Improve test assertion for Linux

diff --git a/reuse_test.go b/reuse_test.go
index ba53f288766e39cd687ce73fc2b1244557ab203c..5da4ab8096b922ab6c8a2e1735ee7a87ab2d7a79 100644 (file)
--- a/reuse_test.go
+++ b/reuse_test.go
@@ -2,7 +2,6 @@ package torrent
 
 import (
        "context"
-       "errors"
        "net"
        "sync/atomic"
        "syscall"
@@ -19,17 +18,25 @@ func TestTcpPortReuseIsABadIdea(t *testing.T) {
        c.Assert(err, qt.IsNil)
        defer remote.Close()
        dialer := net.Dialer{}
+       // Show that we can't duplicate an existing connection even with various socket options.
        dialer.Control = func(network, address string, c syscall.RawConn) (err error) {
                return c.Control(func(fd uintptr) {
                        err = setReusePortSockOpts(fd)
                })
        }
+       // Tie up a local port to the remote.
        first, err := dialer.Dial("tcp", remote.Addr().String())
        c.Assert(err, qt.IsNil)
        defer first.Close()
+       // Show that dialling the remote with the same local port fails.
        dialer.LocalAddr = first.LocalAddr()
        _, err = dialer.Dial("tcp", remote.Addr().String())
-       c.Assert(errors.Is(err, syscall.EADDRINUSE), qt.IsTrue)
+       c.Assert(err, qt.IsNotNil)
+       // Show that not fixing the local port again allows connections to succeed.
+       dialer.LocalAddr = nil
+       second, err := dialer.Dial("tcp", remote.Addr().String())
+       c.Assert(err, qt.IsNil)
+       second.Close()
 }
 
 // Show that multiple connections from the same local utp socket to the same remote port will