diff --git a/admin/inc/class.admin_cmd_edit_preferences.inc.php b/admin/inc/class.admin_cmd_edit_preferences.inc.php
index 8dff565d11..2014d0e098 100644
--- a/admin/inc/class.admin_cmd_edit_preferences.inc.php
+++ b/admin/inc/class.admin_cmd_edit_preferences.inc.php
@@ -80,11 +80,11 @@ class admin_cmd_edit_preferences extends admin_cmd
 		{
 			if (!isset($value) || $value === '')
 			{
-				$prefs->delete($this->app, $name, in_array($this->pref, 'default', 'forced') ? $this->pref : 'user');
+				$prefs->delete($this->app, $name, in_array($this->pref, array('default', 'forced')) ? $this->pref : 'user');
 			}
 			else
 			{
-				$prefs->add($this->app, $name, $value, in_array($this->pref, 'default', 'forced') ? $this->pref : 'user');
+				$prefs->add($this->app, $name, $value, in_array($this->pref, array('default', 'forced')) ? $this->pref : 'user');
 			}
 		}
 		$prefs->save_repository(true, $this->pref);
diff --git a/admin/tests/PreferencesCommandTest.php b/admin/tests/PreferencesCommandTest.php
new file mode 100644
index 0000000000..a862e8eb82
--- /dev/null
+++ b/admin/tests/PreferencesCommandTest.php
@@ -0,0 +1,300 @@
+<?php
+
+/**
+ * Tests for edit preferences command
+ *
+ * @link http://www.egroupware.org
+ * @author Nathan Gray
+ * @copyright (c) 2018  Nathan Gray
+ * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
+ */
+
+// test base providing common stuff
+require_once __DIR__.'/CommandBase.php';
+
+use EGroupware\Api;
+
+class PreferencesCommandTest extends CommandBase
+{
+
+	// Use the same app for everything
+	const APP = 'common';
+
+	// If we add a preference, make sure we can delete it for clean up
+	protected $preference_name = 'test_preference';
+
+	public function setUp()
+	{
+		Api\Cache::unsetInstance(Api\Preferences::class, 'forced');
+		Api\Cache::unsetInstance(Api\Preferences::class, 'default');
+		Api\Cache::unsetInstance(Api\Preferences::class, $GLOBALS['egw_info']['user']['account_id']);
+	}
+	public function tearDown()
+	{
+		if($this->preference_name)
+		{
+			Api\Preferences::delete_preference(static::APP, $this->preference_name, 'user');
+			Api\Preferences::delete_preference(static::APP, $this->preference_name, 'default');
+			Api\Preferences::delete_preference(static::APP, $this->preference_name, 'forced');
+		}
+
+		Api\Cache::unsetInstance(Api\Preferences::class, 'forced');
+		Api\Cache::unsetInstance(Api\Preferences::class, 'default');
+		Api\Cache::unsetInstance(Api\Preferences::class, $GLOBALS['egw_info']['user']['account_id']);
+		parent::tearDown();
+	}
+
+	/**
+	 * Test that adding a preference works
+	 *
+	 * @dataProvider typeDataProvider
+	 */
+	public function testAddPreference($type)
+	{
+		// Set up
+		$log_count = $this->get_log_count();
+		$account = $type == 'group' ? $GLOBALS['egw']->accounts->name2id('Default') : $GLOBALS['egw_info']['user']['account_id'];
+		$pre_pref = new Api\Preferences($GLOBALS['egw_info']['user']['account_id']);
+		$pre = $pre_pref->read(static::APP);
+		$this->assertArrayNotHasKey($this->preference_name, $pre);
+
+		$set = array($this->preference_name => 'Yes');
+
+		// Execute
+		$command = new admin_cmd_edit_preferences($account, $type, static::APP, $set);
+		$command->comment = 'Needed for unit test ' . $this->getName() . " with type $type";
+		$command->run();
+
+		// Check
+		$post_pref = new Api\Preferences($GLOBALS['egw_info']['user']['account_id']);
+		$post = $post_pref->read_repository(false);
+		// At user level
+		$this->assertArrayHasKey($this->preference_name, $post[static::APP]);
+		$this->assertEquals($set[$this->preference_name], $post[static::APP][$this->preference_name]);
+		// At type level
+		$this->assertArrayHasKey($this->preference_name, $post_pref->$type[static::APP]);
+		$this->assertEquals($set[$this->preference_name], $post_pref->$type[static::APP][$this->preference_name]);
+
+		$this->assertGreaterThan($log_count, $this->get_log_count(), "Command ($command) did not log");
+	}
+
+	/**
+	 * Try to change an existing preference
+	 *
+	 * We check changing the various combinations with a default set.
