RSpec: Test Helper Method using current

Table of Contents

I’ll introduce the way to test rails helper code that uses current_user method provided by device gem.

Environment

Ruby 2.2.2
Rails 4.1.8
RSpec 3.1.0

Test Target

The function we are going to test is below. It compare the return value of current_user method and user_id given as argument, and check the argument user_id is of current login user or not.

module ExampleHelper
# check if the id is of current user
# ==== Parameter
# * +user_id+
# ==== Return
# Boolean
def is_current_user?(user_id)
if current_user && current_user.id == user_id
return true
end
return false
end
end

module ExampleHelper

# check if the id is of current user

# ==== Parameter

# * +user_id+

# ==== Return

# Boolean

def is_current_user?(user_id)

if current_user && current_user.id == user_id

return true

end

return false

end

Bad Test Code

The following code raise error. Of course, it simply call a method.

require 'rails_helper'
describe ExampleHelper, type: :helper do
let(:user) {
create(:user)
}
describe '#is_current_user?(user_id)' do
describe 'on logging in' do
it 'returns true' do
expect(helper.is_current_user?(user.id)).to be(true)
end
end
end
end

require 'rails_helper'

describe ExampleHelper, type: :helper do

let(:user) {

create(:user)

}

describe '#is_current_user?(user_id)' do

describe 'on logging in' do

it 'returns true' do

expect(helper.is_current_user?(user.id)).to be(true)

end

Problem

The method current_user used in Helper isn’t usable. It’s handled as undefined method.

We can use helper in View component without error, but in test code we can’t. current_user is undefined method.

It can’t be solved by including Devise::TestHelper, or using @current_user directly that is used by current_user method. (Undefined method current_user can’t reach @current_user) .

Good Test Code

Like the following code, use stub in the test code.

require 'rails_helper'
describe ExampleHelper, type: :helper do
let(:user) {
create(:user)
}
describe '#is_current_user?(user_id)' do
describe 'on logging in' do
it 'returns true' do
allow(helper).to receive(:current_user).and_return(user)
expect(helper.is_current_user?(user.id)).to be(true)
end
end
end
end

require 'rails_helper'

describe ExampleHelper, type: :helper do

let(:user) {

create(:user)

}

describe '#is_current_user?(user_id)' do

describe 'on logging in' do

it 'returns true' do

allow(helper).to receive(:current_user).and_return(user)

expect(helper.is_current_user?(user.id)).to be(true)

end

Using stub feature, helper returns user when it’s current_user method is called.

Attention to Stub Generation

If you generate Stub like helper.stub(:current_user).and_return(true), RSpec 3.3 prints WARNING below. It’s old style and deprecated.

Using stub from rspec-mocks’ old :should syntax without explicitly enabling the syntax is deprecated. Use the new :expect syntax or explicitly enable :should instead.