Module: Sequent::Test::CommandHandlerHelpers

Defined in:
lib/sequent/test/command_handler_helpers.rb

Overview

Use in tests

This provides a nice DSL for event based testing of your CommandHandler like

given_events InvoiceCreatedEvent.new(args) when_command PayInvoiceCommand(args) then_events InvoicePaidEvent(args)

Example for Rspec config

RSpec.configure do |config|

config.include Sequent::Test::CommandHandlerHelpers

end

Then in a spec

describe InvoiceCommandHandler do

before :each do
  @event_store = Sequent::Test::CommandHandlerHelpers::FakeEventStore.new
  @repository = Sequent::Core::AggregateRepository.new(@event_store)
  @command_handler = InvoiceCommandHandler.new(@repository)
end

it "marks an invoice as paid" do
  given_events InvoiceCreatedEvent.new(args)
  when_command PayInvoiceCommand(args)
  then_events InvoicePaidEvent(args)
end

end

Defined Under Namespace

Classes: FakeEventStore

Instance Method Summary collapse

Instance Method Details

#given_events(*events) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/sequent/test/command_handler_helpers.rb', line 75

def given_events *events
  raise ArgumentError.new("events can not be nil") if events.compact.empty?
  @event_store.given_events(events)
end

#then_events(*events) ⇒ Object 



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# File 'lib/sequent/test/command_handler_helpers.rb', line 87

def then_events *events
  @event_store.stored_events.map(&:class).should == events.map(&:class)
  @event_store.stored_events.zip(events).each do |actual, expected|
    JSON.parse(actual.payload.to_json).should == JSON.parse(expected.payload.to_json) if expected
  end
end

#then_no_events ⇒ Object 



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# File 'lib/sequent/test/command_handler_helpers.rb', line 94

def then_no_events
  then_events
end

#when_command(command) ⇒ Object 



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# File 'lib/sequent/test/command_handler_helpers.rb', line 80

def when_command command
  raise "@command_handler is mandatory when using the #{self.class}" unless @command_handler
  raise "Command handler #{@command_handler} cannot handle command #{command}, please configure the command type (forgot an include in the command class?)" unless @command_handler.handles_message?(command)
  @command_handler.handle_message(command)
  @repository.commit(command)
end