Passing a clearer description to RSpec `its` method - ruby-on-rails

I'm an RSpec newb, but am really loving how easy it is to write the tests and I'm continually refactoring them to be cleaner as I learn new features of RSpec. So, originally, I had the following:
describe Account do
context "when new" do
let(:account) { Account.new }
subject { account }
it "should have account attributes" do
subject.account_attributes.should_not be_nil
end
end
end
I then learned about the its method, so I tried to rewrite it as such:
describe Account do
context "when new" do
let(:account) { Account.new }
subject { account }
its(:account_attributes, "should not be nil") do
should_not be_nil
end
end
end
This fails due to its not accepting 2 arguments, but removing the message works just fine. The issue is that if the test fails, the message under the Failed examples section just says
rspec ./spec/models/account_spec.rb:23 # Account when new account_attributes
which isn't overly helpful.
So, is there a way to pass a message to its, or better yet, have it output a sane message automatically?

You could define an RSpec custom matcher:
RSpec::Matchers.define :have_account_attributes do
match do |actual|
actual.account_attributes.should_not be_nil
end
failure_message_for_should do
"expected account_attributes to be present, got nil"
end
end
describe Account do
it { should have_account_attributes }
end

You can also write: its(:account_attributes) { should_not be_nil }
See https://www.relishapp.com/rspec/rspec-core/v/2-14/docs/subject/attribute-of-subject
Take note that "its" will be extracted from rspec-core to a gem with the release of rspec 3, though.

Looks like a relatively simple monkey-patch will enable what you seek.
Look at the source of the rspec-core gem version you're using. I'm on 2.10.1. In the file lib/rspec/core/subject.rb I see the its method defined.
Here's my patched version - I changed the def line and the line after that.
Caution - this is very likely to be version specific! Copy the method from your version and modify it just like I did. Note that if the rspec-core developers do a major restructuring of the code, the patch may need to be very different.
module RSpec
module Core
module Subject
module ExampleGroupMethods
# accept an optional description to append
def its(attribute, desc=nil, &block)
describe(desc ? attribute.inspect + " #{desc}" : attribute) do
example do
self.class.class_eval do
define_method(:subject) do
if defined?(#_subject)
#_subject
else
#_subject = Array === attribute ? super()[*attribute] : _nested_attribute(super(), attribute)
end
end
end
instance_eval(&block)
end
end
end
end
end
end
end
That patch can probably be put in your spec_helper.rb.
Now the usage:
its("foo", "is not nil") do
should_not be_nil
end
Output on failure:
rspec ./attrib_example_spec.rb:10 # attr example "foo" is not nil
If you omit the second arg, the behavior will be just like the unpatched method.

Related

Avoid excessive rspec nesting with subject, let, and alternative arguments

I'm trying to do some model_spec testing but having trouble with not having to further nest my rspec code. It would be great if in this case, I could just have a set of "it's" instead of having to add context everytime I want to switch the variable var. Here's the following code:
describe "#some_method" do
subject { course.some_method(var) }
context 'given a project' do
let(:var) {random[1]}
it 'returns the one after' do
is_expected.to eq(random[2])
end
context 'being the last' do
let(:vars) {random.last}
it 'returns nil' do
is_expected.to be_nil
end
end
context '...you get the point, being something else' do
let(:vars) { something.else }
it 'returns nil' do
is_expected.to.to be_nil
end
end
end
end
Maybe I'm just stuck in the wrong mode of thinking and someone could think of a better way for me to do this? I've been suggested that I absolutely must use the subject by someone I work for.
At first, I disagreed and thought it was getting a little burdensome but then I figured keeping subject and having let(:var) apply to it was pretty useful...
RSpecs subject is a tool which can be used to make tests more succinct. There are many cases where it makes sense to use the subject:
RSpec.describe User do
# with the help of shoulda-matchers
it { should validate_uniqueness_of :username } # implicit subject
end
RSpec.describe UsersController do
describe '#show' do
it 'is successful' do
get :show
expect(response).to have_http_status :success
end
it 'renders template show' do
get :show
expect(response).to render_template :show
end
end
#vs
describe '#show' do
subject { response }
before { get :show }
it { should have_http_status :success }
it { should render_template :success }
end
end
And there are cases where using subject will hurt the readability and acuity of your tests.
Your college is just plain wrong in insisting that you always use subject.
A good rule of hand is that if you need an it block then you should not be using subject or is_expected.
If you are describing the call signature of a method you should be calling it in your specs in the same way you would in real life.
let(:decorator){ described_class.new(user) }
describe "#link" do
it 'takes a class option' do
expect(decorator.link(class: 'button')).to match /class=\"button/
end
end
I would recommend running rspec with the --format documentation option and checking if the output actually makes sense. This can be quite important once you get 100s of specs as it gets harder to remember what a behavior a spec actually covers.
How about you write it like this?
expect(subject.call(foo)) is not very pretty but it gets rid of the nesting.
describe "#some_method" do
subject { course.method(:some_method) }
it 'returns the one after if given a project' do
expect(subject.call(random[1])).to eq(random[2])
end
it 'returns nil when it is the last' do
expect(subject.call(random.last)).to be_nil
end
it 'returns nil...' do
expect(subject.call(something.else)).to be_nil
end
end

