[qutebrowser] Useful vim function for testing

[Ryan Roden-Corrent]

I've been working with the tests a lot and thought I would share this vim
function in case anyone else finds it useful:

---
function! RunTest()
    if (expand('%:e') == 'feature')
        " this is a .feature file, run the corresponding .py test
        let l:fname = expand('%:h') . '/test_' . expand('%:t:r') . '_bdd.py'
        execute '!tox -e py35 -- ' . l:fname
        let s:last_run = l:fname
    elseif (expand('%:t') =~ 'test_.*\.py$')
        " if this is a test_*.py file, run it directly
        execute '!tox -e py35 -- ' . expand('%')
        let s:last_run = expand('%')
    elseif (exists('s:last_run'))
        " we are not on a test file, so run the test we ran last time
        execute '!tox -e py35 -- ' . s:last_run
    endif
endfunction
nnoremap <F3> :call RunTest()<cr>
---

If the current buffer is 'test_foo.py', it runs that test. If it is
'foo.feature', it runs the corresponding feature test ('test_foo_bdd.py').
Otherwise, it runs whatever test you last ran.

I'm no vimscript wizard so there may very well be some mistakes in there, but it
works for me.

-Ryan