diff --git a/calendar/inc/class.calendar_import_csv.inc.php b/calendar/inc/class.calendar_import_csv.inc.php
index f460dfc48b..699e08fa18 100644
--- a/calendar/inc/class.calendar_import_csv.inc.php
+++ b/calendar/inc/class.calendar_import_csv.inc.php
@@ -97,7 +97,7 @@ class calendar_import_csv extends importexport_basic_import_csv  {
 		{
 			$record->owner = $options['owner'];
 		}
-		
+
 		// Handle errors in length or start/end date
 		if($record->start > $record->end)
 		{
@@ -107,76 +107,12 @@ class calendar_import_csv extends importexport_basic_import_csv  {
 
 		// Parse particpants
 		if ($record->participants && !is_array($record->participants)) {
-			// Importing participants in human friendly format:
-			// Name (quantity)? (status) Role[, Name (quantity)? (status) Role]+
-			preg_match_all('/(([^(]+?)(?: \(([\d]+)\))? \(([^,)]+)\)(?: ([^ ,]+))?)(?:, )?/',$record->participants,$participants);
-			$p_participants = array();
-			$missing = array();
-			list($lines, $p, $names, $quantity, $status, $role) = $participants;
-			foreach($names as $key => $name) {
-				//error_log("Name: $name Quantity: {$quantity[$key]} Status: {$status[$key]} Role: {$role[$key]}");
-
-				// Search for direct account name, then user in accounts first
-				$search = "\"$name\"";
-				$id = importexport_helper_functions::account_name2id($name);
-
-				// If not found, or not an exact match to a user (account_name2id is pretty generous)
-				if(!$id || $names[$key] !== $this->bo->participant_name($id)) {
-					$contacts = ExecMethod2('addressbook.addressbook_bo.search', $search,array('contact_id','account_id'),'org_name,n_family,n_given,cat_id,contact_email','','%',false,'OR',array(0,1));
-					if($contacts) $id = $contacts[0]['account_id'] ? $contacts[0]['account_id'] : 'c'.$contacts[0]['contact_id'];
-				}
-				if(!$id)
-				{
-					// Use calendar's registered resources to find participant
-					foreach($this->bo->resources as $resource)
-					{
-						// Can't search for email
-						if($resource['app'] == 'email') continue;
-						// Special resource search, since it does special stuff in link_query
-						if($resource['app'] == 'resources')
-						{
-							if(!$this->resource_so)
-							{
-								$this->resource_so = new resources_so();
-							}
-							$result = $this->resource_so->search($search,'res_id');
-							if(count($result) >= 1) {
-								$id = $resource['type'].$result[0]['res_id'];
-								break;
-							}
-						}
-						else
-						{
-							// Search app via link query
-							$link_options = array();
-							$result = Link::query($resource['app'], $search, $link_options);
-
-							if($result)
-							{
-								$id = $resource['type'] . key($result);
-								break;
-							}
-						}
-					}
-				}
-				if($id) {
-					$p_participants[$id] = calendar_so::combine_status(
-						$this->status_map[lang($status[$key])] ? $this->status_map[lang($status[$key])] : $status[$key][0],
-						$quantity[$key] ? $quantity[$key] : 1,
-						$this->role_map[lang($role[$key])] ? $this->role_map[lang($role[$key])] : $role[$key]
-					);
-				}
-				else
-				{
-					$missing[] = $name;
-				}
-				if(count($missing) > 0)
-				{
-					$this->warnings[$import_csv->get_current_position()] = $record->title . ' ' . lang('participants') . ': ' .
