Test the resolving of multiple hostnames at the same time

tests/dns.cpp

@@ -9,6 +9,8 @@
 TEST_CASE("DNS resolver")
 {
     Resolver resolver;
+    Resolver resolver2;
+    Resolver resolver3;
 
     /**
      * If we are using cares, we need to run a poller loop until each
@@ -36,38 +38,50 @@ TEST_CASE("DNS resolver")
 
     bool success = true;
 
-    auto error_cb = [&success, &hostname, &port](const char* msg)
-      {
-        INFO("Failed to resolve " << hostname << ":" << port << ": " << msg);
-        success = false;
-      };
-    auto success_cb = [&success, &hostname, &port](const struct addrinfo* addr)
-      {
-        INFO("Successfully resolved " << hostname << ":" << port << ": " << addr_to_string(addr));
-        success = true;
-      };
+    const auto error_cb = [&success](const std::string& hostname)
+    {
+        return [&success, hostname](const char *msg)
+        {
+            INFO("Failed to resolve " << hostname << ":" << msg);
+            success = false;
+        };
+    };
+    const auto success_cb = [&success](const std::string& hostname)
+    {
+        return [&success, hostname](const struct addrinfo *addr)
+        {
+            INFO("Successfully resolved " << hostname << ": " << addr_to_string(addr));
+            success = true;
+        };
+    };
 
     hostname = "example.com";
     resolver.resolve(hostname, port,
-                     success_cb, error_cb);
+                     success_cb(hostname), error_cb(hostname));
+    hostname = "poez.io";
+    resolver2.resolve(hostname, port,
+                      success_cb(hostname), error_cb(hostname));
+    hostname = "louiz.org";
+    resolver3.resolve(hostname, port,
+                      success_cb(hostname), error_cb(hostname));
     loop();
     CHECK(success);
 
     hostname = "this.should.fail.because.it.is..misformatted";
     resolver.resolve(hostname, port,
-                     success_cb, error_cb);
+        success_cb(hostname), error_cb(hostname));
     loop();
     CHECK(!success);
 
     hostname = "this.should.fail.because.it.is.does.not.exist.invalid";
     resolver.resolve(hostname, port,
-                     success_cb, error_cb);
+        success_cb(hostname), error_cb(hostname));
     loop();
     CHECK(!success);
 
     hostname = "localhost";
     resolver.resolve(hostname, port,
-                     success_cb, error_cb);
+        success_cb(hostname), error_cb(hostname));
     loop();
     CHECK(success);