add config.Encode/Decode

config/config.go

@@ -3,7 +3,7 @@ package config
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -35,13 +35,13 @@ type Config struct {
 
 // ToFile writes a Config to a JSON file.
 func ToFile(path string, c Config) error {
-	sanitize(&c)
-	bytes, err := json.Marshal(c)
+	f, err := os.Create(path) // truncates existing file if it exists
 	if err != nil {
 		return err
 	}
+	defer f.Close()
 
-	err = ioutil.WriteFile(path, bytes, 0644)
+	err = Encode(f, c)
 	if err != nil {
 		return err
 	}
@@ -51,18 +51,30 @@ func ToFile(path string, c Config) error {
 
 // FromFile loads a Config object from a JSON file.
 func FromFile(path string) (c Config, err error) {
-	bytes, err := ioutil.ReadFile(path)
+	f, err := os.Open(path)
 	if err != nil {
-		return
+		return c, err
 	}
+	defer f.Close()
+	return Decode(f)
+}
+
+func Encode(w io.Writer, c Config) error {
+	sanitize(&c)
+	e := json.NewEncoder(w)
+	return e.Encode(c)
+}
 
-	err = json.Unmarshal(bytes, &c)
+func Decode(r io.Reader) (Config, error) {
+	d := json.NewDecoder(r)
+	var c Config
+	err := d.Decode(&c)
 	if err != nil {
-		return
+		return c, err
 	}
 	sanitize(&c)
 
-	return
+	return c, err
 }
 
 // HomeDir return's the user's canonical home directory.

config/config_test.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"bytes"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -34,41 +35,49 @@ func TestReadingWritingConfig(t *testing.T) {
 	filename := Filename(tmpDir)
 	assert.NoError(t, err)
 
-	currentConfig := Config{
-		GithubUsername:    "user",
-		APIKey:            "MyKey",
-		ExercismDirectory: "/exercism/directory",
-		Hostname:          "localhost\r\n",
-	}
-	sanitizedConfig := Config{
+	writtenConfig := Config{
 		GithubUsername:    "user",
 		APIKey:            "MyKey",
 		ExercismDirectory: "/exercism/directory",
 		Hostname:          "localhost",
 	}
 
-	ToFile(filename, currentConfig)
+	ToFile(filename, writtenConfig)
 
 	loadedConfig, err := FromFile(filename)
 	assert.NoError(t, err)
 
-	assert.Equal(t, sanitizedConfig, loadedConfig)
+	assert.Equal(t, writtenConfig, loadedConfig)
 }
 
-func TestSanitizeFields(t *testing.T) {
-	config := Config{
-		GithubUsername:    "user ",
-		APIKey:            "MyKey     ",
-		ExercismDirectory: "/home/user name\r\n",
-		Hostname:          "localhost\n",
-	}
+func TestDecodingConfig(t *testing.T) {
+	unsanitizedJson := `{"githubUsername":"user ","apiKey":"MyKey  ","exercismDirectory":"/exercism/directory\r\n","hostname":"localhost \r\n"}`
 	sanitizedConfig := Config{
 		GithubUsername:    "user",
 		APIKey:            "MyKey",
-		ExercismDirectory: "/home/user name",
+		ExercismDirectory: "/exercism/directory",
 		Hostname:          "localhost",
 	}
-	sanitize(&config)
+	b := bytes.NewBufferString(unsanitizedJson)
+	c, err := Decode(b)
 
-	assert.Equal(t, config, sanitizedConfig)
+	assert.NoError(t, err)
+	assert.Equal(t, sanitizedConfig, c)
+}
+
+func TestEncodingConfig(t *testing.T) {
+	currentConfig := Config{
+		GithubUsername:    "user\r\n",
+		APIKey:            "MyKey ",
+		ExercismDirectory: "/home/user name  ",
+		Hostname:          "localhost  ",
+	}
+	sanitizedJson := `{"githubUsername":"user","apiKey":"MyKey","exercismDirectory":"/home/user name","hostname":"localhost"}
+`
+
+	buf := new(bytes.Buffer)
+	err := Encode(buf, currentConfig)
+
+	assert.NoError(t, err)
+	assert.Equal(t, sanitizedJson, buf.String())
 }