Add equality operator to ShipmentEvent and TrackingResponse

[richardwu]

Useful for writing tests to compare ShipmentEvent and TrackingResponse objects and future use cases.

cc: @jonathankwok @MalazAlamir

[jonathankwok]

Given the number of things you're comparing, I'd prefer it if we separated them by lines, i.e.

name == other.name &&
time == other.time &&
location == other.location &&
...

Alternatively, you could iterate over all of them, like:

attributes = [:name, :time, :location, :message, :type_code]
attributes.all? { |attr| self.public_send(:attr) == other.public_send(:attr) }

[richardwu]

Changed how distinct TrackingResponse and ShipmentEvent objects are created and tested for (objects as attributes do not copy when copying options hash, therefore deep copying was required). A private method compare_shipment_events was needed to compare :shipment_events between TrackResponse objects such that order inside :shipment_events array would not matter. @jonathankwok @MalazAlamir

[jonathankwok]

👏 👏 👏 👏

[jonathankwok]

🔴 tests aren't your fault, remote APIs are being flaky. Merge when 💚 eventually.

[MalazAlamir]

LGTM 🚀