Make repository response support HTTP range request (#24592)

Replace #20480
Replace #18448

Close #16414

modules/httplib/mock.go

@@ -0,0 +1,35 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package httplib
+
+import (
+	"bytes"
+	"net/http"
+)
+
+type MockResponseWriter struct {
+	header http.Header
+
+	StatusCode int
+	BodyBuffer bytes.Buffer
+}
+
+func (m *MockResponseWriter) Header() http.Header {
+	return m.header
+}
+
+func (m *MockResponseWriter) Write(bytes []byte) (int, error) {
+	if m.StatusCode == 0 {
+		m.StatusCode = http.StatusOK
+	}
+	return m.BodyBuffer.Write(bytes)
+}
+
+func (m *MockResponseWriter) WriteHeader(statusCode int) {
+	m.StatusCode = statusCode
+}
+
+func NewMockResponseWriter() *MockResponseWriter {
+	return &MockResponseWriter{header: http.Header{}}
+}