python3-mock binary package in Ubuntu Bionic amd64

 mock provides a core mock.Mock class that is intended to reduce the
 need to create a host of trivial stubs throughout your test suite.
 After performing an action, you can make assertions about which methods
 / attributes were used and arguments they were called with. You can
 also specify return values and set specific attributes in the normal
 way.
 .
 This package contains the Python 3 version of the library.

Source package