CODEWITHSUNDEEP
ruby-on-railsruby
tfantina
tfantina

Reputation: 804

NoMethodError: undefined method `scan' while running a helper test

I have a helper that truncates a user's full-name to only show their first name. I wrote a little test to just be sure that it works. I'm forcing myself to learn to test rigorously early on, so this may be overkill but I'm trying to learn a bit more about testing various aspects of the application.

application_helper.rb

 module ApplicationHelper

    def truncate_username(user)
        @first_name = user.scan(/\A[a-zA-Z]+/).first
        return @first_name
    end
end

application_helper_test.rb require 'test_helper'

class ApplicationHelperTest < ActionView::TestCase

  setup do
    @usr = users(:travis)
  end

  test "First name should be truncated" do
   assert_equal "Travis", truncate_username(@usr)
  end
end

Every time I try to run this test I get a NoMethodError: 

ERROR["test_First_name_should_be_truncated", ApplicationHelperTest, 0.7588860000250861]
 test_First_name_should_be_truncated#ApplicationHelperTest (0.76s)
NoMethodError:         NoMethodError: undefined method `scan' for #<User:0x007f9dcec71af0>
            app/helpers/application_helper.rb:4:in `truncate_username'
            test/helpers/application_helper_test.rb:11:in `block in <class:ApplicationHelperTest>'

Any ideas on why this is not working? Or perhaps how I could implement this test better.

Upvotes: 0

Views: 647

Answers (1)

mindlis
mindlis

Reputation: 1677

scan is a String method. You are passing your method a User object, which does not have a scan method (unless you define one).

To make it clearer, your method will work if you pass it a string. In this case, that's the user's full name.

def truncate_username(full_name)
    @first_name = full_name.scan(/\A[a-zA-Z]+/).first
    return @first_name
end

You could also consider putting this method directly on the User model. If you define it something like

User.rb

def first_name
   full_name.scan(/\A[a-zA-Z]+/).first
end

(replace full_name with whatever attribute you are storing the user's name to)

you could then instead be calling @user.first_name in your application instead of truncate_username(@user.full_name).

Upvotes: 1

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