Karafka-Testing is a library that provides rspec helpers, to make testing of Karafka consumers much easier.
Add this gem to your Gemfile in the test group:
group :test do
gem 'karafka-testing'
gem 'rspec'
endand then in your spec_helper.rb file:
require 'karafka/testing/rspec/helpers'
RSpec.configure do |config|
config.include Karafka::Testing::RSpec::Helpers
endOnce included into your RSpec setup, this library will provide you two methods that you can use with your specs:
#karafka_consumer_for- this method will create a consumer instance for the desired topic. It needs to be set as the spec subject.#publish_for_karafka- this method will "send" message to the consumer instance.
Note: Messages sent using the #publish_for_karafka method won't be sent to Kafka. They will be "virtually" delegated to the created consumer instance so your specs can run without Kafka setup.
RSpec.describe InlineBatchConsumer do
# This will create a consumer instance with all the settings defined for the given topic
subject(:consumer) { karafka_consumer_for(:inline_batch_data) }
let(:nr1_value) { rand }
let(:nr2_value) { rand }
let(:sum) { nr1_value + nr2_value }
before do
# Sends first message to Karafka consumer
publish_for_karafka({ 'number' => nr1_value }.to_json)
# Sends second message to Karafka consumer
publish_for_karafka({ 'number' => nr2_value }.to_json)
allow(Karafka.logger).to receive(:info)
end
it 'expects to log a proper message' do
expect(Karafka.logger).to receive(:info).with("Sum of 2 elements equals to: #{sum}")
consumer.consume
end
endFirst, thank you for considering contributing to Karafka Testing! It's people like you that make the open source community such a great community!
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