How to mock DNS CAA record lookups in Python

import dnslib

def parse_caa_record(record_string):
    """Parse a DNS CAA record string into its components."""
    parts = record_string.split()
    flags = int(parts[0])
    tag = parts[1]
    value = parts[2]
    return flags, tag, value

def mock_caa_lookup(domain, caa_records):
    """Mock DNS CAA lookup that returns a filtered list of CAA records."""
    records = caa_records.get(domain, [])
    results = []
    for record in records:
        flags, tag, value = parse_caa_record(record)
        # Only return records that are allowed for lookup (simplified logic)
        if flags == 0 and tag in ("issue", "issuewild", "iodef"):
            results.append((tag, value, flags))
    return results

if __name__ == "__main__":
    # Mock DNS zone data
    zone_data = {
        "example.com": [
            "0 issue \"letsencrypt.org\"",
            "0 issuewild \"comodoca.com\"",
            "0 iodef \"mailto:security@example.com\"",
            "128 issue \"untrusted-ca.org\""  # This one should be filtered out
        ]
    }
    
    domain = "example.com"
    print(f"CAA records for {domain}:")
    for tag, value, flags in mock_caa_lookup(domain, zone_data):
        print(f"  {tag} = {value} (flags: {flags})")