run-tests: create classes for representing tests
Currently, the state for an individual test is scattered across a number
of functions and variables. This patch begins a process of isolating a
single test's state into instances of a class. It does this by
establishing a new Test base class and child classes for Python tests
and T tests. The class currently has a run() API that proxies into the
existing "runner" functions. Upcoming patches will move the logic for
each test type into the class.
$ hg init
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls
a
unknown