NoMethodError when using RubyEventStore::RSpec::Publish matcher with InMemoryRepository and preceding events

[silvabox]

When using the Publish matcher in the following manner:

before do
  # some code that publishes an event to `other_event_stream`
end

# ...

expect { subject }.to publish(SomeEvent)
  .in(event_store)
  .in_stream(stream_name)

...using the InMemoryRepository, we get the error NoMethodError: undefined method '+' for nil:NilClass.

This happens as a result of the call in Publish:

      def matches?(event_proc)
        fetch_events.from_last
        event_proc.call
        stream_names.all? do |stream_name|
          fetch_events.stream(stream_name)

The initial call to fetch_events.from_last will set the spec.start to an event_id from an arbitrary stream published to in the preamble (in this example a before block. A let! block has the same effect).
The subsequent fetch_events.stream(stream_name) then causes an error in InMemoryRepository:153:

      serialized_records = serialized_records.drop(index_of(serialized_records, spec.start) + 1) if spec.start

since index_of(serialized_records, spec.start) is nil (i.e. nil + 1)

I would propose that if the event specified in spec.start is not present in serialized_records, then it should simply iterate from the beginning of the collection.

[pjurewicz]

Hello @silvabox! Thank you very much for sharing this problem.
I've just managed to reproduce your case with this simple test:

      specify do
        event_store.publish(FooEvent.new, stream_name: "Foo$1")
        expect do
          event_store.publish(FooEvent.new, stream_name: "Foo$2")
        end.to publish(FooEvent)
                 .in(event_store)
                 .in_stream("Foo$2")
      end

We are working on a fix.

[silvabox]

That's fantastic, thank you @pjurewicz for responding so quickly 😌

[pjurewicz]

Hello @silvabox
This issue is resolved in ruby_event_store-rspec version 2.12.0.
Thank you again