Currently, this tests and its helper function 'isAlmostEqual' uses
plain booleans to signify failures, which means you can't really debug
a failed test. The patch changes the call chain to use annotated
properties all through, which results in messages like:

  Failing almost equal check
  Delta 3.725290298461914e-9 not smaller than 1e-12
  expected: 2.147785408767952e7
   but got: 2.1477854087679517e7

which (IMHO) it's much more readable.

The patch also replaces a 'fail' with 'failTest' in another test.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>