Sample of mock leak between specs

mock_spec.rb

require 'spec_helper'
require "rspec/mocks/standalone" #spec/helpers.rb spec/helpers.rb:1 - without this line rspec prevents us from using mocks in context

class Box
  attr_reader :color

  def initialize
    @color = Color.new
  end
end

class Color
  def name
    :pink
  end
end

describe Box do
  subject { described_class.new }
  context 'green box' do


    before(:context) do
      # Bad - will stay for all specs that executes after this one
      allow_any_instance_of(Color).to receive(:name).and_return(:green)
    end

    describe 'color' do
      it 'is green' do
        color_name = subject.color.name
        expect(color_name).to eq(:green)
      end
    end
  end

  context 'red box' do

    around(:context) do |example|
      # Better - This works, but no good reason to do it here.
      RSpec::Mocks.with_temporary_scope do
        allow_any_instance_of(Color).to receive(:name).and_return(:red)
        example.run
        # Mock clears itself, scope ends 
      end

    end

    describe 'color' do
      it 'is red' do
        color_name = subject.color.name
        expect(color_name).to eq(:red)
      end
    end
  end
end

describe Color do
  subject(:color) { described_class.new }

  describe '#name' do
    it 'is pink' do
      color_name = color.name
      expect(color_name).to eq(:pink)
    end
  end
end