From a0fe3404bf91136124e8416ddabd03998a89e826 Mon Sep 17 00:00:00 2001
From: Victor Gaydov <victor@enise.org>
Date: Tue, 12 Jul 2016 10:42:39 +0400
Subject: [PATCH] Add test for fsSmallFileReader.WriteTo and fix bug (#128)

The bug raises when io.Writer passed to fsSmallFileReader.WriteTo
doesn't support ReadFrom interface.
---
 fs.go      |  2 +-
 fs_test.go | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/fs.go b/fs.go
index 4ea097a..c36073d 100644
--- a/fs.go
+++ b/fs.go
@@ -593,7 +593,7 @@ func (r *fsSmallFileReader) WriteTo(w io.Writer) (int64, error) {
 	curPos := r.startPos
 	bufv := copyBufPool.Get()
 	buf := bufv.([]byte)
-	for err != nil {
+	for err == nil {
 		tailLen := r.endPos - curPos
 		if tailLen <= 0 {
 			break
diff --git a/fs_test.go b/fs_test.go
index d502f1a..9eda008 100644
--- a/fs_test.go
+++ b/fs_test.go
@@ -4,9 +4,11 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"math/rand"
 	"os"
+	"path"
 	"sort"
 	"testing"
 	"time"
@@ -88,6 +90,57 @@ func TestServeFileHead(t *testing.T) {
 	}
 }
 
+func TestServeFileSmallNoReadFrom(t *testing.T) {
+	teststr := "hello, world!"
+
+	tempdir, err := ioutil.TempDir("", "httpexpect")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tempdir)
+
+	if err := ioutil.WriteFile(
+		path.Join(tempdir, "hello"), []byte(teststr), 0666); err != nil {
+		t.Fatal(err)
+	}
+
+	var ctx RequestCtx
+	var req Request
+	req.SetRequestURI("http://foobar.com/baz")
+	ctx.Init(&req, nil, nil)
+
+	ServeFile(&ctx, path.Join(tempdir, "hello"))
+
+	reader, ok := ctx.Response.bodyStream.(*fsSmallFileReader)
+	if !ok {
+		t.Fatal("expected fsSmallFileReader")
+	}
+
+	buf := bytes.NewBuffer(nil)
+
+	n, err := reader.WriteTo(pureWriter{buf})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if n != int64(len(teststr)) {
+		t.Fatalf("expected %d bytes, got %d bytes", len(teststr), n)
+	}
+
+	body := string(buf.Bytes())
+	if body != teststr {
+		t.Fatalf("expected '%s'", teststr)
+	}
+}
+
+type pureWriter struct {
+	w io.Writer
+}
+
+func (pw pureWriter) Write(p []byte) (nn int, err error) {
+	return pw.w.Write(p)
+}
+
 func TestServeFileCompressed(t *testing.T) {
 	var ctx RequestCtx
 	var req Request