I'm trying write a test to assert that all defined operations are called on a successful run. I have the operations for a given process defined in a list and resolve them from a container, like so:
class ProcessController
def call(input)
operations.each { |o| container[o].(input) }
end
def operations
['operation1', 'operation2']
end
def container
My::Container # This is a Dry::Web::Container
end
end
Then I test is as follows:
RSpec.describe ProcessController do
let(:container) { My::Container }
it 'executes all operations' do
subject.operations.each do |op|
expect(container[op]).to receive(:call).and_call_original
end
expect(subject.(input)).to be_success
end
end
This fails because calling container[operation_name]
from inside ProcessController
and from inside the test yield different instances of the operations. I can verify it by comparing the object ids. Other than that, I know the code is working correctly and all operations are being called.
The container is configured to auto register these operations and has been finalized before the test begins to run.
How do I make resolving the same key return the same item?
TL;DR - https://dry-rb.org/gems/dry-system/test-mode/
Hi, to get the behaviour you're asking for, you'd need to use the memoize
option when registering items with your container.
Note that Dry::Web::Container
inherits Dry::System::Container
, which includes Dry::Container::Mixin
, so while the following example is using dry-container
, it's still applicable:
require 'bundler/inline'
gemfile(true) do
source 'https://rubygems.org'
gem 'dry-container'
end
class MyItem; end
class MyContainer
extend Dry::Container::Mixin
register(:item) { MyItem.new }
register(:memoized_item, memoize: true) { MyItem.new }
end
MyContainer[:item].object_id
# => 47171345299860
MyContainer[:item].object_id
# => 47171345290240
MyContainer[:memoized_item].object_id
# => 47171345277260
MyContainer[:memoized_item].object_id
# => 47171345277260
However, to do this from dry-web, you'd need to either memoize all objects auto-registered under the same path, or add the # auto_register: false
magic comment to the top of the files that define the dependencies and boot them manually.
Memoizing could cause concurrency issues depending on which app server you're using and whether or not your objects are mutated during the request lifecycle, hence the design of dry-container to not memoize by default.
Another, arguably better option, is to use stubs:
# Extending above code
require 'dry/container/stub'
MyContainer.enable_stubs!
MyContainer.stub(:item, 'Some string')
MyContainer[:item]
# => "Some string"
Side note:
dry-system
provides an injector so that you don't need to call the container manually in your objects, so your process controller would become something like:
class ProcessController
include My::Importer['operation1', 'operation2']
def call(input)
[operation1, operation2].each do |operation|
operation.(input)
end
end
end