diff --git a/.gitmodules b/.gitmodules
index 1e71b55..2e44f28 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -31,3 +31,6 @@
 [submodule "modules/cache"]
 	path = modules/cache
 	url = git@github.com:Oreolek/cache.git
+[submodule "modules/unittest"]
+	path = modules/unittest
+	url = git@github.com:kohana/unittest.git
diff --git a/application/classes/Controller/Subscription.php b/application/classes/Controller/Course.php
similarity index 74%
rename from application/classes/Controller/Subscription.php
rename to application/classes/Controller/Course.php
index fbac2a1..949f387 100644
--- a/application/classes/Controller/Subscription.php
+++ b/application/classes/Controller/Course.php
@@ -1,9 +1,9 @@
 <?php defined('SYSPATH') or die('No direct script access.');
 
 /**
- * Subscription controller.
+ * Course controller.
  **/
-class Controller_Subscription extends Controller_Layout {
+class Controller_Course extends Controller_Layout {
   protected $secure_actions = array(
     'index','create', 'edit', 'delete', 'view'
   );
@@ -16,9 +16,9 @@ class Controller_Subscription extends Controller_Layout {
   
   public function action_index()
   {
-    $this->template = new View_Subscription_Index;
-    $this->template->title = __('Subscription index');
-    $this->template->items = ORM::factory('Subscription')
+    $this->template = new View_Course_Index;
+    $this->template->title = __('Course index');
+    $this->template->items = ORM::factory('Course')
       ->filter_by_page($this->request->param('page'))
       ->find_all();
   }
@@ -26,17 +26,17 @@ class Controller_Subscription extends Controller_Layout {
   public function action_create()
   {
     $this->template = new View_Edit;
-    $this->template->model = ORM::factory('Subscription');
-    $this->template->title = __('New subscription');
+    $this->template->model = ORM::factory('Course');
+    $this->template->title = __('New course');
     $this->_edit($this->template->model);
   }
 
   public function action_edit()
   {
     $this->template = new View_Edit;
-    $this->template->title = __('Edit subscription');
+    $this->template->title = __('Edit course');
     $id = $this->request->param('id');
-    $model = ORM::factory('Subscription', $id);
+    $model = ORM::factory('Course', $id);
     if (!$model->loaded())
     {
       $this->redirect('error/404');
@@ -48,12 +48,12 @@ class Controller_Subscription extends Controller_Layout {
   {
     $this->template = new View_Delete;
     $id = $this->request->param('id');
-    $model = ORM::factory('Subscription', $id);
+    $model = ORM::factory('Course', $id);
     if (!$model->loaded())
     {
       $this->redirect('error/404');
     }
-    $this->template->title = __('Delete subscription');
+    $this->template->title = __('Delete course');
     $this->template->content_title = $model->title;
     $this->template->content = $model->description;
 
@@ -67,13 +67,13 @@ class Controller_Subscription extends Controller_Layout {
   {
     $this->template = new View_Letter_Index;
     $id = $this->request->param('id');
-    $model = ORM::factory('Subscription', $id)->with('letters');
+    $model = ORM::factory('Course', $id)->with('letters');
     if (!$model->loaded())
     {
       $this->redirect('error/404');
     }
-    $this->template->title = __('Subscription').' '.$model->title;
-    $this->template->subscription_id = $id;
+    $this->template->title = __('Course').' '.$model->title;
+    $this->template->course_id = $id;
     $this->template->items = $model->letters
       ->filter_by_page($this->request->param('page'))
       ->order_by('order')
@@ -82,14 +82,14 @@ class Controller_Subscription extends Controller_Layout {
 
