This spec-code

var methodTest = sinon.stub();

methodTest('y');

methodTest.should.have.been.calledOnce
    .and.calledWith('y');

causes

✖ validates each validation
      Chrome 43.0.2357 (Mac OS X 10.9.5)
    TypeError: Cannot read property 'and' of undefined

with [email protected] version.

I've created simple project for bug repro:
https://github.com/AlexKVal/karma-test

master branch uses [email protected] and causes test fail
karma13 https://travis-ci.org/AlexKVal/karma-test/builds/71240835

https://github.com/AlexKVal/karma-test/tree/karma12 branch uses [email protected] version and works fine
karma12 https://travis-ci.org/AlexKVal/karma-test/builds/71240954