Adds tests for Unix sockets

As per #3115, adds simple Unix socket connect/accept deadline tests in
pretty much the same way as the TCP connect/accept deadline tests work.

privval/socket_test.go

@@ -1,7 +1,9 @@
 package privval
 
 import (
+	"io/ioutil"
 	"net"
+	"os"
 	"testing"
 	"time"
 
@@ -82,3 +84,89 @@ func TestTCPListenerConnDeadline(t *testing.T) {
 	close(readyc)
 	<-donec
 }
+
+// testUnixAddr will attempt to obtain a platform-independent temporary file
+// name for a Unix socket
+func testUnixAddr() (string, error) {
+	f, err := ioutil.TempFile("", "tendermint-privval-test")
+	if err != nil {
+		return "", err
+	}
+	addr := f.Name()
+	f.Close()
+	os.Remove(addr)
+	return addr, nil
+}
+
+func TestUnixListenerAcceptDeadline(t *testing.T) {
+	addr, err := testUnixAddr()
+	if err != nil {
+		t.Fatal(err)
+	}
+	ln, err := net.Listen("unix", addr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	unixLn := NewUnixListener(ln)
+	UnixListenerAcceptDeadline(time.Millisecond)(unixLn)
+	UnixListenerConnDeadline(time.Second)(unixLn)
+
+	_, err = unixLn.Accept()
+	opErr, ok := err.(*net.OpError)
+	if !ok {
+		t.Fatalf("have %v, want *net.OpError", err)
+	}
+
+	if have, want := opErr.Op, "accept"; have != want {
+		t.Errorf("have %v, want %v", have, want)
+	}
+}
+
+func TestUnixListenerConnDeadline(t *testing.T) {
+	addr, err := testUnixAddr()
+	if err != nil {
+		t.Fatal(err)
+	}
+	ln, err := net.Listen("unix", addr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	unixLn := NewUnixListener(ln)
+	UnixListenerAcceptDeadline(time.Second)(unixLn)
+	UnixListenerConnDeadline(time.Millisecond)(unixLn)
+
+	readyc := make(chan struct{})
+	donec := make(chan struct{})
+	go func(ln net.Listener) {
+		defer close(donec)
+
+		c, err := ln.Accept()
+		if err != nil {
+			t.Fatal(err)
+		}
+		<-readyc
+
+		time.Sleep(2 * time.Millisecond)
+
+		msg := make([]byte, 200)
+		_, err = c.Read(msg)
+		opErr, ok := err.(*net.OpError)
+		if !ok {
+			t.Fatalf("have %v, want *net.OpError", err)
+		}
+
+		if have, want := opErr.Op, "read"; have != want {
+			t.Errorf("have %v, want %v", have, want)
+		}
+	}(unixLn)
+
+	dialer := DialUnixFn(addr)
+	_, err = dialer()
+	if err != nil {
+		t.Fatal(err)
+	}
+	close(readyc)
+	<-donec
+}