   public function action_subscribe()
   {
-    $this->template = new View_Subscription_Subscribe;
+    $this->template = new View_Course_Subscribe;
     $id = $this->request->param('id');
-    $subscription = ORM::factory('Subscription', $id);
-    if (!$subscription->loaded())
+    $course = ORM::factory('Course', $id);
+    if (!$course->loaded())
     {
       $this->redirect('error/404');
     }
-    $this->template->title = __('Subscribe to ').$subscription->title;
+    $this->template->title = __('Subscribe to ').$course->title;
     $controls = array(
       'name' => 'input',
       'email' => 'input'
@@ -108,9 +108,9 @@ class Controller_Subscription extends Controller_Layout {
         if ($validation->check())
         {
           $model->save();
-          $model->add('subscription', $subscription);
+          $model->add('course', $course);
           $task = ORM::factory('Task');
-          $letter = $subscription->next_letter();
+          $letter = $course->next_letter();
           $task->letter_id = $letter->id;
           $task->client_id = $model->id;
           // now we break the abstraction to speed things up
diff --git a/application/classes/Controller/Letter.php b/application/classes/Controller/Letter.php
index 2acfb3a..d05f854 100644
--- a/application/classes/Controller/Letter.php
+++ b/application/classes/Controller/Letter.php
@@ -16,12 +16,12 @@ class Controller_Letter extends Controller_Layout {
   {
     $this->template = new View_Edit;
     $id = $this->request->param('id');
-    if (!Model_Subscription::exists($id))
+    if (!Model_Course::exists($id))
     {
       $this->redirect('error/500');
     }
     $this->template->model = ORM::factory('Letter');
-    $this->template->model->subscription_id = $id;
+    $this->template->model->course_id = $id;
     $this->template->title = __('New letter');
     $this->_edit($this->template->model);
   }
diff --git a/application/classes/Model/Subscription.php b/application/classes/Model/Course.php
similarity index 70%
rename from application/classes/Model/Subscription.php
rename to application/classes/Model/Course.php
index 84b8755..6133d7b 100644
--- a/application/classes/Model/Subscription.php
+++ b/application/classes/Model/Course.php
@@ -1,16 +1,16 @@
 <?php defined('SYSPATH') OR die('No direct access allowed.');
 /**
- * Subscription model.
- * Subscription is an ordered collection of letters.
+ * Course model.
+ * Course is an ordered collection of letters.
  * It has a period in days. Every <period> days a client receives a letter from the collection.
  * @package Models
  * @author Oreolek
  **/
-class Model_Subscription extends ORM {
+class Model_Course extends ORM {
   protected $_has_many = array(
     'client' => array(
       'model' => 'Client',
-      'through' => 'clients_subscriptions'
+      'through' => 'clients_courses'
     ),
     'letters' => array(
       'model' => 'Letter'
@@ -62,7 +62,7 @@ class Model_Subscription extends ORM {
 
   public static function count_letters($id)
   {
-    return DB::select(array(DB::expr('COUNT(*)'), 'cnt'))->from('letters')->where('subscription_id', '=', $id)->execute()->get('cnt');
+    return DB::select(array(DB::expr('COUNT(*)'), 'cnt'))->from('letters')->where('course_id', '=', $id)->execute()->get('cnt');
   }
 
   /**
@@ -70,55 +70,55 @@ class Model_Subscription extends ORM {
    **/
   public function count_clients()
   {
-    return DB::select(array(DB::expr('COUNT(client_id)'), 'cnt'))->from('clients_subscriptions')->where('subscription_id', '=', $this->id)->execute()->get('cnt');
+    return DB::select(array(DB::expr('COUNT(client_id)'), 'cnt'))->from('clients_courses')->where('course_id', '=', $this->id)->execute()->get('cnt');
   }
 
   public static function exists($id)
   {
-    $count = DB::select(array(DB::expr('COUNT(*)'), 'cnt'))->from('subscriptions')->where('id', '=', $id)->execute()->get('cnt');
+    $count = DB::select(array(DB::expr('COUNT(*)'), 'cnt'))->from('courses')->where('id', '=', $id)->execute()->get('cnt');
     return ($count == 1);
   }
 
   public static function get_ids()
   {
-    return DB::select('id')->from('subscriptions')->execute()->get('id');
+    return DB::select('id')->from('courses')->execute()->get('id');
   }
 