+	 * All should give a change.
+	 *
+	 * @dataProvider typeDataProvider
+	 */
+	public function testChangeWithDefault($type)
+	{
+		// Set up
+		$log_count = $this->get_log_count();
+		$account = $GLOBALS['egw_info']['user']['account_id'];
+
+		$set = array($this->preference_name => 'Changed');
+		$old = array($this->preference_name => $type . ' original value');
+
+		$prefs = new Api\Preferences('default');
+		$prefs->read_repository(false);
+		$prefs->add(static::APP, $this->preference_name, 'default original value','default');
+		$prefs->save_repository('default');
+
+		$prefs = new Api\Preferences(in_array($type, array('default', 'forced')) ? $type : $account);
+		$prefs->read_repository(false);
+		$prefs->add(static::APP, $this->preference_name, $old[$this->preference_name], $type);
+		$prefs->save_repository($type);
+
+		// Execute
+		$command = new admin_cmd_edit_preferences($account, $type, static::APP, $set, $old);
+		$command->comment = 'Needed for unit test ' . $this->getName();
+		$command->run();
+
+		// Check
+		$post_pref = new Api\Preferences($account);
+		$post = $post_pref->read_repository(false);
+
+		// At user level
+		$this->assertArrayHasKey($this->preference_name, $post[static::APP]);
+		$this->assertEquals($set[$this->preference_name], $post[static::APP][$this->preference_name]);
+
+		// At type level
+		$this->assertArrayHasKey($this->preference_name, $post_pref->$type[static::APP]);
+		$this->assertEquals($set[$this->preference_name], $post_pref->$type[static::APP][$this->preference_name]);
+
+		$this->assertGreaterThan($log_count, $this->get_log_count(), "Command ($command) did not log");
+	}
+
+	/**
+	 * Try to change an existing preference
+	 *
+	 * We check changing the various combinations with a default set.
+	 * Only forced should give a change.
+	 *
+	 * @dataProvider typeDataProvider
+	 */
+	public function testChangeWithForced($type)
+	{
+		// Set up
+		$log_count = $this->get_log_count();
+		$account = $GLOBALS['egw_info']['user']['account_id'];
+
+		$set = array($this->preference_name => 'Changed '. $type);
+		$old = array($this->preference_name => $type . ' original value');
+
+		$prefs = new Api\Preferences('forced');
+		$prefs->read_repository(false);
+		$prefs->add(static::APP, $this->preference_name, 'forced original value','forced');
+		$prefs->save_repository(false, 'forced');
+
+		$prefs = new Api\Preferences(in_array($type, array('default', 'forced')) ? $type : $account);
+		$prefs->read_repository(false);
+		$prefs->add(static::APP, $this->preference_name, $old[$this->preference_name], $type);
+		$prefs->save_repository(false, $type);
+
+		// Execute
+		$command = new admin_cmd_edit_preferences($account, $type, static::APP, $set, $old);
+		$command->comment = 'Needed for unit test ' . $this->getName();
+		$command->run();
+
+		// Check
+		$post_pref = new Api\Preferences($account);
+		$post = $post_pref->read_repository(false);
+
+		// At user level
+		$this->assertArrayHasKey($this->preference_name, $post[static::APP]);
+		$this->assertEquals($type != 'forced' ? 'forced original value' : $set[$this->preference_name], $post[static::APP][$this->preference_name],
+				"$type preference overrode forced preference"
+		);
+
+		// At type level
+		$this->assertArrayHasKey($this->preference_name, $post_pref->$type[static::APP]);
+		$this->assertEquals($set[$this->preference_name], $post_pref->$type[static::APP][$this->preference_name]);
+
+		$this->assertGreaterThan($log_count, $this->get_log_count(), "Command ($command) did not log");
+	}
+
+	/**
+	 * Try to change an existing preference
+	 *
+	 * We check changing the various combinations, some of which should change
+	 *
+	 * @dataProvider typeChangeDataProvider
+	 */
+	public function testChange($type, $check, $change)
+	{
+		// Set up
+		$log_count = $this->get_log_count();
+		$account = $GLOBALS['egw_info']['user']['account_id'];
+
+
+		$set = array($this->preference_name => $type . ' changed');
+		$old = array($this->preference_name => $type . ' original value');
