First RSPEC test, ensure value is 1 or -1

Question

New programmer here. I am a student working on my project that is a Reddit clone. Currently I have been introduced to RSPEC. I have to start writing my own Model tests to be used in further exercises. The model in question is not created, it will be in the next assignment. Can someone please check if I have done this correctly?

In the next checkpoint, we'll add a Vote model. This model will feature an inclusion validation. Inclusion validation ensures that a vote's value attribute is either 1 or -1. If a vote is initialized with any other value, it will not save.

1. Create VoteSpec:

spec/models/vote_spec.rb

describe Vote do
  describe "validations" do
    describe "value validation" do
      it "only allows -1 or 1 as values" do
        # your expectations here
      end
    end
  end
end

Write a spec that asserts the validations work as expected.

Use RSpec's expect().to eq() syntax. As you may recall from the specs in the Ruby exercises, you can assert that something should equal false or true.

You won't be able to run the tests because we haven't generated the model we're testing.

Below is my implementation:

describe Vote do
  describe "validations" do

    before do     
      2.times { @vote.create(value: 1) }
      3.times { @vote.create(value: -1) }
      2.times { @vote.create(value: 3) }
    end

    describe "value validation" do 
      it "only allows -1 or 1 as values" do
        expect ( @vote.value ).to eq(-1)
      end

      it "only allows -1 or 1 as values" do
        expect ( @vote.value ).to eq(1)
      end
    end
  end
end

Best regards.

Edit: Here is a revision:

describe Vote do
  describe "validations" do

    before do     
      2.times { Vote.create(value: 1) }
      3.times { Vote.create(value: 0) }
      2.times { Vote.create(value: 3) }
    end

    describe "value validation" do 
      it "only allows -1 as value" do
        expect ( @vote.value ).to eq(-1)
      end
      it "only allows 1 as value" do
        expect ( @vote.value ).to eq(1)
      end

      it "it prohibits other values" do
        expect( @vote.value ).to_not be_valid
      end
    end
  end
end

I have also tried with this code, which worked at first but now fails in the next assignment:

require 'rails_helper'

  describe Vote do
   describe "value validation" do

      it "allows -1" do
        value = Vote.create(value: -1)
        expect(value).to be_valid
      end

      it "allows +1" do
        value = Vote.create(value: +1)
        expect(value).to be_valid
      end

      it "prohibits other values" do
        value = Vote.create(value: 0)
        expect(value).to_not be_valid
      end

    end
end

▶ rspec spec
...FFF

Failures:

  1) Vote value validation allows -1
     Failure/Error: value = Vote.create(value: -1)
     NoMethodError:
       undefined method `update_rank' for nil:NilClass
     # ./app/models/vote.rb:12:in `update_post'
     # ./spec/models/vote_spec.rb:7:in `block (3 levels) in <top (required)>'

  2) Vote value validation allows +1
     Failure/Error: value = Vote.create(value: +1)
     NoMethodError:
       undefined method `update_rank' for nil:NilClass
     # ./app/models/vote.rb:12:in `update_post'
     # ./spec/models/vote_spec.rb:12:in `block (3 levels) in <top (required)>'

  3) Vote value validation prohibits other values
     Failure/Error: expect(value).to eq(false)

       expected: false
            got: #<Vote id: nil, value: 0, user_id: nil, post_id: nil, created_at: nil, updated_at: nil>

       (compared using ==)
     # ./spec/models/vote_spec.rb:18:in `block (3 levels) in <top (required)>'

Finished in 0.30485 seconds (files took 3.28 seconds to load)
6 examples, 3 failures

Failed examples:

rspec ./spec/models/vote_spec.rb:6 # Vote value validation allows -1
rspec ./spec/models/vote_spec.rb:11 # Vote value validation allows +1
rspec ./spec/models/vote_spec.rb:16 # Vote value validation prohibits other values

Answer 1

In this slightly particular case you could just use the absolute value.

 it "only allows -1 or 1 as values" do
    expect ( @vote.value.abs ).to eq(1)
 end