Switch order in box.find to lookup for directories (#87)

* Fix order for checking directories in box.find

* Add godoc comments

* Add test cases & subfolder-file

box.go

@@ -15,6 +15,7 @@ import (
 )
 
 var (
+	// ErrResOutsideBox gets returned in case of the requested resources being outside the box
 	ErrResOutsideBox = errors.New("Can't find a resource outside the box")
 )
 
@@ -51,10 +52,12 @@ type Box struct {
 	directories map[string]bool
 }
 
+// AddString converts t to a byteslice and delegates to AddBytes to add to b.data
 func (b Box) AddString(path string, t string) {
 	b.AddBytes(path, []byte(t))
 }
 
+// AddBytes sets t in b.data by the given path
 func (b Box) AddBytes(path string, t []byte) {
 	b.data[path] = t
 }
@@ -132,14 +135,14 @@ func (b Box) find(name string) (File, error) {
 			bb = b.decompress(bb)
 			return newVirtualFile(cleanName, bb), nil
 		}
+		if _, ok := b.directories[cleanName]; ok {
+			return newVirtualDir(cleanName), nil
+		}
 		if filepath.Ext(cleanName) != "" {
 			// The Handler created by http.FileSystem checks for those errors and
 			// returns http.StatusNotFound instead of http.StatusInternalServerError.
 			return nil, os.ErrNotExist
 		}
-		if _, ok := b.directories[cleanName]; ok {
-			return newVirtualDir(cleanName), nil
-		}
 		return nil, os.ErrNotExist
 	}
 

box_test.go

@@ -77,6 +77,10 @@ func Test_Box_find(t *testing.T) {
 		{"assets/app.css", true},
 		{"assets\\app.css", onWindows},
 		{"foo/bar.baz", false},
+		{"bar", true},
+		{"bar/sub", true},
+		{"bar/foo", false},
+		{"bar/sub/sub.html", true},
 	}
 
 	for _, tt := range table {