Testing Rails helper with Rspec: undefined local variable or method `request'

I have a helper method that uses 'request' to determine the URL. However, rspec can't seem to find request. I thought request was available to all front-facing tests?
How can I account for the request method in my spec?
Helper Spec
require 'spec_helper'
describe ApplicationHelper do
describe "full_title" do
it "should include the page title" do
expect(full_title("help")).to include('help')
end
end
end
Helper methods
def full_title(page_title)
if staging? # causing the issue
base_title = "Staging"
else
base_title = "Company Name"
end
if page_title.empty?
"#{base_title} | Tag line "
else
"#{base_title} | #{page_title} "
end
end
def staging? # the request here seems to be the problem
request.original_url.include? "staging"
end
Rspec error
Failure/Error: expect(full_title("help")).to include('help')
NameError:
undefined local variable or method `request' for #<RSpec::ExampleGroups::ApplicationHelper_2::FullTitle:0x00000106260078>
Thanks in advance.
First off: request is only available in the controller tests (and even then only in the request specs I think), helper tests are really basic and isolated. Which is good. Your helper code should be really minimal and normally only work on the input it receives.
However this is pretty easily solvable by using stubbing.
So write something like
#note, OP needed to replace 'helper' with 'self'for Rails 4.0.0 and Rspec 3.0
require 'rails_helper'
describe ApplicationHelper do
describe "full_title" do
context "in staging" do
it "should include the page title" do
helper.should_receive(:staging?).and_return(true)
expect(full_title("help")).to include('help')
end
end
context "not in staging" do
it "should include the page title" do
helper.should_receive(:staging?).and_return(false)
expect(full_title("help")).to include('help')
end
end
end
end
Which is imho a very clear, and then you write separate tests for your staging? method:
describe "staging?" do
context "when in staging" do
it "returns true" do
helper.stub(:request) { OpenStruct.new(original_url: 'staging') }
expect( helper.staging? ).to be true
end
end
context "when not in staging" do
it "returns false" do
helper.stub(:request) { OpenStruct.new(original_url: 'development') }
expect(helper.staging?).to be false
end
end
end
end
Some small remarks: ruby default indentation is 2 spaces.
Secondly, your function now literally says return true if true, ideally it should be written like
def staging?
request.original_url.include? "staging"
end

Change the order of before hooks in rspec

I have a controller spec like this :
describe "#create" do
before { post 'create', params }
context "when the artist is valid" do
before { allow(artist).to receive(:save).and_return(true) }
it { expect(page).to redirect_to(root_path) }
it { expect(notifier).to have_received(:notify) }
end
end
This is a simple spec but It doesn't work because the describe's before block is executed before the context's before block. So, the result of artist.save is not stubed when the create action is called.
It tried to do this :
describe "first describe" do
before { puts 2 }
describe "second describe" do
before { puts 1 }
it "simple spec" do
expect(1).to eq 1
end
end
end
I see the "2" before the "1". I'm not sure but I think it was working with previous versions.
I know, I can do this :
describe "#create" do
context "when the artist is valid" do
before { allow(artist).to receive(:save).and_return(true) }
it "redirect to the root path" do
post 'create', params
expect(page).to redirect_to(root_path)
end
it "do notifications" do
post :create, params
expect(notifier).to have_received(:notify)
end
end
end
But I think it's less clean.
I found, on this page, http://rubydoc.info/github/rspec/rspec-core/RSpec/Core/Hooks#before-instance_method than the order should be this :
before(:suite) # declared in RSpec.configure
before(:all) # declared in RSpec.configure
before(:all) # declared in a parent group
before(:all) # declared in the current group
before(:each) # declared in RSpec.configure
before(:each) # declared in a parent group
before(:each) # declared in the current group
It's not the case on this example.
I'm not sure but I think it was working with older versions of rspec.
Is there a solution?
I would strongly recommend against you changing the order of hooks in rspec. That will make your app non-standard and Rails is build on standards and having things work as expected.
Everything you're describing it "as designed". Outer before blocks are always called before inner blocks.
Your example that you feel is "less clean" is the standard way to do controller specs. I actually encourage you to do it this way so that it is more maintainable/readable. It does not look unclean to me at all.
That said, there are some options:
You can use a method. I have more than once had a method that was do_post or something similar
You can use a let block which is initialized lazily. I would find it unlcean if it relied on other before blocks running first, but it's an option.
You can define subject. https://www.relishapp.com/rspec/rspec-core/v/2-6/docs/subject/explicit-subject

