I\'m new to cURL in PHP. I have a question regarding usage of curl options.
Consider two script files: test1.php and test2.php both present in root
You are correct. CURLOPT_POSTFIELDS implies CURLOPT_POST. You don't need to use CURLOPT_POST while using CURLOPT_POSTFIELDS. The request method will always be set to POST in this case.
Note that this is in your case as long as you want it to be a POST request.
If you don't want to be it a POST request but set CURLOPT_POSTFIELDS, please see this related Q&A: