Set up the test extension in cakePHP 1.3

I am maintaining for some years a web application with cakePHP 1.3. I maybe should have already migrated the code to a more recent version of CakePHP, but it is already a quite big application, and I can never find the time for that.
Anyway, I assume that I could already spare some time in my current development cycles (especially in non-regression tests) with the testing extension of cakePHP 1.3. But I didn’t manage to configure properly the extension in order to make the extension work in cake.
The manual says that I should download and install the core test cases of the cakePHP 1.3 version, but I couldn’t find the corresponding repository on github ( I suppose that it could have been moved to somewhere else.

Could anyone send me an address from which I would be able to download them, or a .zip file containing the required files ?

                          Thank very much by advance for any help,  CIMW.