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.
Related
I have a Ruby cli program that can optionally load a user-specified file via require. I would like to unit test this functionality via RSpec. The obvious thing to do is to mock the require and verify that it happened. Something like this:
context 'with the --require option' do
let(:file) { "test_require.rb" }
let(:args) { ["--require", "#{file}"] }
it "loads the specified file"
expect(...something...).to receive(:require).with(file).and_return(true)
command.start(args)
end
end
(That's just typed, not copy/pasted - the actual code would obscure the question.)
No matter what I try, I can't capture the require, even though it's occurring (it raises a LoadError, so I can see that). I've tried a variety of things, including the most obvious:
expect(Kernel).to receive(:require).with(file).and_return(true)
or even:
let(:kernel_class) { class_double('Kernel') }
kernel_class.as_stubbed_const
allow(Kernel).to receive(:require).and_call_original
allow(Kernel).to receive(:require).with(file).and_return(true)
but nothing seems to hook onto the require
Suggestions?
So require is defined by Kernel but Kernel is included in Object so when you call require inside this context it is not necessarily the Kernel module that is processing the statement.
Update
I am not sure if this exactly solves your issue but it does not suffer from the strange behavior exhibited below:
file = 'non-existent-file'
allow(self).to receive(:require).with(file).and_return(true)
expect(self).to receive(:require).with(file)
expect(require file).to eq(true)
Working Example
OLD Answer:
This is incorrect and exists only for posterity due to the up-votes received. Some how works without the allow. Would love it if someone could explain why as I assumed it should raise instead. I believe the issue to be related to and_return where this is not part of the expectation. My guess is we are only testing that self received require, with_file, and that the and_return portion is just a message transmission (thus my updated answer)
You can still stub this like so:
file = 'non-existent-file.rb'
allow_any_instance_of(Kernel).to receive(:require).with(file).and_return(true)
expect(self).to receive(:require).with(file).and_return(true)
require file
Since I am unclear on your exact implementation since you have obfuscated it for the question I cannot solve your exact issue.
Upon submitting a form in Sinatra, I'm coming up with the following error:
App 40327 output: 2018-06-28 02:59:17 - NoMethodError - undefined method `[]' for nil:NilClass:
App 40327 output: /Library/WebServer/Documents/blammo/routes/publish.rb:87:in `block in <class:MyApp>'
The form is a file upload form, and a single text field. Simple. The file goes through, as does the text field. They are both captured just fine.
I submit the params to a method, which is ultimately responsible for generating the error on the following line down the page:
fname = params[:s_single_file_upload][:filename]
The method in question returns fine with a boolean. I've rewritten it a couple of ways and flushed out anything that might trip something I'm
unfamiliar with.
So the params is messed up if this method mentioned above is being called. So fname can't be assigned. I expect the params to be intact
at this point in the code. Is there any destruction if the params are perused before this point? In another language, I've seen params destroyed
in one way or another for some reason, but I'm not sure about Ruby.
I'm not finding any nil:NilClass, but that's exactly what it's reporting. Here's the trigger of this method:
result = Alpha::rf_alpha_sniff(params)
And the module::method:
module Alpha
def self.rf_alpha_sniff(incoming)
qualifiers = %w(alpha bravo charlie delta echo foxtrot)
incoming.delete('captures')
incoming.delete('splat') # take out Mustermann's 'captures' and 'splat'
incoming.delete('s_single_file_upload') # non-perusal 'single_file_upload'
incoming.values.each do |item|
item = item.gsub(" ","_")
Dev::hq_log("item: #{ qualifiers.include?(item.downcase) }")
return true if qualifiers.include?(item.downcase)
end
return false
end
end
So the page progresses fine without this method. When the method is induced any way, the params seem to get screwed up, so the file is pretty much
gone.
How is this method interfering with the params so that it's unavailable later on down the script? I'm expecting it to be fully available everywhere.
Turns out, using incoming.delete was deleting items from the params hash, as it was a reference to the original, instead of using a copy.
So, I have to copy the params by using params.dup (duplicate) so they are not the same object.
Having a view of the params hash post-testing-method, showed me that objects were indeed deleted. Another one solved.
I have this Ruby code in a script:
$dev_input=gets.chomp.downcase!
if $dev_input.include? "/"
check_developer_commands()
else
puts ">>Invalid Command<<"
continuing_dev_mode()
end
The problem is, whenever I try and run the script containing this, I get an error spat back at me that says :
dev_continue_main.rb:3:in 'continuing_dev_mode': undefined method 'include?' for nil:NilClass (NoMethodError)
Any idea what this error might be? I'm pretty sure that this is the proper way to use the .include? method. I've done some research, looked at tutorialspoint.com and some other sites, but they agree that this is the proper way to use this method.
I checked the error message and it confirmed that the third line in this script/my example is the source of the problem, so it's not some other instance of this method throwing an error.
Any thoughts? Please Help!
The problem is that $dev_input is nil. That stems from applying downcase! in defining $dev_input. I don't know why you want to possibly assign nil to $dev_input, and at the same time claim that calling include? on it is the right way. I don't get your intention for doing that, but if you instead had $dev_input = gets.chomp.downcase, then it wouldn't cause such error.
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
Each time I add in the correct code, it gives me the same error due to AboutMethods:0x00000101841a28 number changing each time. It's like its stuck and I don't know how to get out this loop. It worked once, then I went on to the next step, but then it triggered an error after that.
I must not be inputting the correct line of code given from the console?
def test_calling_private_methods_with_an_explicit_receiver
exception = assert_raise(NoMethodError) do
self.my_private_method
end
assert_match "private method `my_private_method' called for #<AboutMethods:0x000001008debf8>", exception.message
end
The AboutMethods:0x000001008debf8 changes each time, not sure how to approach this problem?
AboutMethods:0x... is the output of the inspect method, which usually (and in this case) includes the class name (AboutMethods) and the object id (0x...). The object id is related to the objects location in memory, so it will change every time.
In my experience, there is very little value to checking the string from an exception (it's brittle). However, if you feel the need, use a regex:
assert_match /private method `my_private_method' called for \#\<AboutMethods:.*/