```ruby
require 'helper'

class TestTmuxPowerline < Test::Unit::TestCase
  should "probably rename this file and start testing for real" do
    flunk "hey buddy, you should probably rename this file and start testing for real"
  end
end
```

Check for a correct initialisation of TmuxPowerline
user
```ruby
require 'helper'

class TestTmuxPowerline < Test::Unit::TestCase
  should "raise an exception if a configuration loader is given as nil" do
    assert_raise do
      TmuxPowerline.new nil
    end
  end
end
```
assistant