fix: make tests robust for go 1.13

The file descriptors aren't stable unless we re-exec this way.

sockets_test.go

@@ -3,86 +3,97 @@
 package sockets
 
 import (
+	"fmt"
 	"io/ioutil"
 	"net"
 	"os"
+	"os/exec"
 	"strconv"
 	"testing"
 )
 
 func TestActivation(t *testing.T) {
-	lt, err := net.ListenTCP("tcp", &net.TCPAddr{IP: net.IPv6loopback})
-	if err != nil {
-		t.Fatal(err)
-	}
-	if c, err := lt.SyscallConn(); err == nil {
-		var fd uintptr
-		c.Control(func(nfd uintptr) {
-			fd = nfd
-		})
-		if fd != 3 {
-			t.Fatal("expected fd to be 3")
+	testTcpAddr := os.Getenv("SOCKET_TEST_TCP_ADDR")
+	testUdpAddr := os.Getenv("SOCKET_TEST_UDP_ADDR")
+	if testTcpAddr == "" {
+		lt, err := net.ListenTCP("tcp", &net.TCPAddr{IP: net.IPv6loopback})
+		if err != nil {
+			t.Fatal(err)
+		}
+		tcpAddr := lt.Addr()
+		ltf, err := lt.File()
+		lt.Close()
+		if err != nil {
+			t.Fatal(err)
 		}
-	} else {
-		t.Fatal(err)
-	}
 
-	lu, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.IPv6loopback})
-	if err != nil {
-		t.Fatal(err)
-	}
-	if c, err := lu.SyscallConn(); err == nil {
-		var fd uintptr
-		c.Control(func(nfd uintptr) {
-			fd = nfd
-		})
-		if fd != 4 {
-			t.Fatal("expected fd to be 3")
+		lu, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.IPv6loopback})
+		if err != nil {
+			t.Fatal(err)
+		}
+		udpAddr := lu.LocalAddr()
+		luf, err := lu.File()
+		lu.Close()
+		if err != nil {
+			t.Fatal(err)
 		}
-	} else {
-		t.Fatal(err)
-	}
 
-	os.Setenv("LISTEN_FDS", "2")
-	os.Setenv("LISTEN_PID", strconv.Itoa(os.Getpid()))
-	os.Setenv("LISTEN_FDNAMES", "tcp:udp")
-	tcp, err := TakeListeners("tcp")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if len(tcp) != 1 {
-		t.Fatalf("expected 1 listener, got %d", len(tcp))
-	}
+		cmd := exec.Command("/proc/self/exe", "-test.run", "TestActivation")
+		cmd.ExtraFiles = append(cmd.ExtraFiles, ltf, luf)
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+		cmd.Env = append(
+			cmd.Env,
+			"LISTEN_FDS=2",
+			"LISTEN_FDNAMES=tcp:udp",
+			fmt.Sprintf("SOCKET_TEST_TCP_ADDR=%s", tcpAddr),
+			fmt.Sprintf("SOCKET_TEST_UDP_ADDR=%s", udpAddr),
+		)
+		err = cmd.Run()
+		if err != nil {
+			t.Fatal(err)
+		}
+	} else {
+		// can't set this from the parent because we can't run anything between fork/exec.
+		os.Setenv("LISTEN_PID", strconv.Itoa(os.Getpid()))
+		tcp, err := TakeListeners("tcp")
+		if err != nil {
+			t.Fatal(err)
+		}
+		if len(tcp) != 1 {
+			t.Fatalf("expected 1 listener, got %d", len(tcp))
+		}
 
-	go func() {
-		l := tcp[0]
-		c, err := l.Accept()
+		go func() {
+			l := tcp[0]
+			c, err := l.Accept()
+			if err != nil {
+				t.Error(err)
+				return
+			}
+			c.Write([]byte("foobar"))
+			c.Close()
+		}()
+		c, err := net.Dial("tcp6", testTcpAddr)
+		if err != nil {
+			t.Fatal(err)
+		}
+		b, err := ioutil.ReadAll(c)
 		if err != nil {
 			t.Error(err)
-			return
 		}
-		c.Write([]byte("foobar"))
-		c.Close()
-	}()
-	c, err := net.DialTCP("tcp", nil, lt.Addr().(*net.TCPAddr))
-	if err != nil {
-		t.Fatal(err)
-	}
-	b, err := ioutil.ReadAll(c)
-	if err != nil {
-		t.Error(err)
-	}
-	if string(b) != "foobar" {
-		t.Error("wrong message")
-	}
-	udp, err := TakePacketConns("udp")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if len(udp) != 1 {
-		t.Fatalf("expected 1 listener, got %d", len(tcp))
-	}
-	if udp[0].LocalAddr().String() != lu.LocalAddr().String() {
-		t.Fatal("got the wrong udp listener")
+		if string(b) != "foobar" {
+			t.Error("wrong message")
+		}
+		udp, err := TakePacketConns("udp")
+		if err != nil {
+			t.Fatal(err)
+		}
+		if len(udp) != 1 {
+			t.Fatalf("expected 1 listener, got %d", len(tcp))
+		}
+		if udp[0].LocalAddr().String() != testUdpAddr {
+			t.Fatal("got the wrong udp listener")
+		}
 	}
 }