Presence Validator Test

presence_validator_test.rb

require 'active_record'
require 'rspec'
require 'shoulda-matchers'

class Baz < ActiveRecord::Base
  establish_connection(adapter: 'sqlite3', database: ':memory:')

  validates_presence_of :foo, unless: :bar

  def bar
    # true or false
  end
end

ActiveRecord::Schema.define do
  @connection = Baz.connection
  create_table :bazs do |t|
    t.string :foo
  end
end

RSpec.describe Baz do
  let(:baz) { described_class.new }

  context 'when #bar is true' do
    before do
      allow(baz).to receive(:bar).and_return(true)
    end

    it 'does not validate presence of foo' do
      expect(baz).to_not validate_presence_of(:foo)
    end
  end

  context 'when #bar is false' do
    before do
      allow(baz).to receive(:bar).and_return(false)
    end

    it 'validates presence of foo' do
      expect(baz).to validate_presence_of(:foo)
    end
  end
end