Add test for PDU limit on transactions API

tests/50federation/51transactions.pl

@@ -0,0 +1,53 @@
+test "Server correctly handles transactions that break edu limits",
+   requires => [ $main::OUTBOUND_CLIENT, $main::INBOUND_SERVER, $main::HOMESERVER_INFO[0],
+                 local_user_and_room_fixtures(), room_alias_name_fixture() ],
+
+   do => sub {
+      my ( $outbound_client, $inbound_server, $info, $creator, $room_id, $room_alias_name ) = @_;
+
+      my $local_server_name = $info->server_name;
+
+      my $remote_server_name = $inbound_server->server_name;
+
+      my $room_alias = "#$room_alias_name:$remote_server_name";
+
+      $outbound_client->join_room(
+         server_name => $local_server_name,
+         room_id     => $room_id,
+         user_id     => $creator->user_id,
+      )->then( sub {
+         my ( $room ) = @_;
+
+         my $new_event = $room->create_and_insert_event(
+             type => "m.room.message",
+
+             sender  => $creator->user_id,
+             content => {
+                 body => "Message 1",
+             },
+         );
+
+         # Generate two transactions, one that breaks the 50 PDU limit and one
+         # that does not
+         my @bad_pdus = ( $new_event ) x 51;
+         my @good_pdus = ( $new_event ) x 10;
+
+         Future->needs_all(
+            # Send the transaction to the client and expect a fail
+            $outbound_client->send_transaction(
+                pdus => \@bad_pdus,
+                destination => $local_server_name,
+            )->main::expect_http_400(),
+
+            # Send the transaction to the client and expect a succeed
+            $outbound_client->send_transaction(
+                pdus => \@good_pdus,
+                destination => $local_server_name,
+            )->then( sub {
+                my ( $response ) = @_;
+
+                Future->done( 1 );
+            }),
+         );
+      });
+   };