-  public static function get_period($subscription_id)
+  public static function get_period($course_id)
   {
     return DB::select('period')
-      ->from('subscriptions')
-      ->where('subscription_id', '=', $subscription_id)
+      ->from('courses')
+      ->where('course_id', '=', $course_id)
       ->execute()
       ->get('period');
   }
 
-  public static function get_letter_ids($subscription_id)
+  public static function get_letter_ids($course_id)
   {
     return DB::select('id')
       ->from('letters')
-      ->where('subscription_id', '=', $subscription_id)
+      ->where('course_id', '=', $course_id)
       ->order_by('order')
       ->execute()
       ->get('id');
   }
-  public static function get_client_ids($subscription_id)
+  public static function get_client_ids($course_id)
   {
     return DB::select('client_id')
-      ->from('clients_subscriptions')
-      ->where('subscription_id', '=', $subscription_id)
+      ->from('clients_courses')
+      ->where('course_id', '=', $course_id)
       ->execute()
       ->get('client_id');
   }
 
   /**
-   * Get next letter in subscription
+   * Get next letter in course
    * @param int $offset search offset (typically number of already sent letters)
    **/
   public function next_letter($offset = 0)
   {
     return ORM::factory('Letter')
-      ->where('subscription_id', '=', $this->id)
+      ->where('course_id', '=', $this->id)
       ->order_by('order', 'ASC')
       ->limit(1)
       ->offset($offset)
@@ -139,10 +139,10 @@ class Model_Subscription extends ORM {
     }
     $query->execute();
     DB::delete('letters')
-      ->where('subscription_id', '=', $this->id)
+      ->where('course_id', '=', $this->id)
       ->execute();
-    DB::delete('clients_subscriptions')
-      ->where('subscription_id', '=', $this->id)
+    DB::delete('clients_courses')
+      ->where('course_id', '=', $this->id)
       ->execute();
     return parent::delete();
   }
diff --git a/application/classes/Model/Letter.php b/application/classes/Model/Letter.php
index 7db2162..6ea971d 100644
--- a/application/classes/Model/Letter.php
+++ b/application/classes/Model/Letter.php
@@ -7,7 +7,7 @@
  **/
 class Model_Letter extends ORM {
   protected $belongs_to = array(
-    'subscription'
+    'course'
   );
   
   /**
@@ -44,7 +44,7 @@ class Model_Letter extends ORM {
   {
     if(empty($this->order))
     {
-      $this->order = Model_Subscription::count_letters($this->subscription_id) + 1;
+      $this->order = Model_Course::count_letters($this->course_id) + 1;
     }
   }
 
@@ -62,7 +62,7 @@ class Model_Letter extends ORM {
    * @param $address string or array of strings - email addresses
    * @param $text message body
    * @param $subject message subject
-   * @param $token user subscription token
+   * @param $token user course token
    **/
   public static function _send($address, $text, $subject, $token = '')
   {
diff --git a/application/classes/Task/Prepare.php b/application/classes/Task/Prepare.php
index 925791d..238daa7 100644
--- a/application/classes/Task/Prepare.php
+++ b/application/classes/Task/Prepare.php
@@ -10,16 +10,16 @@ class Task_Prepare extends Minion_Task
 {
   protected $_options = array();
   /**
-   * @param int $subscription subscription ID
+   * @param int $course course ID
    **/
-  protected function prepare_subscription($subscription)
+  protected function prepare_course($course)
   {
-    $count = Model_Subscription::count_letters($subscription);
+    $count = Model_Course::count_letters($course);
     if ($count == 0)
       return;
-    $period = Model_Subscription::get_period($subscription);
-    $clients = Model_Subscription::get_client_ids($subscription, $period);
-    $letters = Model_Subscription::get_letter_ids($subscription);
+    $period = Model_Course::get_period($course);
+    $clients = Model_Course::get_client_ids($course, $period);
+    $letters = Model_Course::get_letter_ids($course);
     if (!is_array($clients))
     {
       $this->prepare_letters($clients, $letters, $period);
@@ -47,7 +47,7 @@ class Task_Prepare extends Minion_Task
 
   /**
    * Prepare letters to be sent out.
-   * If a client received less letters from subscription than there is in subscription,
+   * If a client received less letters from course than there is in course,
    * a task is formed.
    *
    * @return null
@@ -58,17 +58,16 @@ class Task_Prepare extends Minion_Task
     $db->begin();
     try
     {
-      $subscriptions = Model_Subscription::get_ids();
-      echo __('Total subscription count').': '.count($subscriptions)."\n";
-      if (!is_array($subscriptions))
+      $courses = Model_Course::get_ids();
+      if (!is_array($courses))
       {
-        $this->prepare_subscription($subscriptions);
+        $this->prepare_course($courses);
       }
       else
       {
-        foreach ($subscriptions as $subscription)
+        foreach ($courses as $course)
         {
-          $this->prepare_subscription($subscription);
+          $this->prepare_course($course);
         } 
       }
       $db->commit();
diff --git a/application/classes/View/Subscription/Index.php b/application/classes/View/Course/Index.php
similarity index 93%
rename from application/classes/View/Subscription/Index.php
rename to application/classes/View/Course/Index.php
index fc65ece..1e2129f 100644
--- a/application/classes/View/Subscription/Index.php
+++ b/application/classes/View/Course/Index.php
@@ -1,11 +1,11 @@
 <?php defined('SYSPATH') OR die('No direct script access.');
 
 /**
- * Subscription index view controller.
+ * Course index view controller.
  * @package Views
  * @author Oreolek
  **/
-class View_Subscription_Index extends View_Index {
+class View_Course_Index extends View_Index {
   protected $is_admin = TRUE; // admin only view
   public $show_date = FALSE;
   public function get_header()
diff --git a/application/classes/View/Subscription/Subscribe.php b/application/classes/View/Course/Subscribe.php
similarity index 52%
rename from application/classes/View/Subscription/Subscribe.php
rename to application/classes/View/Course/Subscribe.php
index 89903cc..4f966d1 100644
--- a/application/classes/View/Subscription/Subscribe.php
+++ b/application/classes/View/Course/Subscribe.php
@@ -1,8 +1,8 @@
 <?php defined('SYSPATH') or die('No direct script access.');
 
 /**
- * Subscription form view controller
+ * Course subscription form view controller
  **/
-class View_Subscription_Subscribe extends View_Edit {
+class View_Course_Subscribe extends View_Edit {
   public $_layout = 'empty';
 }
diff --git a/application/classes/View/Layout.php b/application/classes/View/Layout.php
index 9cf4912..2a09403 100644
--- a/application/classes/View/Layout.php
+++ b/application/classes/View/Layout.php
@@ -77,7 +77,7 @@ class View_Layout {
     else
     {
       $navigation = array_merge($navigation, array(
-        __('Subscriptions') => 'subscription/index',
+        __('Courses') => 'course/index',
         'Клиенты' => 'client/index',
         'Поиск клиентов' => 'client/search',
       ));
diff --git a/application/config/database.php.example b/application/config/database.php.example
index 9c27f1b..afdb162 100644
--- a/application/config/database.php.example
+++ b/application/config/database.php.example
@@ -28,18 +28,15 @@ return array
     'caching'      => TRUE,
     'profiling'    => FALSE,
   ),
-  'sphinx' => array(
-    'type'       => 'MySQLi',
+  'test' => array(
+    'type' => 'MySQL',
     'connection' => array(
-      'hostname'   => 'localhost:9306',
-      'database'   => 'oreolek', // index name from sphinx config
+      'hostname'   => 'localhost',
+      'database'   => 'oreolek',
       'username'   => '',
       'password'   => '',
       'persistent' => FALSE,
-    ),
-    'charset'      => 'utf8',
-    'caching'      => TRUE,
-    'profiling'    => FALSE,
-  ),
+    )
+  )
 );
 
