Publicado em: 19/Nov/2018
Atualizado em: 16/Dec/2019

Run Tests in Vim

Test driven development thrives on a tight feedback loop but switching from the editor to the shell to manually run specs is inefficient.

Tools such as autotest and guard run specs whenever a file gets saved. Although an improvement over a manual workflow, those approaches often run the suite when not needed and run too many or too few specs.

Enter vim-rspec, a lightweight Vim plugin that runs specs directly from within Vim with the press of a key.

It exposes methods such as RunNearestSpec(), RunCurrentSpecFile(), and RunLastSpec(), which can be bound to a key mapping of your choice. In thoughtbot/dotfiles, we bind those methods to <Leader>s, <Leader>t, and <Leader>l.

Cursor over any line within an RSpec spec like this:

 1describe RecipientInterceptor do
 2  it 'overrides to/cc/bcc fields' do
 3    Mail.register_interceptor
 5    response = deliver_mail
 7    expect( eq [recipient_string]
 8    expect( eq []
 9    expect(response.bcc).to eq []
10  end

Type <Leader>s:

rspec spec/recipient_interceptor_spec.rb:4

Finished in 0.03059 seconds 1 example, 0 failures

The screen is overtaken by a shell that runs only the focused spec. Developers using tmux with vim-rspec and tslime sometimes send the output to a nearby shell so the code and spec output display on the screen at the same time.

Feeling good that this new spec passes, run the whole file’s specs with <Leader>t to make sure the class’s entire functionality is still intact:

rspec spec/recipient_interceptor_spec.rb

Finished in 0.17752 seconds 6 examples, 0 failures

Red, green, refactor. From within the application’s or library’s code:

1def delivering_email(message)
2  add_custom_headers message
3  add_subject_prefix message
4 = @recipients
5 = []
6  message.bcc = []

Run <Leader>l without having to switch back to the spec:

rspec spec/recipient_interceptor_spec.rb

Finished in 0.17752 seconds 6 examples, 0 failures

These tight feedback loops make Test-Driven Development easier by eliminating the switching cost between editor to the shell when running specs.

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