I've got a question about how to share rspec-mocks' double between examples. I'm writing a new rails app with rspec-mocks 3.1.3. I'm used to using the old (< 2.14 and and trying to update my knowledge if current rspec usage.
I have a model method:
def self.from_strava(activity_id, race_id, user)
#client ||= Strava::Api::V3::Client.new(access_token: 'abc123')
activity = #client.retrieve_an_activity(activity_id)
result_details = {race_id: race_id, user: user}
result_details[:duration] = activity['moving_time']
result_details[:date] = Date.parse(activity['start_date'])
result_details[:comment] = activity['description']
result_details[:strava_url] = "http://www.strava.com/activities/#{activity_id}"
Result.create!(result_details)
end
And here is the spec:
describe ".from_strava" do
let(:user) { FactoryGirl.build(:user) }
let(:client) { double(:client) }
let(:json_response) { JSON.parse(File.read('spec/support/strava_response.json')) }
before(:each) do
allow(Strava::Api::V3::Client).to receive(:new) { client }
allow(client).to receive(:retrieve_an_activity) { json_response }
allow(Result).to receive(:create!)
end
it "sets the duration" do
expect(Result).to receive(:create!).with(hash_including(duration: 3635))
Result.from_strava('123', 456, user)
end
it "sets the date" do
expect(Result).to receive(:create!).with(hash_including(date: Date.parse("2014-11-14")))
Result.from_strava('123', 456, user)
end
end
When I run a single test on it's own it's fine, but when I run the whole describe ".from_strava" block it fails with the message
Double :client was originally created in one example but has leaked into another example and can no longer be used. rspec-mocks' doubles are designed to only last for one example, and you need to create a new one in each example you wish to use it for.
I understand what it's saying, but surely this is an appropriate use of a double being used in 2 examples. After all, the client double isn't important to the example, it's just a way for me to load the canned response. I guess I could use WebMock but that seems very low-level and doesn't translate well to the actual code written. We should only be asserting one thing per example after all.
I had thought about replacing the client double with a call to
allow(Strava::Api::V3::Client).to receive_message_chain(:new, :retrieve_an_activity) { json_response }
but that doesn't seem to be the right approach either, given that the documentation states that receive_message_chain should be a code smell.
So if I shouldn't use receive_message_chain, shared client double and also follow the standard DRY principle then how should I fix this?
I would love some feedback on this.
Thanks,
Dave
Caching clients for external components can often be really desired (keeping alive connections/any SSL setup that you might need, etc.) and removing that for the sake of fixing an issue with tests is not a desirable solution.
In order to fix your test (without refactoring your code), you can do the following to clear the instance variable after each of your tests:
after { Result.instance_variable_set("#client", nil) }
While admittedly, this is not the cleanest solution, it seems to be the simplest and achieves both, lets you have a clear setup with no state shared in between tests, and keep your client cached in "normal" operation mode.
surely this is an appropriate use of a double being used in 2 examples.
No, it's not. :) You're trying to use a class variable; do not do that because the variable doesn't span examples. The solution is to set the client each time i.e. in each example.
Bad:
#client ||= Strava::Api::V3::Client.new(access_token: 'abc123')
Good:
#client = Strava::Api::V3::Client.new(access_token: 'abc123')
I had the same use case in an app of mine, and we solved it by extracting the cacheing into a private method and then stubbing that method to return the double (instead of stubbing the new method directly).
For example, in the class under test:
def self.from_strava(activity_id, race_id, user)
activity = strava_client.retrieve_an_activity(activity_id)
...
end
private
def self.strava_client
#client ||= Strava::Api::V3::Client.new(access_token: 'abc123')
end
And in the spec:
let(:client) { double(:client) }
before { allow(described_class).to receive(:strava_client).and_return(client) }
...
TLDR: Add after { order.vendor_service = nil } to balance the before block. Or read on...
I ran into this, and it was not obvious where it was coming from. In order_spec.rb model tests, I had this:
describe 'order history' do
before do
service = double('VendorAPI')
allow(service).to receive(:order_count).and_return(5)
order.vendor_service = service
end
# tests here ..
end
And in my Order model:
def too_many_orders?
##vendor_service ||= VendorAPI.new(key: 'abc', account: '123')
return ##vendor_service.order_count > 10
end
This worked fine when I only ran rspec on order_spec.rb
I was mocking something completely different in order_controller_spec.rb a little differently, using allow_any_instance_of() instead of double and allow:
allow_any_instance_of(Order).to receive(:too_many_orders?).and_return(true)
This, too, tested out fine.
The confounding trouble is that when I ran the full suite of tests, I got the OP's error on the controller mock -- the one using allow_any_instance. This was very hard to track down, as the problem (or at least my solution) lay in the model tests where I use double/allow.
To fix this, I added an after block clearing the class variable ##vendor_service, balancing the before block's action:
describe 'order history' do
before do
service = double('VendorAPI')
allow(service).to receive(:order_count).and_return(5)
order.vendor_service = service
end
after do
order.vendor_service = nil
end
# tests here ..
end
This forced the ||= VendorAPI.new() to use the real new function in later unrelated tests, not the mock object.
Related
I want to test below organizer interactor for, calling the 2 specified interactors without executing the calling interactors('SaveRecord, PushToService') code.
class Create
include Interactor::Organizer
organize SaveRecord, PushToService
end
I found few examples where the overall result of all the interactors logic(record should be saved and pushed to other service) has been tested. But, i dont want to execute the other interactor's logic as they will be tested as part of their separate specs.
1. Is it possible to do so?
2. Which way of testing(testing the overall result/testing only this particular
organizer interactor behavior) is a better practise?
I believe we need to test the interactor organizer for included interactors without executing the included interacors. I am able to find a way stub and test the organizer with below lines
To Stub:
allow(SaveRecord).to receive(:call!) { :success }
allow(PushToService).to receive(:call!) { :success }
To Test:
it { expect(interactor).to be_kind_of(Interactor::Organizer) }
it { expect(described_class.organized).to eq([SaveRecord, PushToService]) }
Found call! method & organized variable from interactor organizer source files where it is trying to call and use internally. Stubbing the call! method and testing the organized variable has fulfilled my requirement.
You can test they are called and the order:
it 'calls the interactors' do
expect(SaveRecord).to receive(:call!).ordered
expect(PushToService).to receive(:call!).ordered
described_class.call
end
See: https://relishapp.com/rspec/rspec-mocks/docs/setting-constraints/message-order
Just iterating over #prem answer.
To Test:
it { expect(interactor).to be_kind_of(Interactor::Organizer) }
it { expect(described_class.organized).to eq([SaveRecord, PushToService]) }
interactor in this case is an instance of the Interactor class, or in Rspec syntax:
let(:interactor) { described_class.new }
I have this code in one of my tests:
it 'returns ids when successful' do
allow_any_instance_of(Importer).to receive(:import).and_return('12589', '12590', '12591', '12592', '12593', '12594')
expect(#dispatcher.run).to eq(['12589', '12590', '12591', '12592', '12593', '12594'])
end
The test fails because it only return the first value:
expected: ["12589", "12590", "12591", "12592", "12593", "12594"]
got: ["12589", "12589", "12589", "12589", "12589", "12589"]
I just saw that #and_return's capability of returning multiple values only works when used with #allow.
What can I do for #allow_any_instance_of to get this behaviour?
EDIT:
The class I am testing is called Dispatcher. It takes an xml file, and splits it into parts concerning exactly one object. Each of those splitted parts is taken by the Importer which returns exactly one ID. The Dispatcher then creates an Array from those Ids. So, no, I am not expecting an array to be returned by the Importer.
The class I am testing, Dispatcher, calls Importer for every file it finds in an input directory.
Here's what should work (intercept importer creation)
class Dispatcher
def run
files.each do |file|
create_importer(file).import
end
end
def create_importer(file)
::Importer.new(file)
end
end
# spec
let(:fake_importer) { ::Importer.new }
before do
allow(#dispatcher).to receive(:create_importer).and_return(fake_importer)
allow(fake_importer).to receive(:import).and_return(your, multiple, values, here)
end
I want to implement an action that calls remote service with RabbitMQ and presents returned data. I implemented this (more as a proof of concept so far) in similar way to example taken from here: https://github.com/baowen/RailsRabbit and it looks like this:
controller:
def rpc
text = params[:text]
c = RpcClient.new('RPC server route key')
response = c.call text
render text: response
end
RabbitMQ RPC client:
class RpcClient < MQ
attr_reader :reply_queue
attr_accessor :response, :call_id
attr_reader :lock, :condition
def initialize()
# initialize exchange:
conn = Bunny.new(:automatically_recover => false)
conn.start
ch = conn.create_channel
#x = ch.default_exchange
#reply_queue = ch.queue("", :exclusive => true)
#server_queue = 'rpc_queue'
#lock = Mutex.new
#condition = ConditionVariable.new
that = self
#reply_queue.subscribe do |_delivery_info, properties, payload|
if properties[:correlation_id] == that.call_id
that.response = payload.to_s
that.lock.synchronize { that.condition.signal }
end
end
end
def call(message)
self.call_id = generate_uuid
#x.publish(message.to_s,
routing_key: #server_queue,
correlation_id: call_id,
reply_to: #reply_queue.name)
lock.synchronize { condition.wait(lock) }
response
end
private
def generate_uuid
# very naive but good enough for code
# examples
"#{rand}#{rand}#{rand}"
end
end
A few tests indicate that this approach works. On the other hand, this approach assumes creating a client (and subscribing to the queue) for every request on this action, which is inefficient according to the RabbitMQ tutorial. So I've got two questions:
Is it possible to avoid creating a queue for every Rails request?
How will this approach (with threads and mutex) interfere with my whole Rails environment? Is it safe to implement things this way in Rails? I'm using Puma as my web server, if it's relevant.
Is it possible to avoid creating a queue for every Rails request?
Yes - there is no need for every single request to have it's own reply queue.
You can use the built-in direct-reply queue. See the documentation here.
If you don't want to use the direct-reply feature, you can create a single reply queue per rails instance. You can use a single reply queue, and have the correlation id help you figure out where the reply needs to go within that rails instance.
How will this approach (with threads and mutex) interfere with my whole Rails environment? Is it safe to implement things this way in Rails?
what's the purpose of the lock / mutex in this code? doesn't seem necessary to me, but i'm probably missing something since i haven't done ruby in about 5 years :)
Say I have the following test
describe "bob" do
subject {
response = get "/expensive_lookup"
JSON.parse(response.body)
}
its(["transaction_id"]) { should == 1 }
its(["order_id"]) { should == 33 }
end
Then for each its() {} the subject will be reevaluated, which in my case it is a very slow lookup.
I could bundle all my tests together in one like
describe "bob" do
subject(res) {
response = get "/expensive_lookup"
JSON.parse(response.body)
}
it "returns the right stuff" do
res["transaction_id"]).should == 1
res["order_id"].should == 33
end
end
But this makes it less obvious which line of the test has failed if there is a failure.
Is there a way I can stop the subject from being reevaluated for each it block?
You can put that in to a before(:all) block. I don't know if that syntax has changed in a new rspec version, but regardless, your test would become this:
before(:all) do
response = get "/expensive_lookup"
#res = JSON.parse(response.body)
end
it "returns the right transaction ID" do
#res["transaction_id"].should == 1
end
# etc
The pro is that the code in the before-all block gets run just once for your spec. The con is that, as you can see, you can't take advantage of the subject; you need to write each more explicitly. Another gotcha is that any data saved to the test database is not part of the transaction and will not be rolled back.
There are two possible source of issues
Network request is slow/prone to fail
You should really mock all you network requests, slow or not.
The gem VCR is excellent. It makes it trivial to run your request once and persist the result for subsequent testing.
Building the immutable subject is slow
If you have multiple it blocks, the subject will be rebuild every time. Assuming you don't modify the subject, you can build it once.
You can use before(:all):
before(:all) { #cache = very_long_computation.freeze }
subject { #cache }
Note: that I call freeze to avoid modifying it by mistake, but of course that's not a deep freeze so you still need to mind what you are doing. If you are mutating your subject, your tests are no longer independent and shouldn't share the subject.
I'm entirely new to Grails and it's testing functions since I started my current job approx 4 months ago. The person who trained me on testing left our group several weeks ago, and now I'm on my own for testing. What I've slowing been discovering is that the way I was trained on how to do Grails integration testing is almost entirely different from the way(s) that I've seen people do it on the forums and support groups. I could really use some guidance on which way is right/best. I'm currently working in Grails 2.4.0, btw.
Here is a sample mockup of an integration test in the style that I was trained on. Is this the right or even the best way that I should be doing it?
#Test
void "test a method in a controller"() {
def fc = new FooController() // 1. Create controller
fc.springSecurityService = [principal: [username: 'somebody']] // 2. Setup Inputs
fc.params.id = '1122'
fc.create() // 3. Call the method being tested
assertEquals "User Not Found", fc.flash.errorMessage // 4. Make assertions on what was supposed to happen
assertEquals "/", fc.response.redirectUrl
}
Since Grails 2.4.0 is used, you can leverage the benefit of using spock framework by default.
Here is sample unit test case which you can model after to write Integration specs.
Note:
Integration specs goes to test/integration
should inherit IntegrationSpec.
Mocking is not needed. #TestFor is not used as compared to unit spec.
DI can be used to full extent. def myService at class level will inject the service in
spec.
Mocking not required for domain entities.
Above spec should look like:
import grails.test.spock.IntegrationSpec
class FooControllerSpec extends IntegrationSpec {
void "test a method in a controller"() {
given: 'Foo Controller'
def fc = new FooController()
and: 'with authorized user'
fc.springSecurityService = [principal: [username: 'somebody']]
and: 'with request parameter set'
fc.params.id = '1122'
when: 'create is called'
fc.create()
then: 'check redirect url and error message'
fc.flash.errorMessage == "User Not Found"
fc.response.redirectUrl == "/"
}
}