net: make TestInterfaceList work on non-English Windows

Fixes #13198

The output of netsh is encoded with ANSI encoding. So doesn't match with UTF-8 strings.
Write output as UTF-8 using powershell.

Change-Id: I6c7e93c590ed407f24ae847601d71df9523e028c
Reviewed-on: https://go-review.googlesource.com/16756
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

diff --git a/src/net/net_windows_test.go b/src/net/net_windows_test.go
index 4f6bd45929b8e480629dbfb2d707ba16cb49b453..ba81ebbb359ec0ed4c042ec4d5ce4bb7b4f52238 100644 (file)
--- a/src/net/net_windows_test.go
+++ b/src/net/net_windows_test.go
@@ -9,6 +9,7 @@ import (
        "bytes"
        "fmt"
        "io"
+       "io/ioutil"
        "os"
        "os/exec"
        "sort"
@@ -177,10 +178,39 @@ func isWindowsXP(t *testing.T) bool {
 }
 
 func listInterfacesWithNetsh() ([]string, error) {
-       out, err := exec.Command("netsh", "interface", "ip", "show", "config").CombinedOutput()
+       removeUTF8BOM := func(b []byte) []byte {
+               if len(b) >= 3 && b[0] == 0xEF && b[1] == 0xBB && b[2] == 0xBF {
+                       return b[3:]
+               }
+               return b
+       }
+       f, err := ioutil.TempFile("", "netsh")
+       if err != nil {
+               return nil, err
+       }
+       f.Close()
+       defer os.Remove(f.Name())
+       cmd := fmt.Sprintf(`netsh interface ip show config | Out-File "%s" -encoding UTF8`, f.Name())
+       out, err := exec.Command("powershell", "-Command", cmd).CombinedOutput()
+       if err != nil {
+               if len(out) != 0 {
+                       return nil, fmt.Errorf("netsh failed: %v: %q", err, string(removeUTF8BOM(out)))
+               }
+               var err2 error
+               out, err2 = ioutil.ReadFile(f.Name())
+               if err2 != nil {
+                       return nil, err2
+               }
+               if len(out) != 0 {
+                       return nil, fmt.Errorf("netsh failed: %v: %q", err, string(removeUTF8BOM(out)))
+               }
+               return nil, fmt.Errorf("netsh failed: %v", err)
+       }
+       out, err = ioutil.ReadFile(f.Name())
        if err != nil {
-               return nil, fmt.Errorf("netsh failed: %v: %q", err, string(out))
+               return nil, err
        }
+       out = removeUTF8BOM(out)
        lines := bytes.Split(out, []byte{'\r', '\n'})
        names := make([]string, 0)
        for _, line := range lines {