Raise a better exception when peer sends no certificates on Windows (#…

…135)

Co-authored-by: David Glick <[email protected]>

src/truststore/_windows.py

@@ -325,6 +325,12 @@ def _verify_peercerts_impl(
     server_hostname: str | None = None,
 ) -> None:
     """Verify the cert_chain from the server using Windows APIs."""
+
+    # If the peer didn't send any certificates then
+    # we can't do verification. Raise an error.
+    if not cert_chain:
+        raise ssl.SSLCertVerificationError("Peer sent no certificates to verify")
+
     pCertContext = None
     hIntermediateCertStore = CertOpenStore(CERT_STORE_PROV_MEMORY, 0, None, 0, None)
     try: