Bug 1070845 - [sharedtest] unit test refactoring for new version chai.assert api (rebased)

test_agent used very old version chai library version=0.5.3 in the current version=1.9.1 deepEqua
nit: you don't need `() => done()` here (because the "checkResolve" promise returns nothing). So just use `.then(done, done)`. Same for the other tests below obviously