RSpec check the count of an array

Question

I am testing my controller action for practice. In my controller, I just want to get all the distinct products by name from my database:

  def shop
    @products = Product.select('distinct on (name) *').sort_by &:order
  end

I've checked this manually and it works fine. Now I am setting up my test using my RSpec and I want to test that @products is an array greater than 0:

RSpec.describe PagesController, type: :controller do
  describe 'GET #shop' do
    it 'should get all proudcts' do
      get :shop
      expect(assigns(:products).count).to be > 0 
    end
  end
end

Now, I've tried several different combinations of the expect... but it keeps telling me that its either nil or 0, which I know it's not. How can I test that an array is greater 0?

Ursus · Accepted Answer · 2017-12-12 18:22:12Z

23

Try

expect(assigns(:products)).to_not be_empty

This works because the array responds to empty?. Another way could be

expect(assigns(:products).count).to be_positive

Because integers respond to positive?

While if you wanted to check an actual count

expect(assigns(:products).count).to eq 1

edited Dec 12, 2017 at 18:22

answered Dec 12, 2017 at 18:13

Ursus

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2 Comments

Daniel Westendorf Over a year ago

Alternatively to these options, you can create your own matcher. Here is an example. gist.github.com/danielwestendorf/…

Darkisa Over a year ago

Thanks Ursus. I actually found the problem. I didn't seed my test database with data so I had it right, just didn't set everything up right. smh.

schmijos · Accepted Answer · 2020-08-18 07:34:39Z

4

You could also turn it around a bit into the following:

expect(assigns(:products)).to have_attributes(count: be_positive)

This allows you to use subject, like this for example:

subject { assigns(:products) }

it { is_expected.to have_attributes(count: be_positive) }

answered Aug 18, 2020 at 7:34

schmijos

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1 Comment

akostadinov Over a year ago

better answer, because array/object content is shown in exception using this approach

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