vlib: fix tcp_test.v

The listen_tcp method should not accept .unix af.
Test that it indeed fails when invoked.

vlib/net/tcp_test.v

@@ -1,20 +1,17 @@
-// vtest flaky: true
-// vtest retry: 8
 import net
-import os
 
 const test_port = 45123
 
-fn handle_conn(mut c net.TcpConn) {
+fn handle_conn(mut c net.TcpConn) ! {
  for {
  mut buf := []u8{len: 100, init: 0}
  read := c.read(mut buf) or {
- println('Server: connection dropped')
- return
+ eprintln('Server: connection dropped')
+ return err
  }
  c.write(buf[..read]) or {
- println('Server: connection dropped')
- return
+ eprintln('Server: connection dropped')
+ return err
  }
  }
 }
@@ -24,40 +21,35 @@ fn one_shot_echo_server(mut l net.TcpListener, ch_started chan int) ! {
  ch_started <- 1
  mut new_conn := l.accept() or { return error('could not accept') }
  eprintln(' > new_conn: ${new_conn}')
- handle_conn(mut new_conn)
- new_conn.close() or {}
+ handle_conn(mut new_conn)!
+ new_conn.close()!
 }
 
 fn echo(address string) ! {
  mut c := net.dial_tcp(address)!
- defer {
- c.close() or {}
- }
 
- println('local: ' + c.addr()!.str())
- println(' peer: ' + c.peer_addr()!.str())
+ eprintln('local: ' + c.addr()!.str())
+ eprintln(' peer: ' + c.peer_addr()!.str())
 
  data := 'Hello from vlib/net!'
  c.write_string(data)!
  mut buf := []u8{len: 4096}
- read := c.read(mut buf) or { panic(err) }
+ read := c.read(mut buf)!
  assert read == data.len
  for i := 0; i < read; i++ {
  assert buf[i] == data[i]
  }
- println('Got "${buf.bytestr()}"')
+ c.close()!
 }
 
 fn test_tcp_ip6() {
  eprintln('\n>>> ${@FN}')
- address := 'localhost:${test_port}'
- mut l := net.listen_tcp(.ip6, ':${test_port}') or { panic(err) }
+ address := '::1:${test_port}'
+ mut l := net.listen_tcp(.ip6, address) or { panic(err) }
  dump(l)
  start_echo_server(mut l)
  echo(address) or { panic(err) }
- l.close() or {}
- // ensure there is at least one new socket created before the next test
- l = net.listen_tcp(.ip6, ':${test_port + 1}') or { panic(err) }
+ l.close() or { panic(err) }
 }
 
 fn start_echo_server(mut l net.TcpListener) {
@@ -68,31 +60,21 @@ fn start_echo_server(mut l net.TcpListener) {
 
 fn test_tcp_ip() {
  eprintln('\n>>> ${@FN}')
- address := 'localhost:${test_port}'
+ address := '127.0.0.1:${test_port}'
  mut l := net.listen_tcp(.ip, address) or { panic(err) }
  dump(l)
  start_echo_server(mut l)
  echo(address) or { panic(err) }
- l.close() or {}
+ l.close() or { panic(err) }
 }
 
 fn test_tcp_unix() {
  eprintln('\n>>> ${@FN}')
- // TODO(emily):
- // whilst windows supposedly supports unix sockets
- // this doesnt work (wsaeopnotsupp at the call to bind())
- $if !windows {
- address := os.real_path('tcp-test.sock')
- // address := 'tcp-test.sock'
- println('${address}')
-
- mut l := net.listen_tcp(.unix, address) or { panic(err) }
- start_echo_server(mut l)
- echo(address) or { panic(err) }
- l.close() or {}
+ address := 'tcp-test.sock'
+ eprintln('${address}')
 
-  os.rm(address) or { panic('failed to remove socket file') }
- }
+ mut l := net.listen_tcp(.unix, address) or { return }
+ assert false
 }
 
 fn testsuite_end() {
@@ -103,6 +85,6 @@ fn test_bind() {
  $if !network ? {
  return
  }
- mut conn := net.dial_tcp_with_bind('vlang.io:80', '127.0.0.1:0')!
- conn.close()!
+ mut conn := net.dial_tcp_with_bind('vlang.io:80', '127.0.0.1:0') or { panic(err) }
+ conn.close() or { panic(err) }
 }