```ruby
require 'spec_helper'

describe TWW do
  let(:config) { TWW.config }
  let(:client) { TWW.client }

  it { expect(config).to_not be_nil }
  it { expect(config.from).to eq('ACME Inc.') }
  it { expect(config.username).to eq('acme') }
  it { expect(config.password).to eq('valid') }

  it { expect(client).to_not be_nil }
  it { expect(client.config).to eq(config) }
  it { expect(client).to eq(TWW.client) }
end
```

Improve tests for rest impl
user
```ruby
require 'spec_helper'

describe TWW do
  let(:config) { TWW.config }
  let(:client) { TWW.client }

  describe 'config' do
    subject { config }

    it { should_not be_nil }
    it { should eq(TWW.config) }
    it { should eq(client.config) }

    it { expect(config.username).to eq('acme') }
    it { expect(config.password).to eq('valid') }
    it { expect(config.from).to eq('ACME Inc.') }
  end

  describe 'client' do
    subject { client }

    it { should_not be_nil }
    it { should eq(TWW.client) }
  end
end
```
assistant