How to test Mass Assignment in Rails 4 using RSpec

Given a simple User model, in Rails 4 with name, email, and an admin boolean, what's the best approach to testing mass assignment using RSpec?
Here's the UsersController:
def create
#user = User.new user_params
...snip
end
private
def user_params
params.require(:user).permit(:name, :email)
end
and two different tries at testing this:
in user_spec.rb
describe "accessible attributes" do
describe "should not allow access to admin" do
before do
#user.admin = "1"
#user.save
end
it { should_not be_admin }
end
end
or in users_controller_spec.rb
it 'should only allow name and email to be set' do
#controller.user_params.keys.should eq(['name', 'email')
end
Neither work - the former just creates a user with admin set to true (failing the test) - presumably this bypasses strong_parameters. The latter works, but only if the user_params method is not private. (The official docs recommend setting it to private. Note - watching for a MassAssignment error in the user_spec doesn't work either (no error is raised).
Note - actually setting the user to admin in a view correctly works - the admin attribute is filtered out and all is happy, but would really like to see this working properly in a test.
An alternative suggest is to use the shoulda-matchers gem with the user_spec.rb:
describe User do
...
it { should_not allow_mass_assignment_of(:admin) }
...
end
(this doesn't work either), giving:
Failure/Error: it { should_not allow_mass_assignment_of(:admin) }
NoMethodError:
undefined method `active_authorizer' for #<Class:0x007f93c9840648>
(I assume this error is due to the fact shoulda-matchers isn't Rails 4 compatible yet).
Thanks in advance!
it "should not allow mass assignment" do
raw_parameters = { :admin => 1 }
parameters = ActionController::Parameters.new(raw_parameters)
expect {#user.update_attributes(parameters)}.should raise_error
end
In order to test mass assignment you should simulate passing parameters from controller.
https://github.com/rails/strong_parameters#use-outside-of-controllers

Rails 3.1, RSpec: testing model validations

I have started my journey with TDD in Rails and have run into a small issue regarding tests for model validations that I can't seem to find a solution to. Let's say I have a User model,
class User < ActiveRecord::Base
validates :username, :presence => true
end
and a simple test
it "should require a username" do
User.new(:username => "").should_not be_valid
end
This correctly tests the presence validation, but what if I want to be more specific? For example, testing full_messages on the errors object..
it "should require a username" do
user = User.create(:username => "")
user.errors[:username].should ~= /can't be blank/
end
My concern about the initial attempt (using should_not be_valid) is that RSpec won't produce a descriptive error message. It simply says "expected valid? to return false, got true." However, the second test example has a minor drawback: it uses the create method instead of the new method in order to get at the errors object.
I would like my tests to be more specific about what they're testing, but at the same time not have to touch a database.
Anyone have any input?
CONGRATULATIONS on you endeavor into TDD with ROR I promise once you get going you will not look back.
The simplest quick and dirty solution will be to generate a new valid model before each of your tests like this:
before(:each) do
#user = User.new
#user.username = "a valid username"
end
BUT what I suggest is you set up factories for all your models that will generate a valid model for you automatically and then you can muddle with individual attributes and see if your validation. I like to use FactoryGirl for this:
Basically once you get set up your test would look something like this:
it "should have valid factory" do
FactoryGirl.build(:user).should be_valid
end
it "should require a username" do
FactoryGirl.build(:user, :username => "").should_not be_valid
end
Here is a good railscast that explains it all better than me:
UPDATE: As of version 3.0 the syntax for factory girl has changed. I have amended my sample code to reflect this.
An easier way to test model validations (and a lot more of active-record) is to use a gem like shoulda or remarkable.
They will allow to the test as follows:
describe User
it { should validate_presence_of :name }
end
Try this:
it "should require a username" do
user = User.create(:username => "")
user.valid?
user.errors.should have_key(:username)
end
in new version rspec, you should use expect instead should, otherwise you'll get warning:
it "should have valid factory" do
expect(FactoryGirl.build(:user)).to be_valid
end
it "should require a username" do
expect(FactoryGirl.build(:user, :username => "")).not_to be_valid
end
I have traditionally handled error content specs in feature or request specs. So, for instance, I have a similar spec which I'll condense below:
Feature Spec Example
before(:each) { visit_order_path }
scenario 'with invalid (empty) description' , :js => :true do
add_empty_task #this line is defined in my spec_helper
expect(page).to have_content("can't be blank")
So then, I have my model spec testing whether something is valid, but then my feature spec which tests the exact output of the error message. FYI, these feature specs require Capybara which can be found here.
Like #nathanvda said, I would take advantage of Thoughtbot's Shoulda Matchers gem. With that rocking, you can write your test in the following manner as to test for presence, as well as any custom error message.
RSpec.describe User do
describe 'User validations' do
let(:message) { "I pitty da foo who dont enter a name" }
it 'validates presence and message' do
is_expected.to validate_presence_of(:name).
with_message message
end
# shorthand syntax:
it { is_expected.to validate_presence_of(:name).with_message message }
end
end
A little late to the party here, but if you don't want to add shoulda matchers, this should work with rspec-rails and factorybot:
# ./spec/factories/user.rb
FactoryBot.define do
factory :user do
sequence(:username) { |n| "user_#{n}" }
end
end
# ./spec/models/user_spec.rb
describe User, type: :model do
context 'without a username' do
let(:user) { create :user, username: nil }
it "should NOT be valid with a username error" do
expect(user).not_to be_valid
expect(user.errors).to have_key(:username)
end
end
end

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