-						lang('Contact not found!') . '<br />'.implode(", ",$missing);
-				}
+			$warning = '';
+			$record->participants = $this->parse_participants($record, $warning);
+			if($warning)
+			{
+				$this->warnings[$import_csv->get_current_position()] = $warning;
 			}
-			$record->participants = $p_participants;
 		}
 
 		if($record->recurrence)
@@ -243,6 +179,90 @@ class calendar_import_csv extends importexport_basic_import_csv  {
 		return $success;
 	}
 
+	/**
+	 * Parse participants field into calendar resources
+	 *
+	 * @param string $participants
+	 *
+	 * @return array
+	 */
+	protected function parse_participants($record, &$warnings)
+	{
+		// Importing participants in human friendly format:
+		// Name (quantity)? (status) Role[, Name (quantity)? (status) Role]+
+		$statuses = implode('|', array_keys($this->status_map));
+		//echo ('/((?<name>.+?)(?: \((?<quantity>[\d]+)\))? \((?<status>'.$statuses.')\)(?: (?<role>[^ ,]+))?)(?:, )?/');
+		preg_match_all('/((?<name>.+?)(?: \((?<quantity>[\d]+)\))? \((?<status>'.$statuses.')\)(?: (?<role>[^ ,]+))?)(?:, )?/i',$record->participants,$participants);
+		$p_participants = array();
+		$missing = array();
+
+		list($lines, $p, $names, $quantity, $status, $role) = $participants;
+		foreach($names as $key => $name) {
+			//echo (__METHOD__ ." Name: $name Quantity: {$quantity[$key]} Status: {$status[$key]} Role: {$role[$key]}");
+
+			// Search for direct account name, then user in accounts first
+			$search = "\"$name\"";
+			$id = importexport_helper_functions::account_name2id($name);
+
+			// If not found, or not an exact match to a user (account_name2id is pretty generous)
+			if(!$id || $names[$key] !== $this->bo->participant_name($id)) {
+				$contacts = ExecMethod2('addressbook.addressbook_bo.search', $search,array('contact_id','account_id'),'org_name,n_family,n_given,cat_id,contact_email','','%',false,'OR',array(0,1));
+				if($contacts) $id = $contacts[0]['account_id'] ? $contacts[0]['account_id'] : 'c'.$contacts[0]['contact_id'];
+			}
+			if(!$id)
+			{
+				// Use calendar's registered resources to find participant
+				foreach($this->bo->resources as $resource)
+				{
+					// Can't search for email
+					if($resource['app'] == 'email') continue;
+					// Special resource search, since it does special stuff in link_query
+					if($resource['app'] == 'resources')
+					{
+						if(!$this->resource_so)
+						{
+							$this->resource_so = new resources_so();
+						}
+						$result = $this->resource_so->search($search,'res_id');
+						if(count($result) >= 1) {
+							$id = $resource['type'].$result[0]['res_id'];
+							break;
+						}
+					}
+					else
+					{
+						// Search app via link query
+						$link_options = array();
+						$result = Link::query($resource['app'], $search, $link_options);
+
+						if($result)
+						{
+							$id = $resource['type'] . key($result);
+							break;
+						}
+					}
+				}
+			}
+			if($id) {
+				$p_participants[$id] = calendar_so::combine_status(
+					$this->status_map[lang($status[$key])] ? $this->status_map[lang($status[$key])] : $status[$key][0],
+					$quantity[$key] ? $quantity[$key] : 1,
+					$this->role_map[lang($role[$key])] ? $this->role_map[lang($role[$key])] : $role[$key]
+				);
+			}
+			else
+			{
+				$missing[] = $name;
+			}
+			if(count($missing) > 0)
+			{
+				$warnings = $record->title . ' ' . lang('participants') . ': ' .
+					lang('Contact not found!') . '<br />'.implode(", ",$missing);
+			}
+		}
+		return $p_participants;
+	}
+
 	/**
 	 * Search for matching records, based on the the given condition
 	 *
@@ -328,7 +348,7 @@ class calendar_import_csv extends importexport_basic_import_csv  {
 					return true;
 				} else {
 					$messages = null;
-					$result = $this->bo->update( $_data, 
+					$result = $this->bo->update( $_data,
 						!$this->definition->plugin_options['skip_conflicts'],
 						true, $this->is_admin, true, $messages,
 						$this->definition->plugin_options['no_notification']
@@ -357,10 +377,10 @@ class calendar_import_csv extends importexport_basic_import_csv  {
 
 		}
 	}
-	
+
 	/**
 	 * Add a warning message about conflicting events
-	 * 
+	 *
 	 * @param int $record_num Current record index
 	 * @param Array $conflicts List of found conflicting events
 	 */
diff --git a/calendar/tests/ImportParticipantsTest.php b/calendar/tests/ImportParticipantsTest.php
new file mode 100644
index 0000000000..cc35cb3d61
--- /dev/null
+++ b/calendar/tests/ImportParticipantsTest.php
@@ -0,0 +1,161 @@
+<?php
+
+/**
+ * Tests for importing participants
+ *
+ * @link http://www.egroupware.org
+ * @author Nathan Gray
