py-cert-test.py

import os
import ssl
import urllib.request

openssl_dir, openssl_cafile = os.path.split(
    ssl.get_default_verify_paths().openssl_cafile)
# no content in this folder
os.listdir(openssl_dir)
# non existent file
ssl_file = os.path.join(openssl_dir, openssl_cafile)
cert_exists = os.path.exists(ssl_file)
print(f"File {ssl_file} exists? {cert_exists}.")

urls = [
    'https://sha256.badssl.com/', # should succeed
    'https://arenaxr.org/conf/gauth.json', # should succeed
    'https://untrusted-root.badssl.com/', # should fail
]
for url in urls:
    print(f"Testing {url}...")
    try:
        with urllib.request.urlopen(url) as response:
            html = response.read()
    except os.error as err:
        print(f"URL failed. {err=}, {type(err)=}")