feat(fs): Export, test and document OnlyFilesFS (#3939)

fs_test.go

@@ -0,0 +1,71 @@
+package gin
+
+import (
+	"errors"
+	"net/http"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type mockFileSystem struct {
+	open func(name string) (http.File, error)
+}
+
+func (m *mockFileSystem) Open(name string) (http.File, error) {
+	return m.open(name)
+}
+
+func TestOnlyFilesFS_Open(t *testing.T) {
+	var testFile *os.File
+	mockFS := &mockFileSystem{
+		open: func(name string) (http.File, error) {
+			return testFile, nil
+		},
+	}
+	fs := &OnlyFilesFS{FileSystem: mockFS}
+
+	file, err := fs.Open("foo")
+
+	assert.NoError(t, err)
+	assert.Equal(t, testFile, file.(neutralizedReaddirFile).File)
+}
+
+func TestOnlyFilesFS_Open_err(t *testing.T) {
+	testError := errors.New("mock")
+	mockFS := &mockFileSystem{
+		open: func(_ string) (http.File, error) {
+			return nil, testError
+		},
+	}
+	fs := &OnlyFilesFS{FileSystem: mockFS}
+
+	file, err := fs.Open("foo")
+
+	assert.ErrorIs(t, err, testError)
+	assert.Nil(t, file)
+}
+
+func Test_neuteredReaddirFile_Readdir(t *testing.T) {
+	n := neutralizedReaddirFile{}
+
+	res, err := n.Readdir(0)
+
+	assert.NoError(t, err)
+	assert.Nil(t, res)
+}
+
+func TestDir_listDirectory(t *testing.T) {
+	testRoot := "foo"
+	fs := Dir(testRoot, true)
+
+	assert.Equal(t, http.Dir(testRoot), fs)
+}
+
+func TestDir(t *testing.T) {
+	testRoot := "foo"
+	fs := Dir(testRoot, false)
+
+	assert.Equal(t, &OnlyFilesFS{FileSystem: http.Dir(testRoot)}, fs)
+}