selftest/devtool: replace file assertTrue/False with assertExists/NotExists
Current osselftest print confusing assertion message when using
self.assertTrue(os.path.exists(filepath)) to test file path,
example of confusing assertion message:
AssertionError: False is not true
Replce assertTrue/assertFalse with assertExists/assertNotExists to test
file path, this will improve assertion message and simplify coding,
self.assertExists(filepath) will print below
AssertionError: <filepath> does not exist
[YOCTO #11356]
Signed-off-by: Yeoh Ee Peng <ee.peng.yeoh@intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
