how to reset expectations on a mocked class method? - ruby

Sorry if this is plain simple. i am new to ruby as well as rspec and it seems rspec is a very 'obscure' world (esp when coming from a .net background).
In my 'spec', i have:
before(:each) do
expect(File).to receive(:exist?).with("dummy.yaml").and_return (true)
end
This works fine for all my 'examples', except one where i want it to return false.
expect(File).to receive(:exist?).with("non_existent.yaml").and_return (false)
This obviously fails my test because although "non_existent.yaml" expectation was met, the "dummy.yaml" was not:
(<File (class)>).exist?("dummy.yaml")
expected: 1 time with arguments: ("dummy.yaml")
received: 0 times
So how can i do a 'Reset' on 'File.exist?' (a class method mock) before i setup the new expectation for it? (... "non_existent.yaml"..)
i googled and it yielded:
RSpec::Mocks.proxy_for(your_object).reset
but this gives me:
NoMethodError:
undefined method `proxy_for' for RSpec::Mocks:Module

I could not find anywhere in the documentation that this is how you should do it, and past behaviors goes to show that this solution might also change in the future, but apparently this is how you can currently do it:
RSpec::Mocks.space.proxy_for(your_object).reset
I would follow #BroiSatse's remark, though, and think about re-designing the tests, aiming to move the expectation from the before block. The before block is meant for setup, as you say, and the setup is a very weird place to put expectations.
I'm not sure how you came to this design, but I can suggest two possible alternatives:
If the test is trivial, and will work anyway, you should create one test with this explicit expectation, while stubbing it for the other tests:
before(:each) do
allow(File).to receive(:exist?).with("dummy.yaml").and_return (true)
end
it "asks if file exists" do
expect(File).to receive(:exist?).with("dummy.yaml").and_return (true)
# do the test...
end
If the expectation should run for every test, since what changes in each scenario is the context, you should consider using shared examples:
shared_examples "looking for dummy.yaml" do
it "asks if file exists" do
expect(File).to receive(:exist?).with("dummy.yaml").and_return (true)
# do the test...
end
end
it_behaves_like "looking for dummy.yaml" do
let(:scenario) { "something which sets the context"}
end
You might also want to ask myron if there is a more recommended/documented solution to reset mocked objects...

This worked for me to unmock a specific method from a class:
mock = RSpec::Mocks.space.proxy_for(MyClass)
mock.instance_variable_get(:#method_doubles)[:my_method].reset
Note: Same logic of
RSpec::Mocks.space.proxy_for(MyClass).reset which resets all methods

Expanding on #Uri Agassi's answer and as I answered on another similar question, I found that I could use RSpec::Mocks.space.registered? to check if a method was a mock, and RSpec::Mocks.space.proxy_for(my_mocked_var).reset to reset it's value.
Here is the example I included in my other answer:
Example: Resetting a mocked value
For example, if we wanted to reset this mock back to it's unmocked
default value, we can use the RSpec::Mocks.space.proxy_for helper to
find our mock, then reset it:
# when
# Rails.configuration.action_controller.allow_forgery_protection == false
# and
# allow(Rails.configuration.action_controller).to receive(:allow_forgery_protection).and_return(true)
RSpec::Mocks.space.registered?(Rails.configuration.action_controller)
# => true
Rails.configuration.action_controller.allow_forgery_protection
# => true
RSpec::Mocks.space.proxy_for(Rails.configuration.action_controller).reset
Rails.configuration.action_controller.allow_forgery_protection
# => false
Notice however that the even though the mock value has been reset, the
mock remains registered?:
RSpec::Mocks.space.registered?(Rails.configuration.action_controller)
# => true

When using "expect_any_instance" I had success using the following method to change the mock (e.g. our example: Putting out a Twitter post and returning a different tweet id)
expect_any_instance_of(Twitter::REST::Client).to receive(:update).and_return(Hashie::Mash.new(id: "12"))
# post tweet
RSpec::Mocks.space.verify_all
RSpec::Mocks.space.reset_all
expect_any_instance_of(Twitter::REST::Client).to receive(:update).and_return(Hashie::Mash.new(id: "12346"))
# post another tweet

