Add missing mock result for getGroupMembers

getGroupMembers did not return any results from the mock so the called
would get null.

Fixes issue with PHP 7.2 where calling count() with null fails.

tests/unit/Dav/MembershipNodeTest.php

@@ -141,7 +141,8 @@ public function testNodeName() {
 	}
 
 	public function testDeleteAsAdmin() {
-		$this->setCurrentUserMemberInfo(['group_id' => 1, 'user_id' => self::CURRENT_USER, 'role' => CustomGroupsDatabaseHandler::ROLE_ADMIN]);
+		$memberInfo = ['group_id' => 1, 'user_id' => self::CURRENT_USER, 'role' => CustomGroupsDatabaseHandler::ROLE_ADMIN];
+		$this->setCurrentUserMemberInfo($memberInfo);
 		$this->handler->expects($this->once())
 			->method('removeFromGroup')
 			->with(self::NODE_USER, 1)
@@ -155,6 +156,13 @@ public function testDeleteAsAdmin() {
 				['group_id' => 1, 'user_id' => self::NODE_USER, 'role' => CustomGroupsDatabaseHandler::ROLE_ADMIN]
 			);
 
+		$searchAdmins = new Search();
+		$searchAdmins->setRoleFilter(CustomGroupsDatabaseHandler::ROLE_ADMIN);
+		$this->handler->expects($this->once())
+			->method('getGroupMembers')
+			->with(1, $searchAdmins)
+			->willReturn([$memberInfo]);
+
 		$called = array();
 		\OC::$server->getEventDispatcher()->addListener('\OCA\CustomGroups::removeUserFromGroup', function ($event) use (&$called) {
 			$called[] = '\OCA\CustomGroups::removeUserFromGroup';
@@ -173,12 +181,20 @@ public function testDeleteAsAdmin() {
 	 * @expectedException \Sabre\DAV\Exception\PreconditionFailed
 	 */
 	public function testDeleteAsAdminFailed() {
-		$this->setCurrentUserMemberInfo(['group_id' => 1, 'user_id' => self::CURRENT_USER, 'role' => CustomGroupsDatabaseHandler::ROLE_ADMIN]);
+		$memberInfo = ['group_id' => 1, 'user_id' => self::CURRENT_USER, 'role' => CustomGroupsDatabaseHandler::ROLE_ADMIN];
+		$this->setCurrentUserMemberInfo($memberInfo);
 		$this->handler->expects($this->once())
 			->method('removeFromGroup')
 			->with(self::NODE_USER, 1)
 			->willReturn(false);
 
+		$searchAdmins = new Search();
+		$searchAdmins->setRoleFilter(CustomGroupsDatabaseHandler::ROLE_ADMIN);
+		$this->handler->expects($this->once())
+			->method('getGroupMembers')
+			->with(1, $searchAdmins)
+			->willReturn([$memberInfo]);
+
 		$this->node->delete();
 	}
 
@@ -239,6 +255,13 @@ public function testDeleteSelfAsNonAdmin() {
 			->with(self::NODE_USER, 1)
 			->willReturn(true);
 
+		$searchAdmins = new Search();
+		$searchAdmins->setRoleFilter(CustomGroupsDatabaseHandler::ROLE_ADMIN);
+		$this->handler->expects($this->once())
+			->method('getGroupMembers')
+			->with(1, $searchAdmins)
+			->willReturn([['uid' => 'adminuser']]);
+
 		// no notification in this case
 		$this->helper->expects($this->never())
 			->method('notifyUserRemoved');
@@ -271,6 +294,13 @@ public function testDeleteAsSuperAdmin() {
 			->with(self::NODE_USER, 1)
 			->willReturn(true);
 
+		$searchAdmins = new Search();
+		$searchAdmins->setRoleFilter(CustomGroupsDatabaseHandler::ROLE_ADMIN);
+		$this->handler->expects($this->once())
+			->method('getGroupMembers')
+			->with(1, $searchAdmins)
+			->willReturn([['uid' => 'adminuser']]);
+
 		$this->node->delete();
 	}