Test etcd client from forked child process

Signed-off-by: Tao He <sighingnow@gmail.com>

.github/workflows/build-test.yml

@@ -226,6 +226,9 @@ jobs:
           echo "Run the etcd election test ........................."
           ./build/bin/ElectionTest
 
+          echo "Run the etcd with fork test ........................."
+          ./build/bin/ForkTest
+
           killall -TERM etcd || true
           sleep 5
 

tst/ForkTest.cpp

@@ -0,0 +1,44 @@
+#define CATCH_CONFIG_MAIN
+#include <catch.hpp>
+
+#include <unistd.h>
+
+#include <atomic>
+#include <chrono>
+#include <cstdlib>
+#include <iostream>
+#include <thread>
+
+#include "etcd/Client.hpp"
+#include "etcd/KeepAlive.hpp"
+
+static const std::string etcd_url("http://127.0.0.1:2379");
+
+TEST_CASE("fork: set in child and get from self")
+{
+  pid_t pid = fork();
+  REQUIRE(pid >= 0);
+
+  if (pid == 0) {
+    // child
+    etcd::Client etcd(etcd_url);
+    etcd.set("/test/fork-key1", "fork: abcdefgh").wait();
+    std::cout << "child: set finished ..." << std::endl;
+  } else {
+    // self
+    etcd::Client etcd(etcd_url);
+    size_t check = 0;
+    while (check < 10) {
+        auto resp = etcd.get("/test/fork-key1").get();
+        if (!resp.is_ok()) {
+            check += 1;
+            std::this_thread::sleep_for(std::chrono::seconds(1));
+            continue;
+        } else {
+            CHECK(resp.value().as_string() == "fork: abcdefgh");
+            break;
+        }
+    }
+    std::cout << "self: get finished ..." << std::endl;
+  }
+}