Generate Quote PDF via Salesforce REST API

QuotePDFGenerator.apex

global class QuotePDFGenerator {
  
  @future(callout=true)
    public static void AttachPDFToQuote(String Id) {
        try {
            CreateQuoteDocumentFromPDF(Id);
        } catch(exception ex) {
            System.debug('Error: ' + ex);
        }
    }
    
    public static String CreateQuoteDocumentFromPDF(String Id) {
        String quoteURL = '/quote/quoteTemplateDataViewer.apexp?headerHeight=156&footerHeight=94&summlid=0EH800000000fkT&id=' + Id;
        Blob renderedPDF;
        if (Test.isRunningTest()) {
            renderedPDF = Blob.valueOf('Unit.Test');
        } else {
            renderedPDF = new PageReference(quoteURL).getContentAsPDF();
        }
        QuoteDocument doc = new QuoteDocument(QuoteId = Id, Document = renderedPDF);
        INSERT doc;
        String Name = [select Name from QuoteDocument where QuoteId =: Id].Name;
        RETURN Name;
    }
    
}

QuotePDFGeneratorResource.apex

@RestResource(urlMapping='/Quote/PDFGenerator/*')
global with sharing class QuotePDFGeneratorResource {
  
  @HttpPost
    global static String doPost(String Id) {
        QuotePDFGenerator.AttachPDFToQuote(Id);
        return 'SUCCESS';
    }
    
}

Test_QuotePDFGenerator.apex

@isTest

private class Test_QuotePDFGenerator {

    static Account account;
    static Opportunity opportunity;
    static Quote quote;

    static {

        account = new Account(
            Name = 'Test Account'
        );
        insert account;

        opportunity = new Opportunity(
            AccountId = account.Id,
            Name = account.Name,
            StageName = 'Prospecting',
            CloseDate = System.today()
        );
        insert opportunity;

        quote = new Quote(
            Name = '12345', 
            OpportunityId = opportunity.Id
        );
        insert quote;

    }

    static testMethod void test_AttachPDFToQuote() {

        Test.startTest();
        QuotePDFGenerator.AttachPDFToQuote(quote.Id);
        Test.stopTest(); 
        
        Integer count = [select count() from QuoteDocument where QuoteId =: quote.Id];
        System.assertEquals(1, count);

    }
    
    static testMethod void test_CreateQuoteDocumentFromPDF() {

        Test.startTest();

        Integer beforeCount = [select count() from QuoteDocument where QuoteId =: quote.Id];
        System.debug('BeforeCount: ' + beforeCount);
        System.assertEquals(0, beforeCount);
        
        String Name = QuotePDFGenerator.CreateQuoteDocumentFromPDF(quote.Id);
        String ExpectedName = [select Name from QuoteDocument where QuoteId =: quote.Id].Name;
        
        System.assertEquals(ExpectedName, Name);
    
        Test.stopTest(); 

    }
}

Test_QuotePDFGeneratorResource.apex

@isTest

private class Test_QuotePDFGeneratorResource {
    
    static testMethod void testQuotePdfGeneratorResource() {
        Test.startTest();        
        String result = QuotePDFGeneratorResource.doPost('abc123');
        System.assertEquals('SUCCESS', result);        
        Test.stopTest();
    }

}