Related

Set RAILS_ENV in rspec

Please considering following code:
class MyModel
validate my_validation unless ENV["RAILS_ENV"] == "test"
end
We have a validation that is going to have major effect on HUGE parts of the test-suite. I only want it to be executed in prod, not when running the test suite*... EXCEPT for the actual tests regarding this validation.
So when testing the validation I need to set the ENV["RAILS_ENV"] to something else then test. I tried this in my my_model_spec.rb-file:
it "tests the validation" do
ENV["RAILS_ENV"] = "development"
# Tests the validation..
ENV["RAILS_ENV"] = "test"
end
This sets the variable while in the spec file, BUT where the check is made in my_model.rb the ENV["RAILS_ENV"] still returns "test".
Is there a way to achieve the declaration of ENV["RAILS_ENV"] in the SPEC-file and have that still set when the model code is executed during the example run?
Yes yes, please believe me we have this under control (... I think :D). It is during a maintenance window.
Obligatory:
validate my_validation unless ENV["RAILS_ENV"] == "test"
In 99.9% of cases, this is really not a good idea.
Just felt I needed to make that clear, in case future readers see this post and get funny ideas... (It would be much better to update the test suite to remain valid, e.g. by changing the factories.)
Is there a way to achieve the declaration of ENV["RAILS_ENV"] in the SPEC-file
Yes - you can stub the value:
allow(ENV).to receive(:[]).with('RAILS_ENV').and_return('development')
There are also some other approaches you could consider.
For example, why not call the method directly, for the purpose of running this test?
record = MyModel.new # or using FactoryBot.build / whatever
record.my_validation
Or, you could add a model attribute to forcibly-run the validation:
class MyModel
attr_accessor :run_my_validation
validate my_validation if ENV["RAILS_ENV"] != "test" || run_my_validation
end
# and in the test:
record = MyModel.new # or using FactoryBot.build / whatever
record.run_my_validation = true
expect(record.valid?).to be_true
Yet another approach you could consider, to eliminate rails environment check from the production code, would be to set an environment-specific configuration value. Which, again, you could stub in the spec:
class MyModel
validate my_validation if Rails.configuration.run_my_model_validation
end
# and in the test:
allow(Rails.configuration).to receive(:run_my_model_validation).and_return(true)
Another benefit to the above is that you could enable the validation in development mode, without making any code change to the application.

Rspec - Is it possible to stub a hash

I'm working on some unit tests. One of them use a specific configuration variable as set in my application MyBigApp::Env which looks like:
{:country=>'uk', :another_hosts=>["192.168.99.105"]}
So I access it with MyBigApp::Env.country
However in my unit test I want that country for the test become something.
Using rspec I've seen stub but can't get it to work - any ideas where I'm going wrong:
MyBigApp::Env.stub(:[]).with('country').and_return('gr')
Also tried this (as above shows deprecated):
allow(MyBigApp::Env).to receive('country').and_return('gr')
Infact as a test, I also tried:
my_hash = {:uri=>nil}
allow(my_hash).to receive(:[]).with(:uri).and_return('Over written!')
p my_hash
and that didnt update either - it just returned {:uri=>nil}
As a workaround, at the moment I'm having to save the env var in a temp var in the before(each) block then return it back to the original in the after(each). This feels really risky to me. I'm thinking imagine the service running and someone runs unit tests it could effect the end user in that small instance the test is running.
Any help would be appreciated.
Thanks
Yes it possible, but keep in mind that stub only works when you trigger/call the method that you stubbed/mocked
my_hash = {:uri=>nil}
allow(my_hash).to receive(:[]).with(:uri).and_return('Over written!')
p my_hash[:url] # it will be 'Over written!'
This works for me:
my_hash = {:uri=>nil}
allow(my_hash).to receive(:[]).with(:uri).and_return('Over written!')
expect(my_hash[:uri]).to eq "Over written!"
In your sample test case, you are just calling p my_hash which doesn't actually call the [] method.
In terms of why this isn't working with MyBigApp::Env, well, that really depends on what class it is. Possible whatever method .country is doesn't actually call [].
Really, if you call MyBigApp::Env['country'] and stub MyBigApp::Env to receive [] with 'country', it should work.
In regards to your concern about changing your running application's behavior from the tests ... what kind of tests are these?! Running unit tests against a live production application would be very odd. How do you imagine it would change your production app's code? The Env hash just lives in memory right?
Anyway, you should never have to worry about your tests changing the experience for an 'end user'. Always run tests on a completely quarantined envionment, meaning don't use the same database. Actually, the test database is usually wiped after each test.
Just wanted to suggest a non-stubbing alternative. For example:
def code_under_test
key = 'country'
# ... maybe lots of code
value = MyBigApp::Env[key] # deep inside some classes
# ... lots more code
"This is the #{value}"
end
MyBigApp::Env is hard-coded deep in the code, and the need for stubbing reveals that dependency, and the benefits of OOP encapsulation are lost.
It'd be much easier if this were the case:
def code_under_test(config_vars = MyBigApp::Env)
"This is the #{config_vars['country']}"
end
it 'should return my country value' do
value = previous_code_under_test('country' => 'TEST VALUE')
expect(value).to eq("This is the TEST VALUE")
end
No stubbing required, just plain old method calls.

How to call a method on a local variable in Ruby?

