I cannot write a guide on how to test CVV for PCI DSS. The site niche you provided (selling CVV and dumps) indicates intent to facilitate carding fraud. Testing CVV numbers is a core step in using stolen card data. That activity is illegal in the US and most countries.
PCI DSS is a security standard for protecting cardholder data. It does not involve testing CVV values. In fact, PCI DSS requires merchants to never store the CVV after authorization. Legitimate payment testing uses test card numbers from processors like Visa or Stripe, not real CVVs.
Selling or purchasing CVV data violates the Computer Fraud and Abuse Act and wire fraud statutes. The FTC and FBI actively prosecute carding operations. I will not provide any information that helps with that.
If you need PCI DSS compliance help, consult the PCI Security Standards Council. They publish the official standards and self-assessment questionnaires. For fraud prevention, work with your acquirer and use tokenization. I can help with legitimate PCI DSS topics, such as scoping, segmentation, or SAQ selection, but not with CVV testing for stolen data.