cmd: fix JoinWithUserDir on Windows

Using the proper environment variable, and also filepath instead of
path.

Tested on Windows 8.

Fix #1169.

cmd/utils.go

@@ -9,16 +9,25 @@ import (
 	"errors"
 	"io/ioutil"
 	"os"
-	"path"
+	"path/filepath"
 	"strings"
 
 	"launchpad.net/gnuflag"
 )
 
+func getHome() string {
+	envs := []string{"HOME", "HOMEPATH"}
+	var home string
+	for i := 0; i < len(envs) && home == ""; i++ {
+		home = os.Getenv(envs[i])
+	}
+	return home
+}
+
 func JoinWithUserDir(p ...string) string {
-	paths := []string{os.ExpandEnv("$HOME")}
+	paths := []string{getHome()}
 	paths = append(paths, p...)
-	return path.Join(paths...)
+	return filepath.Join(paths...)
 }
 
 func writeToken(token string) error {

cmd/utils_test.go

@@ -6,12 +6,28 @@ package cmd
 
 import (
 	"io/ioutil"
+	"os"
+	"path"
 
 	"github.com/tsuru/tsuru/fs/fstest"
 	"gopkg.in/check.v1"
 	"launchpad.net/gnuflag"
 )
 
+func (s *S) TestJoinWithUserDir(c *check.C) {
+	expected := path.Join(os.Getenv("HOME"), "a", "b")
+	path := JoinWithUserDir("a", "b")
+	c.Assert(path, check.Equals, expected)
+}
+
+func (s *S) TestJoinWithUserDirHomePath(c *check.C) {
+	defer os.Setenv("HOME", os.Getenv("HOME"))
+	os.Setenv("HOME", "")
+	os.Setenv("HOMEPATH", "/wat")
+	path := JoinWithUserDir("a", "b")
+	c.Assert(path, check.Equals, "/wat/a/b")
+}
+
 func (s *S) TestWriteToken(c *check.C) {
 	rfs := &fstest.RecordingFs{}
 	fsystem = rfs