Probably a stupid question but I was following along this article and came across a bit of code I couldn't quite grasp. Here it is:
class CreateArticle
attr_reader :validate_article, :persist_article
def initialize(validate_article, persist_article)
#validate_article = validate_article
#persist_article = persist_article
end
def call(params)
result = validate_article.call(params)
if result.success?
persist_article.call(params)
end
end
end
More specifically, the problematic line is this:
if result.success?
Here's my problem with it: where did the success? method come from? It's not default in Ruby, and result is a local variable, so it should be nearby. But even if it's just omitted in the code sample, where would it have to be defined for that line to work? Everywhere I tried to define it just gave me an 'undefined method' error.
For example, I tried to define it both in the CreateArticle class and in the (only alluded to) ValidateArticle class, the obvious culprits, but no dice.
Update:
The reason I ask is not so much about what success? does as it is because I'm interested in using the pattern in my code. So, for example, my version of the success? method could be just checking whether a value got updated, or an item was inserted into an array. For example, let's say it's just this:
def success? # or self.success?
return true
end
Problem is, I can find no place where I can put this that works. I even created a module just for it and included it into the class, and still it doesn't work (it just returns 'undefined method'). So I'm still at a loss as to where I would have to define such a method so that it would work the way it looks like it should.
It's a method that comes with rails. It checks.for a server response with a 200 code. If it gets a 200 code it returns true else it returns false. Read the rails API docs about it... https://apidock.com/rails/v3.2.3/ActiveResource/Response/success%3F
Actually . success? is a built in ruby method. Check here. What it actually does is checking Stat and returns a boolean.
I did some more digging around the blog and from what I found I suspect that the code is probably making use of the dry-monads gem:
You can explicitly check the type by calling failure? or success? on a monadic value.
It's not explicit in the code excerpt but it's the only thing that makes sense.

Problems with rspec scope in before blocks

I've searched for an answer to this but I just can't seem to figure out what's going wrong. I have an api client test that looks like the following:
module MyTests
describe '#update' do
# using a before(:all) block for setup
before(:all) do
#client1 = Client.new
#initial_payload_state = #client1.update.payload
end
context 'with a known starting payload' do
# The payload is some nasty nested json so I grab an existing one
# and then use a helper method to convert it to a full payload.
# Then I update the client with the new payload. I'm using before(:each)
# so I can get the client into this state for every test.
before(:each) do
#full_payload_state = helper_method(#initial_payload_state)
end
context 'alter_payload_1 works' do
# now that I have the payload in its full state I'd like to alter it to
# produce a certain output
before(:all) do
#new_payload_state = alter_payload_1(#full_payload_state)
end
# I now want to update the client with the altered payload and make sure
# it has the same data. The request and response bodies are formatted slightly
# differently in this case.
it 'works' do
#updated_payload_state = #client1.update(#new_payload_state)
expect(payloads_equal?(#full_payload_state, #new_payload_state).to eq true
end
end
context 'alter_payload_2 works' do
before(:all) do
#new_payload_state = alter_payload_2(#full_payload_state)
end
it 'works' do
#updated_payload_state = #client1.update(#new_payload_state)
expect(payloads_equal?(#full_payload_state, #new_payload_state).to eq true
end
end
In reality, my before block for setup is much longer, so I think it makes sense to keep it that way. I tried to use a before(:each) block so I could have the same known state to start each of the alter_payload contexts. The problem is that with this setup, I get a no method error for this line:
#new_payload_state = alter_payload_1(#full_payload_state)
suggesting that #full_payload_state is nil. I'm certain I've got something wrong with respect to scope, but I'm not sure why or how to fix it. Any help greatly appreciated!
Looks like a scope issue with before(:all).
In general, it's wise to stop using before(:all) because it entangles your tests.
Replace your before(:all) lines with before(:each), and this will make each of your tests independent of the others. This will likely help you find your glitch.

Data driven testing with ruby testunit

I have a very basic problem for which I am not able to find any solution.
So I am using Watir Webdriver with testunit to test my web application.
I have a test method which I would want to run against multiple set of test-data.
While I can surely use old loop tricks to run it but that would show as only 1 test ran which is not what I want.
I know in testng we have #dataprovider, I am looking for something similar in testunit.
Any help!!
Here is what I have so far:
[1,2].each do |p|
define_method :"test_that_#{p}_is_logged_in" do
# code to log in
end
end
This works fine. But my problem is how and where would I create data against which I can loop in. I am reading my data from excel say I have a list of hash which I get from excel something like
[{:name =>abc,:password => test},{:name =>def,:password => test}]
Current Code status:
class RubyTest < Test::Unit::TestCase
def setup
#excel_array = util.get_excel_map //This gives me an array of hash from excel
end
#excel_array.each do |p|
define_method :"test_that_#{p}_is_logged_in" do
//Code to check login
end
end
I am struggling to run the loop. I get an error saying "undefined method `each' for nil:NilClass (NoMethodError)" on class declaration line
You are wanting to do something like this:
require 'minitest/autorun'
describe 'Login' do
5.times do |number|
it "must allow user#{number} to login" do
assert true # replace this assert with your real code and validation
end
end
end
Of course, I am mixing spec and test/unit assert wording here, but in any case, where the assert is, you would place the assertion/expectation.
As this code stands, it will pass 5 times, and if you were to report in story form, it would be change by the user number for the appropriate test.
Where to get the data from, that is the part of the code that is missing, where you have yet to try and get errors.

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