How to complete the rspec put controller test from scaffold

Question

I'm using scaffolding to generate rspec controller tests. By default, it creates the test as:

  let(:valid_attributes) {
    skip("Add a hash of attributes valid for your model")
  }

  describe "PUT update" do
    describe "with valid params" do
      let(:new_attributes) {
        skip("Add a hash of attributes valid for your model")
      }

      it "updates the requested doctor" do
        company = Company.create! valid_attributes
        put :update, {:id => company.to_param, :company => new_attributes}, valid_session
        company.reload
        skip("Add assertions for updated state")
      end

Using FactoryGirl, I've filled this in with:

  let(:valid_attributes) { FactoryGirl.build(:company).attributes.symbolize_keys }

  describe "PUT update" do
    describe "with valid params" do
      let(:new_attributes) { FactoryGirl.build(:company, name: 'New Name').attributes.symbolize_keys }

      it "updates the requested company", focus: true do
        company = Company.create! valid_attributes
        put :update, {:id => company.to_param, :company => new_attributes}, valid_session
        company.reload
        expect(assigns(:company).attributes.symbolize_keys[:name]).to eq(new_attributes[:name])

This works, but it seems like I should be able to test all attributes, instead of just testing the changed name. I tried changing the last line to:

class Hash
  def delete_mutable_attributes
    self.delete_if { |k, v| %w[id created_at updated_at].member?(k) }
  end
end

  expect(assigns(:company).attributes.delete_mutable_attributes.symbolize_keys).to eq(new_attributes)

That almost worked, but I'm getting the following error from rspec having to do with BigDecimal fields:

   -:latitude => #<BigDecimal:7fe376b430c8,'0.8137713195 830835E2',27(27)>,
   -:longitude => #<BigDecimal:7fe376b43078,'-0.1270954650 1027958E3',27(27)>,
   +:latitude => #<BigDecimal:7fe3767eadb8,'0.8137713195 830835E2',27(27)>,
   +:longitude => #<BigDecimal:7fe3767ead40,'-0.1270954650 1027958E3',27(27)>,

Using rspec, factory_girl, and scaffolding is incredibly common, so my questions are:

What is a good example of an rspec and factory_girl test for a PUT update with valid params? Is it necessary to use attributes.symbolize_keys and to delete the mutable keys? How can I get those BigDecimal objects to evaluate as eq?

Solution 1

Ok so this is how I do, I don't pretend to strictly follow the best practices, but I focus on precision of my tests, clarity of my code, and fast execution of my suite.

So let take example of a UserController

1- I do not use FactoryGirl to define the attributes to post to my controller, because I want to keep control of those attributes. FactoryGirl is useful to create record, but you always should set manually the data involved in the operation you are testing, it's better for readability and consistency.

In this regard we will manually define the posted attributes

let(:valid_update_attributes) { {first_name: 'updated_first_name', last_name: 'updated_last_name'} }

2- Then I define the attributes I expect for the updated record, it can be an exact copy of the posted attributes, but it can be that the controller do some extra work and we also want to test that. So let's say for our example that once our user updated his personal information our controller automatically add a need_admin_validation flag

let(:expected_update_attributes) { valid_update_attributes.merge(need_admin_validation: true) }

That's also where you can add assertion for attribute that must remain unchanged. Example with the field age, but it can be anything

let(:expected_update_attributes) { valid_update_attributes.merge(age: 25, need_admin_validation: true) }

3- I define the action, in a let block. Together with the previous 2 let I find it makes my specs very readable. And it also make easy to write shared_examples

let(:action) { patch :update, format: :js, id: record.id, user: valid_update_attributes }

4- (from that point everything is in shared example and custom rspec matchers in my projects) Time to create the original record, for that we can use FactoryGirl

let!(:record) { FactoryGirl.create :user, :with_our_custom_traits, age: 25 }

As you can see we manually set the value for age as we want to verify it did not change during the update action. Also, even if the factory already set the age to 25 I always overwrite it so my test won't break if I change the factory.

Second thing to note: here we use let! with a bang. That is because sometimes you may want to test your controller's fail action, and the best way to do that is to stub valid? and return false. Once you stub valid? you can't create records for the same class anymore, therefor let! with a bang would create the record before the stub of valid?