diff --git a/application/i18n/ru.php b/application/i18n/ru.php
index 3a8bfa3..912ba42 100644
--- a/application/i18n/ru.php
+++ b/application/i18n/ru.php
@@ -16,6 +16,7 @@ return array(
   'Mailing date' => 'Дата отправки',
   'Status' => 'Статус',
   'Subscriptions' => 'Рассылки',
+  'Courses' => 'Курсы',
   'No objects found to show' => 'Не найдено объектов для отображения.',
   'Add' => 'Добавить',
   'Edit' => 'Редактировать',
@@ -27,6 +28,11 @@ return array(
   'Edit subscription' => 'Редактировать рассылку',
   'Subscribe to ' => 'Подписка на ',
   'Subscription' => 'Рассылка',
+  'Course' => 'Курс',
+  'New course' => 'Новый курс',
+  'Course index' => 'Список курсов',
+  'Delete course' => 'Удалить курс',
+  'Edit course' => 'Редактировать курс',
   'Name' => 'Имя',
   'You were subscribed. A welcome email has been sent to you. Please check your inbox.' => 'Вы были подписаны. Вам было выслано вступительное письмо; пожалуйста, проверьте входящие сообщения.',
   'New letter' => 'Новое письмо',
@@ -36,6 +42,7 @@ return array(
   'Message subject' => 'Тема письма',
   'The password was successfully changed.' => 'Пароль был успешно изменён.',
   'Total subscription count' => 'Всего подписок',
+  'Total course count' => 'Всего курсов',
   'Sending letter with subject "%subject" to address %address' => 'Отсылаю письмо с темой %subject на адрес %address',
   'Clients' => 'Клиенты',
   'Description' => 'Описание',
diff --git a/application/templates/subscription/index.mustache b/application/templates/course/index.mustache
similarity index 100%
rename from application/templates/subscription/index.mustache
rename to application/templates/course/index.mustache
diff --git a/application/templates/subscription/subscribe.mustache b/application/templates/course/subscribe.mustache
similarity index 100%
rename from application/templates/subscription/subscribe.mustache
rename to application/templates/course/subscribe.mustache
diff --git a/application/tests/CoursesTest.php b/application/tests/CoursesTest.php
new file mode 100644
index 0000000..d642826
--- /dev/null
+++ b/application/tests/CoursesTest.php
@@ -0,0 +1,50 @@
+<?php
+
+/**
+  * Test for course workflow.
+  * @category Tests
+  * @author Oreolek
+  * @license AGPL
+  **/
+class CoursesTest extends Unittest_Database_TestCase
+{
+  protected $_database_connection = 'test';
+
+  protected function getdataset()
+  {
+    return $this->createXMLDataSet(Kohana::find_file('tests', 'test_data/courses', 'xml'));
+  }
+
+  public function getSetUpOperation() {
+    // whether you want cascading truncates
+    // set false if unsure
+    $cascadeTruncates = false;
+
+    return new PHPUnit_Extensions_Database_Operation_Composite(array(
+      new PHPUnit_Extensions_Database_Operation_MySQL55Truncate($cascadeTruncates),
+      PHPUnit_Extensions_Database_Operation_Factory::INSERT()
+    ));
+  }
+
+  /**
+   * @group Mail
+   **/
+  function testPrepareCourse()
+  {
+    Minion_Task::factory(array('task' => 'prepare'))->execute();
+    $status = DB::select('status')->from('tasks')->where('letter_id', '=', '1')->and_where('client_id','=','1')->execute()->get('status');
+    $this->assertEquals(Model_Task::STATUS_PENDING, $status);
+  }
+
+  function testSendCourse()
+  {
+    $status = DB::select('status')->from('tasks')->where('letter_id', '=', '1')->and_where('client_id','=','1')->execute()->get('status');
+    if (is_null($status))
+    {
+      DB::insert('tasks', array('letter_id', 'client_id', 'date', 'status'))->values(array('1','1',date('Y-m-d'), Model_Task::STATUS_PENDING))->execute();
+    }
+    Minion_Task::factory(array('task' => 'send'))->execute();
+    $status = DB::select('status')->from('tasks')->where('letter_id', '=', '1')->and_where('client_id','=','1')->execute()->get('status');
