Add benchmark tests and related configurations for performance evaluation

test/test_benchmark.cc

@@ -0,0 +1,78 @@
+#include <httplib.h>
+
+#include <gtest/gtest.h>
+
+#include <algorithm>
+#include <chrono>
+#include <sstream>
+#include <thread>
+#include <vector>
+
+using namespace httplib;
+
+static const int PORT = 11134;
+
+static void performance_test(const char *host) {
+  Server svr;
+
+  svr.Get("/benchmark", [&](const Request & /*req*/, Response &res) {
+    res.set_content("Benchmark Response", "text/plain");
+  });
+
+  auto listen_thread = std::thread([&]() { svr.listen(host, PORT); });
+  auto se = detail::scope_exit([&] {
+    svr.stop();
+    listen_thread.join();
+    ASSERT_FALSE(svr.is_running());
+  });
+
+  svr.wait_until_ready();
+
+  Client cli(host, PORT);
+
+  // Warm-up request to establish connection and resolve DNS
+  auto warmup_res = cli.Get("/benchmark");
+  ASSERT_TRUE(warmup_res); // Ensure server is responding correctly
+
+  // Run multiple trials and collect timings
+  const int num_trials = 20;
+  std::vector<int64_t> timings;
+  timings.reserve(num_trials);
+
+  for (int i = 0; i < num_trials; i++) {
+    auto start = std::chrono::high_resolution_clock::now();
+    auto res = cli.Get("/benchmark");
+    auto end = std::chrono::high_resolution_clock::now();
+
+    auto elapsed =
+        std::chrono::duration_cast<std::chrono::milliseconds>(end - start)
+            .count();
+
+    // Assertions after timing measurement to avoid overhead
+    ASSERT_TRUE(res);
+    EXPECT_EQ(StatusCode::OK_200, res->status);
+
+    timings.push_back(elapsed);
+  }
+
+  // Calculate 25th percentile (lower quartile)
+  std::sort(timings.begin(), timings.end());
+  auto p25 = timings[num_trials / 4];
+
+  // Format timings for output
+  std::ostringstream timings_str;
+  timings_str << "[";
+  for (size_t i = 0; i < timings.size(); i++) {
+    if (i > 0) timings_str << ", ";
+    timings_str << timings[i];
+  }
+  timings_str << "]";
+
+  // Localhost HTTP GET should be fast even in CI environments
+  EXPECT_LE(p25, 5) << "25th percentile performance is too slow: " << p25
+                    << "ms (Issue #1777). Timings: " << timings_str.str();
+}
+
+TEST(BenchmarkTest, localhost) { performance_test("localhost"); }
+
+TEST(BenchmarkTest, v6) { performance_test("::1"); }