nixos/tests/pdns-recursor: test a DNS query

nixos/tests/pdns-recursor.nix

@@ -1,12 +1,15 @@
 import ./make-test-python.nix ({ pkgs, ... }: {
-  name = "powerdns";
+  name = "powerdns-recursor";
 
   nodes.server = { ... }: {
     services.pdns-recursor.enable = true;
+    services.pdns-recursor.exportHosts= true;
+    networking.hosts."192.0.2.1" = [ "example.com" ];
   };
 
   testScript = ''
     server.wait_for_unit("pdns-recursor")
     server.wait_for_open_port("53")
+    assert "192.0.2.1" in server.succeed("host example.com localhost")
   '';
 })