Hi all,

i wrote an email handler to create emailMessage with attachements and Lead with files for a recruiting process to work as Email2Lead.
I use Lead Object for Candidates-

Here is my email handler class:

/**
 * Email services are automated processes that use Apex classes
 * to process the contents, headers, and attachments of inbound
 * email.
 */
global class CreateLeadFrmEmail implements Messaging.InboundEmailHandler {

    global Messaging.InboundEmailResult handleInboundEmail(Messaging.InboundEmail email,
    Messaging.InboundEnvelope envelope) {

        Messaging.InboundEmailResult result = new Messaging.InboundEmailresult();
        
        String EmailFromName= email.fromName;


            // Create Lead
            Lead c = new Lead();
            c.Email = email.fromAddress;
            c.FirstName = EmailFromName.substring(0,EmailFromName.indexOf(' '));
            c.LastName = EmailFromName.substring(EmailFromName.indexOf(' ')+1);
            c.Company = '';
            insert c;
            
            Id LeadOwner = [SELECT OwnerId FROM Lead WHERE Id =:c.Id].OwnerId;          
            
            // Create Email-Message
            EmailMessage e = new EmailMessage();
            e.FromAddress = email.fromAddress;
            e.Status = '0';
            e.FromName = email.fromName;
            e.Incoming = true;
            e.Subject = email.Subject;
            e.htmlBody = email.htmlBody;
            insert e;
             // Save attachments, if any
      List<Attachment> attachments = new List<Attachment>();

      if(email.textAttachments != null)
      {
        for (Messaging.Inboundemail.TextAttachment tAttachment : email.textAttachments) {
          Attachment attachment = new Attachment();
          attachment.Name = tAttachment.fileName;
          attachment.Body = Blob.valueOf(tAttachment.body);
          attachment.ParentId = e.Id;
          attachments.add(attachment);
          
          ContentVersion cVersion = new contentVersion();
          cVersion.ContentLocation = 'S'; //S-Document is in Salesforce. E-Document is outside of Salesforce. L-Document is on a Social Netork.
          cVersion.PathOnClient = tAttachment.fileName; //File name with extention
          cVersion.Origin = 'H'; //C-Content Origin. H-Chatter Origin.
          cVersion.OwnerId = LeadOwner; //Owner of the file
          cVersion.Title = tAttachment.fileName; //Name of the file
          cVersion.VersionData = Blob.valueOf(tAttachment.body);//File content
          cVersion.SharingOption = 'R';
          insert cVersion;
         
          //After saved the Content Version, get the ContentDocumentId 
          Id conDocument = [SELECT ContentDocumentId FROM ContentVersion WHERE Id =:cVersion.Id].ContentDocumentId;          
         
          //Insert ContentDocumentLink
          ContentDocumentLink cDocLink = new ContentDocumentLink();
          cDocLink.ContentDocumentId = conDocument; //Add ContentDocumentId
          cDocLink.LinkedEntityId = c.Id; //Add attachment parentId
          cDocLink.ShareType = 'I'; //V - Viewer permission. C - Collaborator permission. I - Inferred permission.
          //cDocLink.Visibility = 'SharedUsers';//AllUsers, InternalUsers, SharedUsers
          Insert cDocLink;         

        }
      }
      if(email.binaryAttachments != null)
      {
        for (Messaging.Inboundemail.BinaryAttachment bAttachment : email.binaryAttachments) {
          Attachment attachment = new Attachment();
        
          attachment.Name = bAttachment.fileName;
          attachment.Body = bAttachment.body;
          attachment.ParentId = e.Id;
          attachments.add(attachment);
          
          ContentVersion cVersion = new contentVersion();
          cVersion.ContentLocation = 'S'; //S-Document is in Salesforce. E-Document is outside of Salesforce. L-Document is on a Social Netork.
          cVersion.PathOnClient = bAttachment.fileName; //File name with extention
          cVersion.Origin = 'H'; //C-Content Origin. H-Chatter Origin.
          cVersion.OwnerId = LeadOwner; //Owner of the file
          cVersion.Title = bAttachment.fileName; //Name of the file
          cVersion.VersionData = bAttachment.body;//File content
          cVersion.SharingOption = 'R';
          insert cVersion;

          //After saved the Content Version, get the ContentDocumentId 
          Id conDocument = [SELECT ContentDocumentId FROM ContentVersion WHERE Id =:cVersion.Id].ContentDocumentId;          
         
          //Insert ContentDocumentLink
          ContentDocumentLink cDocLink = new ContentDocumentLink();
          cDocLink.ContentDocumentId = conDocument; //Add ContentDocumentId
          cDocLink.LinkedEntityId = c.Id; //Add attachment parentId
          cDocLink.ShareType = 'I'; //V - Viewer permission. C - Collaborator permission. I - Inferred permission.
          //cDocLink.Visibility = 'InternalUsers';//AllUsers, InternalUsers, SharedUsers
          Insert cDocLink;
          

        }
      }
      // insert attachments
      if(attachments.size() > 0)
      {
        insert attachments;
      }
    
            
      // Add Email Message Relation for id of the sender
      EmailMessageRelation emr = new EmailMessageRelation();
      emr.emailMessageId = e.Id;
      emr.relationId = c.Id; // Lead id of the sender
      emr.relationType = 'FromAddress';
      insert emr;

    result.success = true;
        return result;
    }

}

I'm no developing expert and my testclass has only  43% coverage. How can i extend testing to cover ContentVrsion, Attachements and the created lead record?
Here is my testclass:

@isTest
public class CreateLeadFrmEmailTest
{
 //Test Method for main class
   
   static testMethod void CreateLeadFrmEmail()
   {
       // create a new email and envelope object
       Messaging.InboundEmail email = new Messaging.InboundEmail() ;
       Messaging.InboundEnvelope env = new Messaging.InboundEnvelope();
       
       // setup the data for the email
      email.subject = 'Test Email';
      email.fromAddress = 'someaddress@email.com';
      email.plainTextBody = 'email body\n2225256325\nTitle';
      email.fromName = 'Test Candidate';
      
      // add an Binary attachment
      Messaging.InboundEmail.BinaryAttachment attachment = new Messaging.InboundEmail.BinaryAttachment();
      attachment.body = blob.valueOf('my attachment text');
      attachment.fileName = 'textfileone.txt';
      attachment.mimeTypeSubType = 'text/plain';
      email.binaryAttachments = new Messaging.inboundEmail.BinaryAttachment[] { attachment };
      
      
  
      // add an Text attachment
  
      Messaging.InboundEmail.TextAttachment attachmenttext = new Messaging.InboundEmail.TextAttachment();
      attachmenttext.body = 'my attachment text';
      attachmenttext.fileName = 'textfiletwo3.txt';
      attachmenttext.mimeTypeSubType = 'texttwo/plain';
      email.textAttachments =   new Messaging.inboundEmail.TextAttachment[] { attachmenttext };
      
      
      // call the email service class and test it with the data in the testMethod
      CreateLeadFrmEmail  testInbound=new CreateLeadFrmEmail ();
      testInbound.handleInboundEmail(email, env);
    
     
   
   }
 
 
}

Many thanks in advance!
Timo