Ensure ConnStats spew nicely

conn_stats.go

@@ -1,6 +1,7 @@
 package torrent
 
 import (
+	"fmt"
 	"io"
 	"reflect"
 	"sync/atomic"
@@ -48,6 +49,8 @@ type Count struct {
 	n int64
 }
 
+var _ fmt.Stringer = (*Count)(nil)
+
 func (me *Count) Add(n int64) {
 	atomic.AddInt64(&me.n, n)
 }
@@ -56,6 +59,10 @@ func (me *Count) Int64() int64 {
 	return atomic.LoadInt64(&me.n)
 }
 
+func (me *Count) String() string {
+	return fmt.Sprintf("%v", me.Int64())
+}
+
 func (cs *ConnStats) wroteMsg(msg *pp.Message) {
 	// TODO: Track messages and not just chunks.
 	switch msg.Type {

misc_test.go

@@ -1,10 +1,13 @@
 package torrent
 
 import (
+	"reflect"
+	"strings"
 	"testing"
 
 	"github.com/anacrolix/missinggo/bitmap"
 	"github.com/anacrolix/missinggo/iter"
+	"github.com/davecgh/go-spew/spew"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -29,3 +32,10 @@ func TestIterBitmapsDistinct(t *testing.T) {
 	assert.Equal(t, []interface{}{0, 3, 2}, iter.ToSlice(iterBitmapsDistinct(&skipCopy, first, second)))
 	assert.Equal(t, []int{1}, skip.ToSortedSlice())
 }
+
+func TestSpewConnStats(t *testing.T) {
+	s := spew.Sdump(ConnStats{})
+	t.Logf("\n%s\n", s)
+	lines := strings.Count(s, "\n")
+	assert.EqualValues(t, 2+reflect.ValueOf(ConnStats{}).NumField(), lines)
+}