Elgg\SystemMessagesService::count PHP Method

    public function count($register_name = "")
    {
        $set = $this->loadRegisters();
        $count = 0;
        foreach ($set as $prop => $values) {
            if ($register_name === $prop || $register_name === '') {
                $count += count($values);
            }
        }
        return $count;
    }

 function testCanCount()
 {
     $this->svc->addSuccessMessage(['s2', 's3']);
     $this->svc->addErrorMessage(['e1', 'e2', 'e3']);
     $this->assertEquals(2, $this->svc->count("success"));
     $this->assertEquals(3, $this->svc->count("error"));
     $this->assertEquals(5, $this->svc->count());
 }