Trigger Handler not throwing errors or reading SOQL query correctly

Question

When the trigger is called, I'm looking to pass the Trigger.new list into the ContactTriggerHandler class, and then filter on that list to be a certain record type and associated with an Account Contact Relationship (AccountContactRelation object) that has a certain role. This compiles but is not triggering any of the error codes. I passed con directly to the for loop and it works as intended (doesn't check relationships or record type however), so I'm thinking that it may be the SOQL query. When I run the test, I only get 63% code coverage (image below). Trigger

trigger ContactTrigger on Contact (before update) {
    if(trigger.isbefore){
        if(trigger.isupdate){
          ContactTriggerHandler.IsPricingLetter(Trigger.new);
                            }//End If IsUpdate          
                   }//End If IsBefore
   }//End Class

Class

public class ContactTriggerHandler {
    public static void IsPricingLetter(List<Contact> con){
                            
       List<Contact> ContactLookup = [SELECT id,mailingstreet,mailingcity,mailingstate,mailingpostalcode,mailingcountry,email,active_contact__c                                     
                                       FROM contact WHERE id IN :con 
                                       AND id IN (SELECT Contactid 
                                                  FROM accountcontactrelation
                                                  WHERE roles INCLUDES (:label.messer_US_Pricing_Letter) AND isactive=true)
                                       AND Recordtypeid='0125b0000015OkJAAU'
                                      ];
            
          for(Contact CheckContact : ContactLookup){
                          if(CheckContact.MailingStreet==null){
                          CheckContact.MailingStreet.addError(label.Messer_US_Contact_Street+' on a '+label.messer_US_Pricing_Letter+' Contact cannot be null.'); 
                                }//End If Mailing Street   
                          if(CheckContact.MailingCity==null){
                          CheckContact.MailingCity.addError(label.Messer_US_Contact_City+' on a '+label.messer_US_Pricing_Letter+' Contact cannot be null.'); 
                                }//End If Mailing City
                          if(CheckContact.MailingState==null){
                          CheckContact.MailingState.addError(label.Messer_US_Contact_State+' on a '+label.messer_US_Pricing_Letter+' Contact cannot be null.'); 
                                }//End If Mailing State 
                          if(CheckContact.MailingPostalCode==null){
                          CheckContact.MailingPostalCode.addError(label.Messer_US_Contact_Postal_Code+' on a '+label.messer_US_Pricing_Letter+' Contact cannot be null.'); 
                                }//End If Mailing Postal Code 
                          if(CheckContact.MailingCountry==null){
                          CheckContact.MailingCountry.addError(label.Messer_US_Contact_Country+' on a '+label.messer_US_Pricing_Letter+' Contact cannot be null.'); 
                                }//End If Mailing Country
                          if(CheckContact.Email==null){
                          CheckContact.Email.addError(label.Messer_US_Contact_Email+' on a '+label.messer_US_Pricing_Letter+' Contact cannot be null.'); 
                                }//End If Email
                          if(CheckContact.Active_Contact__c==false){
                          CheckContact.active_contact__c.addError('A Contact with an active '+label.messer_US_Pricing_Letter+' relationship cannot be made inactive.'); 
                                }//End If Active
                                                 }//end for loop
                               
    }//end isPricingLetter method
}//End Class

Test Class

@isTest
public class ContactTriggerHandlerTest {

    public static Account getAccount(){
        ccrz__E_AccountGroup__c accountgroupObj = new ccrz__E_AccountGroup__c(Name = 'Messer Base',
                                                                              CurrencyIsoCode = 'USD',
                                                                              ccrz__PriceListSelectionMethod__c = 'Best Price');
        insert accountgroupObj;
        account a = new account(name='DevTest Account',Type='Prospect',Industry='Chemistry & Energy',
                                              ccrz__E_AccountGroup__C=accountgroupobj.id);

        insert a;
        return a;
    }//End getAccount
    public static Contact getContact(){
        Account a = getAccount();
        contact c = new contact(firstname = 'TestFirstName',active_contact__c=true,lastname = 'TestLastName',mailingstreet = 'Test Street',mailingcity = 'Test City',
                                mailingState = 'Test State',mailingPostalCode = '99999',mailingCountry = 'US',email = '[email protected]',accountid=a.id
                               ,recordtypeid='0125b0000015OkJAAU');//CRM Contact US Record Type
        insert c;
        return c;      

