Piwik\Plugins\UsersManager\API::getUserPreference PHP Method

    public function getUserPreference($userLogin, $preferenceName)
    {
        Piwik::checkUserHasSuperUserAccessOrIsTheUser($userLogin);
        $optionValue = $this->getPreferenceValue($userLogin, $preferenceName);
        if ($optionValue !== false) {
            return $optionValue;
        }
        return $this->getDefaultUserPreference($preferenceName, $userLogin);
    }

 public function testGetUserPreferenceDefault()
 {
     $this->addSites(1);
     $defaultReportPref = API::PREFERENCE_DEFAULT_REPORT;
     $defaultReportDatePref = API::PREFERENCE_DEFAULT_REPORT_DATE;
     $this->assertEquals(1, $this->api->getUserPreference('someUser', $defaultReportPref));
     $this->assertEquals('yesterday', $this->api->getUserPreference('someUser', $defaultReportDatePref));
 }