diff --git a/cohort/tests/cohortlib_test.php b/cohort/tests/cohortlib_test.php
new file mode 100644
index 00000000000..82e9520d8d5
--- /dev/null
+++ b/cohort/tests/cohortlib_test.php
@@ -0,0 +1,181 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle 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 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Cohort library tests.
+ *
+ * @package    core_cohort
+ * @category   phpunit
+ * @copyright  2012 Petr Skoda {@link http://skodak.org}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+global $CFG;
+require_once("$CFG->dirroot/cohort/lib.php");
+
+
+/**
+ * Cohort library tests.
+ *
+ * @package    core_cohort
+ * @category   phpunit
+ * @copyright  2012 Petr Skoda {@link http://skodak.org}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cohort_testcase extends advanced_testcase {
+
+    public function test_cohort_add_cohort() {
+        global $DB;
+
+        $this->resetAfterTest();
+
+        $cohort = new stdClass();
+        $cohort->contextid = context_system::instance()->id;
+        $cohort->name = 'test cohort';
+        $cohort->idnumber = 'testid';
+        $cohort->description = 'test cohort desc';
+        $cohort->descriptionformat = FORMAT_HTML;
+
+        $id = cohort_add_cohort($cohort);
+        $this->assertNotEmpty($id);
+
+        $newcohort = $DB->get_record('cohort', array('id'=>$id));
+        $this->assertEquals($cohort->contextid, $newcohort->contextid);
+        $this->assertSame($cohort->name, $newcohort->name);
+        $this->assertSame($cohort->description, $newcohort->description);
+        $this->assertEquals($cohort->descriptionformat, $newcohort->descriptionformat);
+        $this->assertNotEmpty($newcohort->timecreated);
+        $this->assertSame($newcohort->component, '');
+        $this->assertSame($newcohort->timecreated, $newcohort->timemodified);
+
+        try {
+            $cohort = new stdClass();
+            $cohort->contextid = context_system::instance()->id;
+            $cohort->name = null;
+            $cohort->idnumber = 'testid';
+            $cohort->description = 'test cohort desc';
+            $cohort->descriptionformat = FORMAT_HTML;
+            cohort_add_cohort($cohort);
+
+            $this->fail('Exception expected when trying to add cohort without name');
+        } catch (Exception $e) {
+            $this->assertInstanceOf('coding_exception', $e);
+        }
+    }
+
+    public function test_cohort_update_cohort() {
+        global $DB;
+
+        $this->resetAfterTest();
+
+        $cohort = new stdClass();
+        $cohort->contextid = context_system::instance()->id;
+        $cohort->name = 'test cohort';
+        $cohort->idnumber = 'testid';
+        $cohort->description = 'test cohort desc';
+        $cohort->descriptionformat = FORMAT_HTML;
+        $id = cohort_add_cohort($cohort);
+        $this->assertNotEmpty($id);
+        $DB->set_field('cohort', 'timecreated', $cohort->timecreated - 10, array('id'=>$id));
+        $DB->set_field('cohort', 'timemodified', $cohort->timemodified - 10, array('id'=>$id));
+        $cohort = $DB->get_record('cohort', array('id'=>$id));
+
+        $cohort->name = 'test cohort 2';
+        cohort_update_cohort($cohort);
+
+        $newcohort = $DB->get_record('cohort', array('id'=>$id));
+
+        $this->assertSame($cohort->contextid, $newcohort->contextid);
+        $this->assertSame($cohort->name, $newcohort->name);
+        $this->assertSame($cohort->description, $newcohort->description);
+        $this->assertSame($cohort->descriptionformat, $newcohort->descriptionformat);
+        $this->assertSame($cohort->timecreated, $newcohort->timecreated);
+        $this->assertSame($cohort->component, $newcohort->component);
+        $this->assertGreaterThan($newcohort->timecreated, $newcohort->timemodified);
+        $this->assertLessThanOrEqual(time(), $newcohort->timemodified);
+    }
+
+    public function test_cohort_delete_cohort() {
+        global $DB;
+
+        $this->resetAfterTest();
+
+        $cohort = $this->getDataGenerator()->create_cohort();
+
+        cohort_delete_cohort($cohort);
+
+        $this->assertFalse($DB->record_exists('cohort', array('id'=>$cohort->id)));
+    }
+
+    public function test_cohort_delete_category() {
+        global $DB;
+
+        $this->resetAfterTest();
+
+        $category = $this->getDataGenerator()->create_category();
+
+        $cohort = $this->getDataGenerator()->create_cohort(array('contextid'=>context_coursecat::instance($category->id)->id));
+
+        cohort_delete_category($category);
+
+        $this->assertTrue($DB->record_exists('cohort', array('id'=>$cohort->id)));
+        $newcohort = $DB->get_record('cohort', array('id'=>$cohort->id));
+        $this->assertEquals(context_system::instance()->id, $newcohort->contextid);
+    }
+
+    public function test_cohort_add_member() {
+        global $DB;
+
+        $this->resetAfterTest();
+
+        $cohort = $this->getDataGenerator()->create_cohort();
+        $user = $this->getDataGenerator()->create_user();
+
+        $this->assertFalse($DB->record_exists('cohort_members', array('cohortid'=>$cohort->id, 'userid'=>$user->id)));
+        cohort_add_member($cohort->id, $user->id);
+        $this->assertTrue($DB->record_exists('cohort_members', array('cohortid'=>$cohort->id, 'userid'=>$user->id)));
+    }
+
+    public function test_cohort_remove_member() {
+        global $DB;
+
+        $this->resetAfterTest();
+
+        $cohort = $this->getDataGenerator()->create_cohort();
+        $user = $this->getDataGenerator()->create_user();
+
+        cohort_add_member($cohort->id, $user->id);
+        $this->assertTrue($DB->record_exists('cohort_members', array('cohortid'=>$cohort->id, 'userid'=>$user->id)));
+
+        cohort_remove_member($cohort->id, $user->id);
+        $this->assertFalse($DB->record_exists('cohort_members', array('cohortid'=>$cohort->id, 'userid'=>$user->id)));
+    }
+
+    public function test_cohort_is_member() {
+        global $DB;
+
+        $this->resetAfterTest();
+
+        $cohort = $this->getDataGenerator()->create_cohort();
+        $user = $this->getDataGenerator()->create_user();
+
+        $this->assertFalse(cohort_is_member($cohort->id, $user->id));
+        cohort_add_member($cohort->id, $user->id);
+        $this->assertTrue(cohort_is_member($cohort->id, $user->id));
+    }
+}
diff --git a/lib/phpunit/classes/data_generator.php b/lib/phpunit/classes/data_generator.php
index 8225f236761..515f062ee24 100644
--- a/lib/phpunit/classes/data_generator.php
+++ b/lib/phpunit/classes/data_generator.php
@@ -36,6 +36,7 @@
 class phpunit_data_generator {
     protected $usercounter = 0;
     protected $categorycount = 0;
+    protected $cohortcount = 0;
     protected $coursecount = 0;
     protected $scalecount = 0;
     protected $groupcount = 0;
@@ -218,7 +219,7 @@ EOD;
      * @param array $options
      * @return stdClass course category record
      */
-    function create_category($record=null, array $options=null) {
+    public function create_category($record=null, array $options=null) {
         global $DB, $CFG;
         require_once("$CFG->dirroot/course/lib.php");
 