5- The assertions itself (and finally the answer to your question)

before { action }
it {
  assert_record_values record.reload, expected_update_attributes
  is_expected.to redirect_to(record)
  expect(controller.notice).to eq('User was successfully updated.')
}

Summarize So adding all the above, this is how the spec looks like

describe 'PATCH update' do
  let(:valid_update_attributes) { {first_name: 'updated_first_name', last_name: 'updated_last_name'} }
  let(:expected_update_attributes) { valid_update_attributes.merge(age: 25, need_admin_validation: true) }
  let(:action) { patch :update, format: :js, id: record.id, user: valid_update_attributes }
  let(:record) { FactoryGirl.create :user, :with_our_custom_traits, age: 25 }
  before { action }
  it {
    assert_record_values record.reload, expected_update_attributes
    is_expected.to redirect_to(record)
    expect(controller.notice).to eq('User was successfully updated.')
  }
end

---

assert_record_values is the helper that will make your rspec simpler.

def assert_record_values(record, values)
  values.each do |field, value|
    record_value = record.send field
    record_value = record_value.to_s if (record_value.is_a? BigDecimal and value.is_a? String) or (record_value.is_a? Date and value.is_a? String)

    expect(record_value).to eq(value)
  end
end

As you can see with this simple helper when we expect for a BigDecimal, we can just write the following, and the helper do the rest

let(:expected_update_attributes) { {latitude: '0.8137713195'} }

---

So at the end, and to conclude, when you have written your shared_examples, helpers, and custom matchers, you can keep your specs super DRY. As soon as you start repeating the same thing in your controllers specs find how you can refactor this. It may take time at first, but when its done you can write the tests for a whole controller in few minutes

---

And a last word (I can't stop, I love Rspec) here is how my full helper look like. It is usable for anything in fact, not just models.

def assert_records_values(records, values)
  expect(records.length).to eq(values.count), "Expected <#{values.count}> number of records, got <#{records.count}>\n\nRecords:\n#{records.to_a}"
  records.each_with_index do |record, index|
    assert_record_values record, values[index], index: index
  end
end

def assert_record_values(record, values, index: nil)
  values.each do |field, value|
    record_value = [field].flatten.inject(record) { |object, method| object.try :send, method }
    record_value = record_value.to_s if (record_value.is_a? BigDecimal and value.is_a? String) or (record_value.is_a? Date and value.is_a? String)

    expect_string_or_regexp record_value, value,
                            "#{"(index #{index}) " if index}<#{field}> value expected to be <#{value.inspect}>. Got <#{record_value.inspect}>"
  end
end

def expect_string_or_regexp(value, expected, message = nil)
  if expected.is_a? String
    expect(value).to eq(expected), message
  else
    expect(value).to match(expected), message
  end
end

Solution 2

This is the questioner posting. I had to go down the rabbit hole a bit in understanding multiple, overlapping issues here, so I just wanted to report back on the solution I found.

tldr; It's too much trouble trying to confirm that every important attribute comes back unchanged from a PUT. Just check that the changed attribute is what you expect.

The issues I encountered:

1. FactoryGirl.attributes_for does not return all values, so FactoryGirl: attributes_for not giving me associated attributes suggests using (Factory.build :company).attributes.symbolize_keys, which winds up creating new problems.
2. Specifically, Rails 4.1 enums show as integers instead of enum values, as reported here: https://github.com/thoughtbot/factory_girl/issues/680
3. It turns out that the BigDecimal issue was a red herring, caused by a bug in the rspec matcher which produces incorrect diffs. This was established here: https://github.com/rspec/rspec-core/issues/1649
4. The actual matcher failure is caused by Date values that don't match. This is due to the time returned being different, but it doesn't show because Date.inspect does not show milliseconds.
5. I got around these problems with a monkey patched Hash method that symbolizes keys and stringifes values.

Here's the Hash method, which could go in rails_spec.rb:

class Hash
  def symbolize_and_stringify
    Hash[
      self
      .delete_if { |k, v| %w[id created_at updated_at].member?(k) }
      .map { |k, v| [k.to_sym, v.to_s] }
    ]
  end
end

Alternatively (and perhaps preferably) I could have written a custom rspec matcher than iterates through each attribute and compares their values individually, which would have worked around the date issue. That was the approach of the assert_records_values method at the bottom of the answer I selected by @Benjamin_Sinclaire (for which, thank you).