+    $this->assertEquals(Model_Task::STATUS_SENT, $status);
+  }
+}
diff --git a/application/tests/bootstrap.php b/application/tests/bootstrap.php
new file mode 100644
index 0000000..52b23ed
--- /dev/null
+++ b/application/tests/bootstrap.php
@@ -0,0 +1,11 @@
+<?php
+require_once '../../modules/unittest/bootstrap.php';
+class PHPUnit_Extensions_Database_Operation_MySQL55Truncate extends PHPUnit_Extensions_Database_Operation_Truncate
+{
+  public function execute(PHPUnit_Extensions_Database_DB_IDatabaseConnection $connection, PHPUnit_Extensions_Database_DataSet_IDataSet $dataSet) {
+    $connection->getConnection()->query("SET @PHAKE_PREV_foreign_key_checks = @@foreign_key_checks");
+    $connection->getConnection()->query("SET foreign_key_checks = 0");
+    parent::execute($connection, $dataSet);
+    $connection->getConnection()->query("SET foreign_key_checks = @PHAKE_PREV_foreign_key_checks");
+  }
+}
diff --git a/application/tests/phpunit.xml b/application/tests/phpunit.xml
new file mode 100644
index 0000000..b5e743b
--- /dev/null
+++ b/application/tests/phpunit.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit colors="true" bootstrap="./bootstrap.php">
+  <testsuites>
+    <testsuite name="Application Tests">
+      <file>../../modules/unittest/tests.php</file>
+    </testsuite>
+  </testsuites>
+  <groups>
+    <exclude>
+      <group>kohana</group>
+    </exclude>
+  </groups>
+</phpunit>
diff --git a/application/tests/test_data/courses.xml b/application/tests/test_data/courses.xml
new file mode 100644
index 0000000..03bd0e8
--- /dev/null
+++ b/application/tests/test_data/courses.xml
@@ -0,0 +1,67 @@
+<?xml version="1.0" ?>
+<dataset>
+  <table name="courses">
+    <column>id</column>
+    <column>title</column>
+    <column>description</column>
+    <column>period</column>
+    <column>price</column>
+    <row>
+      <value>1</value>
+      <value>Test course</value>
+      <value>Application testing purposes</value>
+      <value>1</value>
+      <value>0</value>
+    </row>
+  </table>
+  <table name="clients">
+    <column>id</column>
+    <column>email</column>
+    <column>name</column>
+    <column>token</column>
+    <row>
+      <value>1</value>
+      <value>test@example.com</value>
+      <value>Test User</value>
+      <value></value><!-- empty token -->
+    </row>
+  </table>
+  <table name="clients_courses">
+    <column>id</column>
+    <column>client_id</column>
+    <column>course_id</column>
+    <row>
+      <value>1</value>
+      <value>1</value>
+      <value>1</value>
+    </row>
+  </table>
+  <table name="letters">
+    <column>id</column>
+    <column>text</column>
+    <column>course_id</column>
+    <column>order</column>
+    <column>subject</column>
+    <row>
+      <value>1</value>
+      <value>This is a test message. Please ignore it.</value>
+      <value>1</value>
+      <value>0</value>
+      <value>Test message #1</value>
+    </row>
+    <row>
+      <value>2</value>
+      <value>This is a test message number two. Please ignore it.</value>
+      <value>1</value>
+      <value>1</value>
+      <value>Test message #2</value>
+    </row>
+  </table>
+  <table name="tasks">
+    <column>id</column>
+    <column>letter_id</column>
+    <column>client_id</column>
+    <column>date</column>
+    <column>status</column>
+  </table>
+</dataset>
diff --git a/model.mwb b/model.mwb
index cdf23c1..a4b901a 100644
Binary files a/model.mwb and b/model.mwb differ
diff --git a/modules/unittest b/modules/unittest
new file mode 160000
index 0000000..8db01f0
--- /dev/null
+++ b/modules/unittest
@@ -0,0 +1 @@
+Subproject commit 8db01f00d6d94781e0e8750cc7d586221e771cc7