when the child process died due to a signal.

lacking os.fork().

signal number when the process died due to a signal.

as Windows that do not support os.fork().

Patch by Emily Morehouse.

This makes the Template tests discoverable.  Patch by Erin Braswell.

Patch by A. Jesse Jiryu Davis

Initial patch by Claudiu Popa.

Patch by Tommy Beadle.

verification and patch by Emily Morehouse.

Patch from A. Skrobov.

We now have two keyword only parameters in the reset_mock function to
selectively reset the return_value or the side_effects, or both.

Patch by Bryce Verdier.