However, I decided instead to go back to the much, much simpler approach of sticking with attributes_for and just comparing the attribute I changed. Specifically:

  let(:valid_attributes) { FactoryGirl.attributes_for(:company) }
  let(:valid_session) { {} }

  describe "PUT update" do
    describe "with valid params" do
      let(:new_attributes) { FactoryGirl.attributes_for(:company, name: 'New Name') }

      it "updates the requested company" do
        company = Company.create! valid_attributes
        put :update, {:id => company.to_param, :company => new_attributes}, valid_session
        company.reload
        expect(assigns(:company).attributes['name']).to match(new_attributes[:name])
      end

I hope this post allows others to avoid repeating my investigations.

Solution 3

Well, I did something that's quite simpler, I'm using Fabricator, but I'm pretty sure it's the same with FactoryGirl:

  let(:new_attributes) ( { "phone" => 87276251 } )

  it "updates the requested patient" do
    patient = Fabricate :patient
    put :update, id: patient.to_param, patient: new_attributes
    patient.reload
    # skip("Add assertions for updated state")
    expect(patient.attributes).to include( { "phone" => 87276251 } )
  end

Also, I'm not sure why you are building a new factory, PUT verb is supposed to add new stuff, right?. And what you are testing if what you added in the first place (new_attributes), happens to exist after the put in the same model.

Solution 4

This code can be used to solve your two issues:

it "updates the requested patient" do
  patient = Patient.create! valid_attributes
  patient_before = JSON.parse(patient.to_json).symbolize_keys
  put :update, { :id => patient.to_param, :patient => new_attributes }, valid_session
  patient.reload
  patient_after = JSON.parse(patient.to_json).symbolize_keys
  patient_after.delete(:updated_at)
  patient_after.keys.each do |attribute_name|
    if new_attributes.keys.include? attribute_name
      # expect updated attributes to have changed:
      expect(patient_after[attribute_name]).to eq new_attributes[attribute_name].to_s
    else
      # expect non-updated attributes to not have changed:
      expect(patient_after[attribute_name]).to eq patient_before[attribute_name]
    end
  end
end

It solves the problem of comparing floating point numbers by converting the values to it string representation using JSON.

It also solves the problem of checking that the new values have been updated but the rest of the attributes have not changed.

In my experience, though, as the complexity grows, the usual thing to do is to check some specific object state instead of "expecting that the attributes I don't update won't change". Imagine, for instance, having some other attributes changing as the update is done in the controller, like "remaining items", "some status attributes"... You would like to check the specific expected changes, that may be more than the updated attributes.

Solution 5

Here is my way of testing PUT. That is a snippet from my notes_controller_spec, the main idea should be clear (tell me if not):

RSpec.describe NotesController, :type => :controller do
  let(:note) { FactoryGirl.create(:note) }
  let(:valid_note_params) { FactoryGirl.attributes_for(:note) }
  let(:request_params) { {} }

  ...

  describe "PUT 'update'" do
    subject { put 'update', request_params }

    before(:each) { request_params[:id] = note.id }

    context 'with valid note params' do
      before(:each) { request_params[:note] = valid_note_params }

      it 'updates the note in database' do
        expect{ subject }.to change{ Note.where(valid_note_params).count }.by(1)
      end
    end
  end
end

---

Instead of FactoryGirl.build(:company).attributes.symbolize_keys, I'd write FactoryGirl.attributes_for(:company). It is shorter and contains only parameters that you specified in your factory.

---

Unfortunately that is all I can say about your questions.

---

P.S. Though if you lay BigDecimal equality check on database layer by writing in style like

expect{ subject }.to change{ Note.where(valid_note_params).count }.by(1)

this may work for you.

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Comments

[Dan Kohn]

Your example, like my first one, validates that one attribute has been correctly updated. However, it doesn't validate that all of the other attributes are unchanged. I'm essentially replacing a whole factory instance with a new instance.

[Dan Kohn]

I'm the questioner; please see the solution I wound up with below.