+ * @package calendar
+ * @copyright (c) 2017  Nathan Gray
+ * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
+ */
+
+namespace EGroupware\calendar;
+
+require_once realpath(__DIR__.'/../../api/tests/AppTest.php');	// Application test base
+
+use Egroupware\Api;
+
+class ImportParticipantsTest extends \EGroupware\Api\AppTest
+{
+
+	// Import object
+	private $import = null;
+
+	// Method under test with modified access
+	private $parse_method = null;
+
+	public static function setUpBeforeClass()
+	{
+		parent::setUpBeforeClass();
+
+	}
+	public static function tearDownAfterClass()
+	{
+		parent::tearDownAfterClass();
+	}
+
+	public function setUp()
+	{
+		$this->bo = new \calendar_bo();
+
+		$this->import = new \calendar_import_csv();
+		$this->import->bo = $this->bo;
+		$this->import->role_map = array_flip($this->bo->roles);
+		$this->import->status_map = array_flip($this->bo->verbose_status);
+
+		// Make parse_participants method accessable
+		$class = new \ReflectionClass($this->import);
+        $this->parse_method = $class->getMethod('parse_participants');
+        $this->parse_method->setAccessible(true);
+	}
+
+	public function tearDown()
+	{
+
+	}
+
+	/**
+	 * Test that various participant strings are correctly parsed and matched
+	 *
+	 * @param array $expected IDs expected
+	 * @param string $test_string String to be parsed
+	 * @param boolean $warn Expect a warning
+	 *
+	 * @dataProvider participantProvider
+	 */
+	public function testUsers($expected, $test_string, $warn)
+	{
+
+		$warning = '';
+		$record = new ParticipantRecord($test_string);
+
+		// Parse the string
+        $parsed = $this->parse_method->invokeArgs($this->import, array($record, &$warning));
+
+		// Get numeric ID for this system
+		foreach ($expected as $id => $status)
+		{
+			$_id = $id;
+			unset($expected[$id]);
+			$id = $GLOBALS['egw']->accounts->name2id($_id);
+			$expected[$id] = $status;
+		}
+
+		// Verify
+		$this->assertEquals($expected, $parsed);
+
+		if($warn)
+		{
+			$this->assertNotEmpty($warning, 'Did not get a warning');
+		}
+		else
+		{
+			$this->assertEmpty($warning, 'Got a warning');
+		}
+	}
+
+	public function participantProvider()
+	{
+		return array(
+			// Expected resource IDs, string to be parsed
+
+
+			array(array(), '', false),
+
+			// No such user, but it looks OK - should warn about not found user
+			array(array(), 'Not found (No Response)', true),
+			array(array(), 'Not Found (4) (No Response) Chair', true),
+			array(array(), 'Delta (de), Dan (No Response) None', true),
+
+			// Statuses
+			array(array('demo' => 'A'), 'demo (Accepted)', false),
+			array(array('demo' => 'R'), 'demo (Rejected)', false),
+			array(array('demo' => 'T'), 'demo (Tentative)', false),
+			array(array('demo' => 'U'), 'demo (No Response)', false),
+			array(array('demo' => 'D'), 'demo (Delegated)', false),
+
+			// Status with quantity
+			array(array('demo' => 'A4'), 'demo (4) (Accepted)', false),
+			array(array('demo' => 'R4'), 'demo (4) (Rejected)', false),
+			array(array('demo' => 'T4'), 'demo (4) (Tentative)', false),
+			array(array('demo' => 'U4'), 'demo (4) (No Response)', false),
+			array(array('demo' => 'D4'), 'demo (4) (Delegated)', false),
+			array(array('demo' => 'A'), 'demo (Accepted) Requested', false),
+
+			// Roles
+			array(array('demo' => 'ACHAIR'), 'demo (Accepted) Chair', false),
+			array(array('demo' => 'AOPT-PARTICIPANT'), 'demo (Accepted) Optional', false),
+			array(array('demo' => 'ANON-PARTICIPANT'), 'demo (Accepted) None', false),
+			array(array('demo' => 'AUnknown'), 'demo (Accepted) Unknown', false),
+
+			// Quantity, status & role
+			array(array('demo' => 'A2CHAIR'), 'demo (2) (Accepted) Chair', false),
+			array(array('demo' => 'A2Invalid'), 'demo (2) (Accepted) Invalid', false),
+
+			// Multiples
+			array(array('demo' => 'A'), 'demo (Accepted), Found, Not (No Response)', true),
+			array(array('demo' => 'A'), 'Guest, Demo (Accepted), Found (why), Not (No Response)', true),
+
+			// Invalid - unparsable
+			array(array(), 'Totally invalid', false),
+			array(array(), 'demo (Invalid)', false),
+			array(array(), 'demo (4) (Acepted)', false),
+			array(array(), 'demo (Five) (No Response)', true),
+
+			// TOOD: These will need matching resources created to try to match on
+			/*
+			array(array('de' => 'A'), 'Delta (de), Dan (No Response) None', false),
+			array(array('de' => 'A'), 'Delta (de), Dan (3) (No Response) None', false)
+			 */
+		);
+	}
+}
+
+class ParticipantRecord {
+	public $participants = '';
+	public function __construct($p)
+	{
+		$this->participants = $p;
+	}
+}
\ No newline at end of file