split metric tests into separate files

move FakeResult and MockShellComamd to new file, move DiskMetricTest to
own file, change test_main so that it looks for all files *_test.py in
tests/

Bug: None
Test: None
Change-Id: I7802446a743b3b0bb50f742145f3f43f7c080b6b
3 files changed
tree: 20ea6ea35259a10ea1d971b5536a1663ceee8279
  1. acts/
  2. tools/
  3. Android.mk
  4. PREUPLOAD.cfg