hi guys im new for writing test class

heelp me writting test class for this class

public  class GetImageHandler {

    public GetImageHandler() {

    }
    
   Contact c= new Contact(); 
     public void save(){
    
      c.LastName='hemant';
     c.Email='jaguu@juglee.com';
     insert c;
     Send();
     }

     public void de(){
    
      delete c;
     }

    public final Opportunity Op;

    Opportunity opp = new Opportunity();
    
    public Id parentId;
    
         public GetImageHandler(ApexPages.StandardController controller) {
    
                parentId= ApexPages.currentPage().getParameters().get('id');
                
                opp = [Select Name,Id,Primary_Contact__r.Email from Opportunity where Id=: parentId];
    
    }
   public PageReference savePdf() {

    PageReference pdf = Page.quote;
    // add parent id to the parameters for standardcontroller
    pdf.getParameters().put('id',parentId);

    // create the new attachment
    Attachment attach = new Attachment();

    // the contents of the attachment from the pdf
    Blob body;

    try {

        // returns the output of the page as a PDF
        body = pdf.getContent();

    // need to pass unit test -- current bug    
    } catch (VisualforceException e) {
        body = Blob.valueOf('Some Text');
    }

    attach.Body = body;
    // add the user entered name
    attach.Name = 'Quote_'+opp.Name+'_'+System.Today().year()+'.pdf';
    attach.IsPrivate = false;
    // attach the pdf to the account
    attach.ParentId = parentId;
    insert attach;
   save();
    // send the user to the account to view results
    return new PageReference('https://c.cs14.visual.force.com/'+parentId);

  }
    
   public PageReference saveExl() {

    PageReference pdf = Page.quoteexl;
    // add parent id to the parameters for standardcontroller
    pdf.getParameters().put('id',parentId);

    // create the new attachment
    Attachment attach = new Attachment();

    // the contents of the attachment from the pdf
    Blob body;

    try {

        // returns the output of the page as a PDF
        body = pdf.getContent();

    // need to pass unit test -- current bug    
    } catch (VisualforceException e) {
        body = Blob.valueOf('Some Text');
    }

    attach.Body = body;
    // add the user entered name
    attach.Name = 'Quote_'+opp.Name+'_'+System.Today().year()+'.xls';
    attach.IsPrivate = false;
    // attach the pdf to the account
    attach.ParentId = parentId;
    insert attach;
    Save();
    // send the user to the account to view results
    return new PageReference('https://c.cs14.visual.force.com/'+parentId);

  }
  
 public PageReference send() {
                Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage(); 
                String addresses;
                if (opp.Primary_Contact__r.Email!= null) {
                    addresses = opp.Primary_Contact__r.Email;
                
                }
                  email.setTargetObjectId(c.id);
                  email.setWhatId(Opp.id);
                  //email.setTemplateId('00X28000000QK5V');
                  email.setSubject('Revised Quote');
                  email.setToAddresses(new String[] { addresses });
               // email.setToAddress(addresses);
                  email.setPlainTextBody( 'Please Find Attachment');
        
                
                    
                     List<Messaging.Emailfileattachment> fileAttachments = new List<Messaging.Emailfileattachment>();
                       // for (Attachment a : [select Name, Body, BodyLength from Attachment where ParentId = :opp.Id])
                     //   {
                        // Add to attachment file list
                        List<Attachment> a = [select Name, Body, BodyLength from Attachment where ParentId = :opp.Id Order by Createddate desc Limit 1];
                        Messaging.Emailfileattachment efa = new Messaging.Emailfileattachment();
                        efa.setFileName(a[0].Name);
                        efa.setBody(a[0].Body);
                        fileAttachments.add(efa);
                       // }
                        email.setFileAttachments(fileAttachments);
                      //Send email
                        Messaging.sendEmail(new Messaging.SingleEmailMessage[] { email });
       
         
                de();

                return new PageReference('https://c.cs14.visual.force.com/'+parentId);
            }
 
}