How do I make Karma's auto-watch feature pause before running tests?

How do I make Karma's auto-watch feature pause before running tests?

I'm running into what I think is a race condition between Vim saving files
and Karma re-running my Jasmine unit tests. Here's a sequence of four test
runs which demonstrates the symptom (I truncated the extremely long paths
in the error log):
$ karma start karma.conf.js --auto-watch
[... snip a lot of coding and test running ...]
PhantomJS 1.6 (Linux) LOG: 'Running tests at 2013-08-14T08:19:57.252Z'
PhantomJS 1.6 (Linux): Executed 4 of 4 SUCCESS (0.307 secs / 0.013 secs)
PhantomJS 1.6 (Linux) LOG: 'Running tests at 2013-08-14T08:20:09.866Z'
PhantomJS 1.6 (Linux): Executed 4 of 4 SUCCESS (0.288 secs / 0.012 secs)
PhantomJS 1.6 (Linux) LOG: 'Running tests at 2013-08-14T08:20:14.366Z'
PhantomJS 1.6 (Linux) controller should have a breadcrumb after
$routeChangeSuccess FAILED
Error: No module: myapp.question
at /home/rmunn/.../angular.js:1124
at ensure (/home/rmunn/.../angular.js:1065)
at module (/home/rmunn/.../angular.js:1296)
at /home/rmunn/.../angular.js:2806
TypeError: 'undefined' is not an object (evaluating
'rootScope.$broadcast')
at /home/rmunn/.../unit/controllersSpec.js:35
PhantomJS 1.6 (Linux): Executed 4 of 4 (1 FAILED) (0.312 secs / 0.014 secs)
PhantomJS 1.6 (Linux) LOG: 'Running tests at 2013-08-14T08:20:28.588Z'
PhantomJS 1.6 (Linux): Executed 4 of 4 SUCCESS (0.287 secs / 0.013 secs)
The only change I made to trigger these four runs was adding and removing
whitespace from the question.js file; there were no substantial code
changes, but run #3 failed where runs 1, 2, and 4 succeeded.
My Vim configuration is set up to keep backup files, and by default Vim
keeps backup files by renaming the original file and writing a new one.
(Except under certain conditions, which don't apply here). What I think is
going on is that I'm triggering a race condition: Vim renames question.js
(or whatever file I just edited), Karma detects that change and starts
running tests, and because I have so few tests right now, the tests all
run before the Linux process scheduler hands control back to Vim. Once Vim
gets scheduled again, it writes the new contents of question.js, but by
that point it's too late for the Jasmine test that depended on question.js
existing and being non-empty.
I could possibly fix this by configuring Vim not to keep backup files, but
I'd really rather not run that risk. There's a reason I use backup files,
after all. So is there a way to tell Karma "when you detect a file change,
pause for N milliseconds, then run the unit tests"? While it would be a
brute-force solution, it would solve this particular race condition. Or if
anyone has other clever ideas to offer, I'd love to hear those too.