```ruby
require 'honeybadger/backend/test'
require 'honeybadger/config'

describe Honeybadger::Backend::Test do
  let(:config) { Honeybadger::Config.new(logger: NULL_LOGGER) }
  let(:logger) { config.logger }

  let(:instance) { described_class.new(config) }

  subject { instance }

  after do
    Honeybadger::Backend::Test.notifications.clear
  end

  it { should respond_to :notifications }

  describe "#notify" do
    let(:notice) { double('Notice') }

    subject { instance.notify(:notices, double('Notice')) }

    it "saves notifications for review" do
      expect { instance.notify(:notices, notice) }.to change { instance.notifications[:notices] }.from([]).to([notice])
    end

    it { should be_a Honeybadger::Backend::Response }
  end
end
```

Test cached key for test backend.
user
```ruby
require 'honeybadger/backend/test'
require 'honeybadger/config'

describe Honeybadger::Backend::Test do
  let(:config) { Honeybadger::Config.new(logger: NULL_LOGGER) }
  let(:logger) { config.logger }

  let(:instance) { described_class.new(config) }

  subject { instance }

  after do
    Honeybadger::Backend::Test.notifications.clear
  end

  it { should respond_to :notifications }

  describe "#notifications" do
    it "sets a default key value rather than just return one" do
      expect(instance.notifications).not_to have_key(:foo)
      expect(instance.notifications[:foo]).to eq []
      expect(instance.notifications).to have_key(:foo)
    end
  end

  describe "#notify" do
    let(:notice) { double('Notice') }

    subject { instance.notify(:notices, double('Notice')) }

    it "saves notifications for review" do
      expect { instance.notify(:notices, notice) }.to change { instance.notifications[:notices] }.from([]).to([notice])
    end

    it { should be_a Honeybadger::Backend::Response }
  end
end
```
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