@@ -270,6 +271,50 @@ EOD;
         return $DB->get_record('course_categories', array('id'=>$catid), '*', MUST_EXIST);
     }
 
+    /**
+     * Create test cohort.
+     * @param array|stdClass $record
+     * @param array $options
+     * @return stdClass cohort record
+     */
+    public function create_cohort($record=null, array $options=null) {
+        global $DB, $CFG;
+        require_once("$CFG->dirroot/cohort/lib.php");
+
+        $this->cohortcount++;
+        $i = $this->cohortcount;
+
+        $record = (array)$record;
+
+        if (!isset($record['contextid'])) {
+            $record['contextid'] = context_system::instance()->id;
+        }
+
+        if (!isset($record['name'])) {
+            $record['name'] = 'Cohort '.$i;
+        }
+
+        if (!isset($record['idnumber'])) {
+            $record['idnumber'] = '';
+        }
+
+        if (!isset($record['description'])) {
+            $record['description'] = "Test cohort $i\n$this->loremipsum";
+        }
+
+        if (!isset($record['descriptionformat'])) {
+            $record['descriptionformat'] = FORMAT_MOODLE;
+        }
+
+        if (!isset($record['component'])) {
+            $record['component'] = '';
+        }
+
+        $id = cohort_add_cohort((object)$record);
+
+        return $DB->get_record('cohort', array('id'=>$id), '*', MUST_EXIST);
+    }
+
     /**
      * Create a test course
      * @param array|stdClass $record
@@ -277,7 +322,7 @@ EOD;
      *      'createsections'=>bool precreate all sections
      * @return stdClass course record
      */
-    function create_course($record=null, array $options=null) {
+    public function create_course($record=null, array $options=null) {
         global $DB, $CFG;
         require_once("$CFG->dirroot/course/lib.php");
 
diff --git a/lib/phpunit/tests/generator_test.php b/lib/phpunit/tests/generator_test.php
index 316ee706561..9c6f4f6bbae 100644
--- a/lib/phpunit/tests/generator_test.php
+++ b/lib/phpunit/tests/generator_test.php
@@ -53,6 +53,18 @@ class core_phpunit_generator_testcase extends advanced_testcase {
         $this->assertRegExp('/^Test course category \d/', $category->description);
         $this->assertSame(FORMAT_MOODLE, $category->descriptionformat);
 
+        $count = $DB->count_records('cohort');
+        $cohort = $generator->create_cohort();
+        $this->assertEquals($count+1, $DB->count_records('cohort'));
+        $this->assertEquals(context_system::instance()->id, $cohort->contextid);
+        $this->assertRegExp('/^Cohort \d/', $cohort->name);
+        $this->assertSame('', $cohort->idnumber);
+        $this->assertRegExp('/^Test cohort \d/', $cohort->description);
+        $this->assertSame(FORMAT_MOODLE, $cohort->descriptionformat);
+        $this->assertSame('', $cohort->component);
+        $this->assertLessThanOrEqual(time(), $cohort->timecreated);
+        $this->assertSame($cohort->timecreated, $cohort->timemodified);
+
         $count = $DB->count_records('course');
         $course = $generator->create_course();
         $this->assertEquals($count+1, $DB->count_records('course'));
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 1e65824d203..cf5e58a2a9b 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -39,6 +39,9 @@
         <testsuite name="core_files">
             <directory suffix="_test.php">lib/filestorage/tests</directory>
         </testsuite>
+        <testsuite name="core_cohort">
+            <directory suffix="_test.php">cohort/tests</directory>
+        </testsuite>
         <testsuite name="core_grade">
             <directory suffix="_test.php">lib/grade/tests</directory>
             <directory suffix="_test.php">grade/tests</directory>