Use platform independent pathnames

config/config.go

@@ -96,7 +96,7 @@ func (c *Config) Read(file string) error {
 		if err != nil {
 			return err
 		}
-		file = fmt.Sprintf("%s/%s", home, File)
+		file = filepath.Join(home, File)
 	}
 
 	if _, err := os.Stat(file); err != nil {
@@ -176,7 +176,7 @@ func (c *Config) configure() (*Config, error) {
 	if err != nil {
 		return c, err
 	}
-	c.file = fmt.Sprintf("%s/%s", dir, File)
+	c.file = filepath.Join(dir, File)
 
 	// use legacy value, if it exists
 	if c.ExercismDirectory != "" {
@@ -185,7 +185,7 @@ func (c *Config) configure() (*Config, error) {
 
 	// fall back to default value
 	if c.Dir == "" {
-		c.Dir = fmt.Sprintf("%s/%s", dir, DirExercises)
+		c.Dir = filepath.Join(dir, DirExercises)
 	}
 	c.Dir = strings.Replace(c.Dir, "~/", fmt.Sprintf("%s/", dir), 1)
 	return c, nil
@@ -201,7 +201,7 @@ func FilePath(file string) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	return fmt.Sprintf("%s/%s", dir, File), nil
+	return filepath.Join(dir, File), nil
 }
 
 // IsAuthenticated returns true if the config contains an API key.

handlers/item.go

@@ -1,7 +1,6 @@
 package handlers
 
 import (
-	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -17,7 +16,7 @@ type Item struct {
 }
 
 func (it *Item) Path() string {
-	return fmt.Sprintf("%s/%s", it.dir, it.Problem.ID)
+	return filepath.Join(it.dir, it.TrackID, it.Slug)
 }
 
 func (it *Item) Matches(filter HWFilter) bool {
@@ -39,7 +38,7 @@ func (it *Item) Save() error {
 	}
 
 	for name, text := range it.Files {
-		file := fmt.Sprintf("%s/%s/%s", it.dir, it.ID, name)
+		file := filepath.Join(it.Path(), name)
 
 		err := os.MkdirAll(filepath.Dir(file), 0755)
 		if err != nil {

handlers/logout_test.go

@@ -2,9 +2,9 @@ package handlers
 
 import (
 	"flag"
-	"fmt"
 	"io/ioutil"
 	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/codegangsta/cli"
@@ -16,7 +16,7 @@ func TestLogoutDeletesConfigFile(t *testing.T) {
 	tmpDir, err := ioutil.TempDir("", "")
 	assert.NoError(t, err)
 
-	file := fmt.Sprintf("%s/%s", tmpDir, config.File)
+	file := filepath.Join(tmpDir, config.File)
 
 	c := config.Config{}
 	c.SavePath(file)