yml
+++ b/test/fixtures/dmsf_files.yml
@@ -107,4 +107,12 @@ dmsf_files_012:
   name:               'test.txt'
   notification:       false
   deleted:            0
+  deleted_by_user_id: NULL
+
+dmsf_files_013:
+  id:                 13
+  project_id:         1
+  dmsf_folder_id:     NULL
+  name:               'test.odt'
+  deleted:            0
   deleted_by_user_id: NULL
\ No newline at end of file
diff --git a/test/functional/dmsf_files_controller_test.rb b/test/functional/dmsf_files_controller_test.rb
index 83b2b9e8..772e6934 100644
--- a/test/functional/dmsf_files_controller_test.rb
+++ b/test/functional/dmsf_files_controller_test.rb
@@ -30,6 +30,11 @@ class DmsfFilesControllerTest < RedmineDmsf::Test::TestCase
     @request.session[:user_id] = @jsmith.id
   end
 
+  def teardown
+    super
+    DmsfFile.clear_previews
+  end
+
   def test_show_file_ok
     # Permissions OK
     get :show, params: { id: @file1.id }
@@ -72,6 +77,13 @@ class DmsfFilesControllerTest < RedmineDmsf::Test::TestCase
     assert_response :forbidden
   end
 
+  def test_view_preview
+    get :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
     @role_manager.remove_permission! :file_manipulation
diff --git a/test/test_case.rb b/test/test_case.rb
index baeb9639..f2642b2b 100644
--- a/test/test_case.rb
+++ b/test/test_case.rb
@@ -67,6 +67,7 @@ module RedmineDmsf
         @file9 = DmsfFile.find 9
         @file10 = DmsfFile.find 10
         @file12 = DmsfFile.find 12
+        @file13 = DmsfFile.find 13
         @folder1 = DmsfFolder.find 1
         @folder2 = DmsfFolder.find 2
         @folder3 = DmsfFolder.find 3
diff --git a/test/unit/dmsf_file_test.rb b/test/unit/dmsf_file_test.rb
index 3719e61e..a2fdaa7b 100644
--- a/test/unit/dmsf_file_test.rb
+++ b/test/unit/dmsf_file_test.rb
@@ -280,4 +280,17 @@ class DmsfFileTest < RedmineDmsf::Test::UnitTest
     assert @file1.watched_by?(@jsmith)
   end
 
+  def test_office_doc
+    assert @file13.office_doc?
+  end
+
+  def test_previewable
+    assert @file13.previewable?
+  end
+
+  def test_pdf_preview
+    assert_not_empty @file13.pdf_preview
+    assert_empty @file1.pdf_preview
+  end
+
 end
\ No newline at end of file
diff --git a/test/unit/lib/redmine_dmsf/dmsf_macros_test.rb b/test/unit/lib/redmine_dmsf/dmsf_macros_test.rb
index 77af069f..e0d4c94e 100644
--- a/test/unit/lib/redmine_dmsf/dmsf_macros_test.rb
+++ b/test/unit/lib/redmine_dmsf/dmsf_macros_test.rb
@@ -202,19 +202,19 @@ class DmsfMacrosTest < RedmineDmsf::Test::HelperTest
   # {{dmsft(document_id)}}
   def test_macro_dmsft
     text = textilizable("{{dmsft(#{@file1.id}, 1)}}")
-    assert_equal "<p>#{@file1.preview(1)}</p>", text
+    assert_equal "<p>#{@file1.text_preview(1)}</p>", text
   end
 
   def test_macro_dmsft_no_permissions
     @manager_role.remove_permission! :view_dmsf_files
     text = textilizable("{{dmsft(#{@file1.id}, 1)}}")
-    assert_not_equal "<p>#{@file1.preview(1)}</p>", text
+    assert_not_equal "<p>#{@file1.text_preview(1)}</p>", text
   end
 
   def test_macro_dmsft_dmsf_off
     @project1.disable_module! :dmsf
     text = textilizable("{{dmsft(#{@file1.id}, 1)}}")
-    assert_not_equal "<p>#{@file1.preview(1)}</p>", text
+    assert_not_equal "<p>#{@file1.text_preview(1)}</p>", text
   end
 
   # {{dmsf_image(file_id)}}
diff --git a/test/unit_test.rb b/test/unit_test.rb
index af094f77..f506c4e3 100644
--- a/test/unit_test.rb
+++ b/test/unit_test.rb
@@ -53,6 +53,7 @@ module RedmineDmsf
         @file5 = DmsfFile.find 5
         @file7 = DmsfFile.find 7
         @file8 = DmsfFile.find 8
+        @file13 = DmsfFile.find 13
         @folder1 = DmsfFolder.find 1
         @folder2 = DmsfFolder.find 2
         @folder6 = DmsfFolder.find 6