Refactor Tests

[wingrunr21]

The tests are difficult to read and shouldn't all be in one file. Refactor the tests to more closely match areas of responsibility.

[spacewander]

Hey,guys
I want to add role attribution for form element, to save me from writing :role => 'form' all the time.
It seemed to be a easy job, but after opening bootstrap_form_test.rb, I felt 😱

Therefore I plan to refactor the tests this weekend, in three steps:

1. separate bootstrap_form_test.rb into several files.
2. use helper function to combine expected instead of using raw text.
3. add the role attribution.

Will you offer me any advices on this refactor?

[potenza]

see #141