nixos/tests/headscale: test dns records config

nixos/tests/headscale.nix

@@ -45,6 +45,13 @@ in
               };
               dns = {
                 base_domain = "tailnet";
+                extra_records = [
+                  {
+                    name = "foo.bar";
+                    type = "A";
+                    value = "100.64.0.2";
+                  }
+                ];
                 override_local_dns = false;
               };
             };
@@ -90,5 +97,6 @@ in
     # Check that they are reachable from the tailnet
     peer1.wait_until_succeeds("tailscale ping peer2")
     peer2.wait_until_succeeds("tailscale ping peer1.tailnet")
+    assert (res := peer1.wait_until_succeeds("${lib.getExe pkgs.dig} +short foo.bar").strip()) == "100.64.0.2", f"Domain {res} did not match 100.64.0.2"
   '';
 }