Added functionality to mock the environment variable store, for tests

util.go

@@ -94,16 +94,16 @@ func insensitiviseMap(m map[string]interface{}) {
 	}
 }
 
-func absPathify(inPath string) string {
+func absPathify(inPath string, envStore EnvStore) string {
 	jww.INFO.Println("Trying to resolve absolute path to", inPath)
 
 	if strings.HasPrefix(inPath, "$HOME") {
-		inPath = userHomeDir() + inPath[5:]
+		inPath = userHomeDir(envStore) + inPath[5:]
 	}
 
 	if strings.HasPrefix(inPath, "$") {
 		end := strings.Index(inPath, string(os.PathSeparator))
-		inPath = os.Getenv(inPath[1:end]) + inPath[end:]
+		inPath = envStore.Get(inPath[1:end]) + inPath[end:]
 	}
 
 	if filepath.IsAbs(inPath) {
@@ -141,15 +141,15 @@ func stringInSlice(a string, list []string) bool {
 	return false
 }
 
-func userHomeDir() string {
+func userHomeDir(store EnvStore) string {
 	if runtime.GOOS == "windows" {
-		home := os.Getenv("HOMEDRIVE") + os.Getenv("HOMEPATH")
+		home := store.Get("HOMEDRIVE") + store.Get("HOMEPATH")
 		if home == "" {
-			home = os.Getenv("USERPROFILE")
+			home = store.Get("USERPROFILE")
 		}
 		return home
 	}
-	return os.Getenv("HOME")
+	return store.Get("HOME")
 }
 
 func unmarshallConfigReader(in io.Reader, c map[string]interface{}, configType string) error {

viper.go

@@ -96,6 +96,16 @@ func (fnfe ConfigFileNotFoundError) Error() string {
 	return fmt.Sprintf("Config File %q Not Found in %q", fnfe.name, fnfe.locations)
 }
 
+type EnvStore interface {
+	Get(key string) string
+}
+
+type RealEnvStore struct {}
+
+func (e *RealEnvStore) Get(key string) string {
+	return os.Getenv(key)
+}
+
 // Viper is a prioritized configuration registry. It
 // maintains a set of configuration sources, fetches
 // values to populate those, and provides them according
@@ -163,10 +173,11 @@ type Viper struct {
 	typeByDefValue bool
 
 	onConfigChange func(fsnotify.Event)
+
+	envStore       EnvStore
 }
 
-// New returns an initialized Viper instance.
-func New() *Viper {
+func baseNew() *Viper {
 	v := new(Viper)
 	v.keyDelim = "."
 	v.configName = "config"
@@ -179,10 +190,27 @@ func New() *Viper {
 	v.env = make(map[string]string)
 	v.aliases = make(map[string]string)
 	v.typeByDefValue = false
+	v.envStore = new(RealEnvStore)
 
 	return v
 }
 
+// New returns an initialized Viper instance.
+func New() *Viper {
+	v := baseNew()
+	v.fs = afero.NewOsFs()
+	v.envStore = new(RealEnvStore)
+
+	return v
+}
+
+func newFrom(from *Viper) *Viper {
+	v := baseNew()
+	v.fs = from.fs
+	v.envStore = from.envStore
+	return v
+}
+
 // Intended for testing, will reset all to default settings.
 // In the public interface for the viper package so applications
 // can use it in their testing as well.
@@ -313,14 +341,14 @@ func (v *Viper) mergeWithEnvPrefix(in string) string {
 // rewriting keys many things, Ex: Get('someKey') -> some_key
 // (camel case to snake case for JSON keys perhaps)
 
-// getEnv is a wrapper around os.Getenv which replaces characters in the original
+// getEnv is a wrapper around EnvStore.Get which replaces characters in the original
 // key. This allows env vars which have different keys than the config object
 // keys.
 func (v *Viper) getEnv(key string) string {
 	if v.envKeyReplacer != nil {
 		key = v.envKeyReplacer.Replace(key)
 	}
-	return os.Getenv(key)
+	return v.envStore.Get(key)
 }
 
 // ConfigFileUsed returns the file used to populate the config registry.
@@ -332,7 +360,7 @@ func (v *Viper) ConfigFileUsed() string { return v.configFile }
 func AddConfigPath(in string) { v.AddConfigPath(in) }
 func (v *Viper) AddConfigPath(in string) {
 	if in != "" {
-		absin := absPathify(in)
+		absin := absPathify(in, v.envStore)
 		jww.INFO.Println("adding", absin, "to paths to search")
 		if !stringInSlice(absin, v.configPaths) {
 			v.configPaths = append(v.configPaths, absin)
@@ -630,7 +658,7 @@ func (v *Viper) Get(key string) interface{} {
 // Sub is case-insensitive for a key.
 func Sub(key string) *Viper { return v.Sub(key) }
 func (v *Viper) Sub(key string) *Viper {
-	subv := New()
+	subv := newFrom(v)
 	data := v.Get(key)
 	if data == nil {
 		return nil
@@ -1480,6 +1508,11 @@ func (v *Viper) SetFs(fs afero.Fs) {
 	v.fs = fs
 }
 
+func SetEnvStore(store EnvStore) { v.SetEnvStore(store) }
+func (v *Viper) SetEnvStore(store EnvStore) {
+	v.envStore = store
+}
+
 // SetConfigName sets name for the config file.
 // Does not include extension.
 func SetConfigName(in string) { v.SetConfigName(in) }

viper_test.go

@@ -360,6 +360,50 @@ func TestRemotePrecedence(t *testing.T) {
 	Set("newkey", "remote")
 }
 
+type mapEnv struct {
+	m map[string]string
+}
+
+func (e *mapEnv) Get(key string) string {
+	if val, ok := e.m[key]; ok {
+		return val
+	} else {
+		return ""
+	}
+}
+
+func (e *mapEnv) Set(key, value string) {
+	e.m[key] = value
+}
+
+func newMapEnv() *mapEnv {
+	mapEnv := new(mapEnv)
+	mapEnv.m = make(map[string]string)
+	return mapEnv
+}
+
+func TestMockEnv(t *testing.T) {
+	e := newMapEnv()
+
+	initJSON()
+	v.SetEnvStore(e)
+
+	BindEnv("id")
+	BindEnv("f", "FOOD")
+
+	e.Set("ID", "13")
+	e.Set("FOOD", "apple")
+	e.Set("NAME", "crunk")
+
+	assert.Equal(t, "13", Get("id"))
+	assert.Equal(t, "apple", Get("f"))
+	assert.Equal(t, "Cake", Get("name"))
+
+	AutomaticEnv()
+
+	assert.Equal(t, "crunk", Get("name"))
+}
+
 func TestEnv(t *testing.T) {
 	initJSON()