iam new to apex.urgent need of test class for apex class

my apex class

public class MyController {
public ID accountId {get;set;}
  public String email {get;set;}
public String getName() {
return 'MyController';
}
public Opportunity getOpportunity() {
return [select Account.Id, Account.name, Account.G_English_Name__c, Account.B_English_Name__c, Contact__r.name, Contact__r.MailingStreet,Contact__r.MailingCity,
        Contact__r.MailingState, Contact__r.MailingPostalCode, Contact__r.MailingCountry from Opportunity
where id = :ApexPages.currentPage().getParameters().get('id')];
}

public PageReference sendPdf() {

    PageReference pdf = Page.pdfgeneratortemplate;
    // add parent id to the parameters for standardcontroller
    pdf.getParameters().put('id',accountId);
 
    // 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');
    }
 
    Messaging.EmailFileAttachment attach = new Messaging.EmailFileAttachment();
    attach.setContentType('application/pdf');
    attach.setFileName('testPdf.pdf');
    attach.setInline(false);
    attach.Body = body;
 
    Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
    mail.setUseSignature(false);
    mail.setToAddresses(new String[] { 'anand.2861985@gmail.com' });
    mail.setSubject('PDF Email Demo');
    mail.setHtmlBody('Here is the email you requested! Check the attachment!');
    mail.setFileAttachments(new Messaging.EmailFileAttachment[] { attach });
 
    // Send the email
    Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });
 
    ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.INFO, 'Email with PDF sent to '+email));
 
    return null;
 
  }
 
}