getLine(): Always check for errors

Scan() can return true despite encountering an error. Encountered while
writing a test for the read timeout, also included.

goatherd.go

@@ -99,10 +99,9 @@ func errFatal(err error) {
 }
 
 func getLine(s *bufio.Scanner) (string, error) {
-	if !s.Scan() {
-		if err := s.Err(); err != nil {
-			return "", err
-		}
+	s.Scan()
+	if err := s.Err(); err != nil {
+		return "", err
 	}
 	line := s.Text()
 	if len(line) <= 0 {

goatherd_test.go

@@ -7,9 +7,11 @@ import (
 	"encoding/base64"
 	"fmt"
 	"io"
+	"net"
 	"os"
 	"sync"
 	"testing"
+	"time"
 
 	"github.com/gokyle/hotp"
 )
@@ -384,6 +386,23 @@ func handleConnT(t *testing.T) {
 	})
 }
 
+func listenT(t *testing.T) {
+	t.Run("timeout", func(t *testing.T) {
+		c, err := net.Dial("unix", "@goatherd_test")
+		tErrFatal(t, err)
+
+		t.Log("Waiting for timeout")
+		start := time.Now()
+		for {
+			if _, err = c.Write([]byte("a")); err != nil {
+				t.Logf("Write failed after %v with %q", time.Now().Sub(start), err)
+				break
+			}
+			time.Sleep(200 * time.Millisecond)
+		}
+	})
+}
+
 func TestMain(t *testing.T) {
 	if dbURL, ok := os.LookupEnv("DB_URL"); ok {
 		cfg.DbURL = dbURL
@@ -392,6 +411,7 @@ func TestMain(t *testing.T) {
 	}
 	cfg.Lookahead = 3
 	cfg.Debug = false
+	cfg.ReadTimeout.Duration = 1 * time.Second
 	faildelay.userlocks = make(map[string]*sync.Mutex)
 	stdinR, stdinW := io.Pipe()
 	stdinScanner, stdinWriter = bufio.NewScanner(stdinR), bufio.NewWriter(stdinW)
@@ -406,4 +426,12 @@ func TestMain(t *testing.T) {
 	t.Run("checkOffer", checkOfferT)
 	t.Run("incCount", incCountT)
 	t.Run("handleConn", handleConnT)
+
+	listener, err := net.Listen("unix", "@goatherd_test")
+	tErrFatal(t, err)
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go listen(&wg, listener)
+
+	t.Run("listen", listenT)
 }