USER_DEBUG [21]|DEBUG|ev: (EscrowValidator__mdt:{Username__c=Test, Pass__c=123, Acces_granted__c=false, Token__c=123456, Id=m000U00000002tNQAQ})

USER_DEBUG [25]|DEBUG|pageRef: System.PageReference[/apex/escrowlink?token=123456]

DEBUG|An exception accId occurred: List has no rows for assignment to SObject

public without sharing class Escrowlink{
    public List<ContentDistribution> urlsContentDistribution {get;set;}
    public map<string,string> urlmap{get;set;}
    public Id accId;
    public Escrowlink(Apexpages.StandardController con){
                urlsContentDistribution = new List<ContentDistribution>();
                urlmap = new map<string,string>();
        try{
            string token = apexpages.currentpage().getparameters().get('token');
            accId  = [SELECT id , Token__c FROM Account WHERE Token__c =:token LIMIT 1].id;
        }
        catch(Exception e){
            System.debug('An exception accId occurred: ' + e.getMessage());
        }
        try{
           urlsContentDistribution = [SELECT DistributionPublicUrl, ContentDownloadURL ,name FROM ContentDistribution WHERE RelatedRecordId = :accId];
            for(ContentDistribution m:urlsContentDistribution){
                urlmap.put(m.name,m.DistributionPublicUrl);
            }
        }
        catch(Exception e){
            System.debug('An exception idsContentdocument occurred : ' + e.getMessage());
        }
    }
}

@istest
public class EscrowLinkTest {
    static testmethod void escrowlinktest(){
        EscrowLogin.testCase = 'Unittest1';
        Account acc = new Account(Name='accounttest',Token__c='123456');
        insert acc;

        ContentVersion cv=new Contentversion();
        cv.title='ABC';
        cv.PathOnClient ='test';
        Blob b=Blob.valueOf('Unit Test Attachment Body');
        cv.versiondata=EncodingUtil.base64Decode('Unit Test Attachment Body');
        insert cv;

        ContentDistribution contentdist = new ContentDistribution(Name='contentdist',RelatedRecordId = acc.id, ContentVersionId= cv.id);
        insert contentdist;

        List<EscrowValidator__mdt> ev = [SELECT Username__c , Pass__c, Acces_granted__c, Token__c
                                         FROM EscrowValidator__mdt
                                         WHERE Unittest__c = :EscrowLogin.testCase];
        system.debug('ev: '+ev);

        PageReference pageRef = Page.EscrowLink;
        pageRef.getParameters().put('token',ev[0].Token__c);
        system.debug('pageRef: '+pageRef);

        Apexpages.StandardController sc = new Apexpages.standardController(acc);
        EscrowLink ext = new EscrowLink(sc);
        system.debug('sc: '+sc);

        System.assertEquals(ext.urlmap.get(contentdist.DistributionPublicUrl), contentdist.DistributionPublicUrl);
    }
}