The testing tools (only the code hacker at this time) have been moved
from 'src' to 'tests/Tools', since many opcode cache plugins
load the whole src folder in production.
Also, an extra autoloader is set in the tests bootstrap so that
the 'tests/Tools' directory corresponds, using PSR4, to the
'Automattic\WooCommerce\Testing\Tools' namespace.
Nestor Soriano