Log Message:
py-test: updated to 3.8.0

pytest 3.8.0:

Deprecations and Removals
- Config.warn has been deprecated, it should be replaced by calls to the \ 
standard warnings.warn.
  Node.warn now supports two signatures:
  * node.warn(PytestWarning("some message")): is now the recommended \ 
way to call this function. The warning
    instance must be a PytestWarning or subclass  instance.
  * node.warn("CI", "some message"): this code/message form \ 
is now deprecated and should be converted to
    the warning instance form above.
  RemovedInPytest4Warning and PytestExperimentalApiWarning are now part of the \ 
public API and should be accessed
  using pytest.RemovedInPytest4Warning and pytest.PytestExperimentalApiWarning.
- @pytest.mark.filterwarnings second parameter is no longer regex-escaped,
  making it possible to actually use regular expressions to check the warning \ 
message.
  **Note**: regex-escaping the match string was an implementation oversight that \ 
might break test suites which depend
  on the old behavior.

Features
- Internal pytest warnings are now issued using the standard warnings module, \ 
making it possible to use
  the standard warnings filters to manage those warnings. This introduces \ 
PytestWarning,
  PytestDeprecationWarning and RemovedInPytest4Warning warning types as part of \ 
the public API.
- DeprecationWarning and PendingDeprecationWarning are now shown by default if \ 
no other warning filter is
  configured.
- Add option to disable plugin auto-loading.
- Added the count option to console_output_style to enable displaying the \ 
progress as a count instead of a percentage.
- Added support for 'xfailed' and 'xpassed' outcomes to the \ 
pytester.RunResult.assert_outcomes signature.
- Terminal writer now takes into account unicode character width when writing \ 
out progress.
- Pytest now returns with correct exit code (EXIT_USAGEERROR, 4) when called \ 
with unknown arguments.
- Improve performance of assertion rewriting.

- Added a blurb in usage.rst for the usage of -r flag which is used to show an \ 
extra test summary info.
- Corrected type of the exceptions collection passed to xfail: raises argument \ 
accepts a tuple instead of list.

Trivial/Internal Changes
- Removed "run all (no recorded failures)" message printed with \ 
--failed-first and --last-failed when there are no failed tests.