+		$check_original = $check . ' original value';
+		//echo "\n".__METHOD__ . "($type, $check, $change) Change $type but $check should " . ($change ? '' : 'not ') . "change ( " . ($change ? $set[$this->preference_name] : $check_original).")\n";
+
+		$prefs = new Api\Preferences(in_array($type, array('default', 'forced')) ? $type : $account);
+		$prefs->read_repository(false);
+		$prefs->add(static::APP, $this->preference_name, $old[$this->preference_name], $type);
+		$prefs->save_repository(False, $type);
+
+		$prefs = new Api\Preferences(in_array($check, array('default', 'forced')) ? $check : $account);
+		$prefs->read_repository(false);
+		$prefs->add(static::APP, $this->preference_name, $check_original, $check);
+		$prefs->save_repository(False, $check);
+
+		// Execute
+		$command = new admin_cmd_edit_preferences($account, $type, static::APP, $set, $old);
+		$command->comment = 'Needed for unit test ' . $this->getName();
+		$command->run();
+
+		// Check
+		$post_pref = new Api\Preferences($account);
+		$post = $post_pref->read_repository(false);
+
+		// At type level - should always be what we set
+		$this->assertArrayHasKey($this->preference_name, $post_pref->$type[static::APP]);
+		$this->assertEquals($set[$this->preference_name], $post_pref->$type[static::APP][$this->preference_name]);
+
+		// At user level - depends on type priority
+		$this->assertArrayHasKey($this->preference_name, $post[static::APP]);
+		$this->assertEquals($change ? $set[$this->preference_name] : $check_original, $post[static::APP][$this->preference_name]);
+
+
+		$this->assertGreaterThan($log_count, $this->get_log_count(), "Command ($command) did not log");
+	}
+
+	/**
+	 * Try to delete an existing preference
+	 *
+	 * We check the various combinations, such as deleting a default when the user
+	 * has a value.
+	 *
+	 * @dataProvider typeChangeDataProvider
+	 */
+	public function testDeletePreference($type, $check, $override)
+	{
+		// Set up
+		$log_count = $this->get_log_count();
+		$account = $type == 'group' ? $GLOBALS['egw']->accounts->name2id('Default') : $GLOBALS['egw_info']['user']['account_id'];
+
+		$set = array($this->config_name => null);
+		$old = array($this->config_name => 'It will log whatever');
+
+		$prefs = new Api\Preferences(in_array($type, 'default', 'forced') ? $type : $account);
+		$prefs->add(static::APP, $this->config_name, $old[$this->config_name], in_array($type, array('default', 'forced')) ? $type : 'user');
+		$prefs->save_repository(false, $type);
+
+
+		// Execute
+		$command = new admin_cmd_edit_preferences($account, $type, static::APP, $set, $old);
+		$command->comment = 'Needed for unit test ' . $this->getName();
+		$command->run();
+
+		// Check
+		$account = $check == 'group' ? $GLOBALS['egw']->accounts->name2id('Default') : $GLOBALS['egw_info']['user']['account_id'];
+		$post_pref = new Api\Preferences($account);
+		$post = $post_pref->read_repository();
+
+		// At user level
+		$this->assertEquals($override ? $set[$this->preference_name] : $old[$this->preference_name], $post[static::APP][$this->preference_name]);
+
+		// At type level
+		$this->assertNull($post_pref->$check[static::APP][$this->preference_name]);
+
+		$this->assertGreaterThan($log_count, $this->get_log_count(), "Command ($command) did not log");
+	}
+
+
+	/**
+	 * Give a list of preference levels (types) so we can check them all
+	 * They are in priority order.
+	 */
+	public function typeDataProvider() {
+		return array(
+			['default'],
+			['user'],
+			//['group'], Not really supported yet
+			['forced']
+		);
+	}
+
+	/**
+	 * Get a list of preference levels and if they should be allowed to change
+	 * each other
+	 */
+	public function typeChangeDataProvider() {
+		$levels = array(
+			// Change and this should/should not change
+			['default', 'user',   false],
+			['default', 'forced', false],
+			['user',    'default', true],
+			['user',    'forced', false],
+			['forced',  'user',    true],
+			['forced',  'default', true],
+		);
+
+
+		return $levels;
+	}
+}
\ No newline at end of file