    }//End getContact
    static testmethod void updateStreetWithPricingLettersRelationship(){
        Contact c = getContact();
        Account a = getAccount();
        
        accountcontactrelation acr = new accountcontactrelation(accountid=a.id,contactid = c.id,Roles = label.messer_US_Pricing_Letter,isActive=true);
        insert acr;     
         
        try{
        c.mailingstreet='';
               update c;
        }catch(DMLException e){
            System.debug(e);
        }finally{
            System.debug('Mailing Street Checked!');
                }
 
        }//End updateStreetwithRelationship
     static testmethod void updateCityWithPricingLettersRelationship(){
        Contact c = getContact();
        Account a = getAccount();
        
        accountcontactrelation acr = new accountcontactrelation(accountid = a.Id,contactid = c.id,Roles = label.messer_US_Pricing_Letter,isActive=true);
        insert acr;  
         
        try{
         c.mailingcity='';
        update c;
        }catch(DMLException e){
            System.debug(e);
        }finally{
            System.debug('Mailing City Checked!');
                }
        
    }//End updateCitywithRelationship
    static testmethod void updateStateWithPricingLettersRelationship(){
        Contact c = getContact();
        Account a = getAccount();
        
        accountcontactrelation acr = new accountcontactrelation(accountid = a.Id,contactid = c.id,Roles = label.messer_US_Pricing_Letter,isActive=true);
        insert acr;  
        
        try{
        c.MailingState='';
        update c;
        }catch(DMLException e){
            System.debug(e);
        }
        finally{
            System.debug('Mailing State Checked!');
                }
    }//End updateStatewithRelationship
    static testmethod void updatePostalCodeWithPricingLettersRelationship(){
        Contact c = getContact();
        Account a = getAccount();
        
        accountcontactrelation acr = new accountcontactrelation(accountid = a.Id,contactid = c.id,Roles = label.messer_US_Pricing_Letter,isActive=true);
        insert acr;   
        
        try{
        c.MailingPostalCode='';
        update c;
        }catch(DMLException e){
            System.debug(e);
        }
        finally{
            System.debug('Mailing Postal Code Checked!');
                }
    }//End updatePostalCodewithRelationship
    static testmethod void updateCountryWithPricingLettersRelationship(){
        Contact c = getContact();
        Account a = getAccount();
        
        accountcontactrelation acr = new accountcontactrelation(accountid = a.Id,contactid = c.id,Roles = label.messer_US_Pricing_Letter,isActive=true);
        insert acr;  
        
        try{
        c.MailingCountry='';
        update c;
        }catch(DMLException e){
            System.debug(e);
        }finally{
            System.debug('Mailing Country Checked!');
                }
        
    }//End updateCountrywithRelationship
    static testmethod void updateEmailWithPricingLettersRelationship(){
        Contact c = getContact();
        Account a = getAccount();
        
        accountcontactrelation acr = new accountcontactrelation(accountid = a.Id,contactid = c.id,Roles = label.messer_US_Pricing_Letter,isActive=true);
        insert acr;  
        
        try{
        c.Email='';
        update c;
        }catch(DMLException e){
            System.debug(e);
        }finally{
            System.debug('Email Checked!');
                }
        
    }//End updateEmailwithRelationship
    static testmethod void DeactivateContactAttempt(){
        Contact c = getContact();
        Account a = getAccount();
        
        accountcontactrelation acr = new accountcontactrelation(accountid = a.Id,contactid = c.id,Roles = label.messer_US_Pricing_Letter,isActive=true);
        insert acr;  
        
        try{
        c.Active_Contact__c=false;
        update c;
        }catch(DMLException e){
            System.debug(e);
        }finally{
            System.debug('Active Contact? Checked!');
                }
        
    }//End updateEmailwithRelationship

}//End Class

Answer 1

Mate, I gave you a decent answer in https://stackoverflow.com/a/75140042/313628

I explained that your stuff doesn't run OK because you're running a loop over what you queried from database - over old values, from before save action you're intercepting now. Nothing you're updating "right now" in the trigger is checked in that loop. In fact it's extra dummy because if user inserts a Contact with empty address - your thing will happily prevent them from ever fixing that.

Then we had https://stackoverflow.com/a/75188127/313628

And now this... So yeah, technically I suspect this will give you coverage:

Contact c = new Contact(AccountId = '...', LastName = 'whatev'); // yes, empty address
insert c;
insert new AccountContactRelation(...);
try{
    c.MailingStreet = c.MailingCity = c.MailingCountry = c.MailingPostalCode = 'unimportant';
    update c;
} catch(Exception e){
    System.assert(e.getMessage().contains(Label.Messer_US_Contact_Street));
    // Oops, this throws even when I'm trying to fix the missing data!
}

Don't deploy this to production, you'll brick your system...