Do not allow empty paths

This reverts commit b9848a5.

Author: cmaglie

paths.go

@@ -48,7 +48,10 @@ type Path struct {
 // then nil is returned.
 func New(path ...string) *Path {
 	if len(path) == 0 {
-		return New("")
+		return nil
+	}
+	if len(path) == 1 && path[0] == "" {
+		return nil
 	}
 	res := &Path{path: path[0]}
 	if len(path) > 1 {

paths_test.go

@@ -44,10 +44,10 @@ func TestPathNew(t *testing.T) {
 	require.Equal(t, filepath.Join("path", "path"), test2.String())
 
 	test3 := New()
-	require.Equal(t, "", test3.String())
+	require.Nil(t, test3)
 
 	test4 := New("")
-	require.Equal(t, "", test4.String())
+	require.Nil(t, test4)
 }
 
 func TestPath(t *testing.T) {