set ::done HAND
        catch {tls::handshake $sock} msg
        set ::done $msg
    } 
    # NOTE: when doing an in-process client/server test, both sides need
    # to be non-blocking for the TLS handshake

    # Server - Only accept TLS 1 or higher
    set s [tls::socket \
               -certfile $serverCert -cafile $caCert -keyfile $serverKey \
               -request 0 -require 0 -ssl2 0 -ssl3 0 -tls1 1 -tls1.1 1 -tls1.2 1 \
               -server Accept 8831]
    # Client - Only propose SSL3
    set c [tls::socket -async \
               -cafile $caCert \
               -request 0 -require 0 -ssl2 0 -ssl3 1 -tls1 0 -tls1.1 0 -tls1.2 0 \
               [info hostname] 8831]
    fconfigure $c -blocking 0
    puts $c a ; flush $c
    after 5000 [list set ::done timeout]
    vwait ::done
    set ::done
} {handshake failed: wrong version number}