[tests] enable subtests with pytest

Change-Id: Icedb12e9f01f2d06403cc226459feed19a11fef7
---
M .travis.yml
M dev-requirements.txt
M tox.ini
3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 72857b6..82ec627 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -48,8 +48,6 @@
 
 install:
   - pip install -U setuptools
-  # Make Travis reinstall default pytest (T255349)
-  - pip uninstall -y pytest
   - pip install -r dev-requirements.txt
   - pip install -r requirements.txt
 
diff --git a/dev-requirements.txt b/dev-requirements.txt
index 8b99ee1..c02f809 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -1,9 +1,10 @@
 # This is a PIP 6+ requirements file for development dependencies
 #
-pytest
+pytest >= 5.3
 pytest-cov >= 2.6.1
 pytest-timeout
 pytest-runner
+pytest-subtests >= 0.3.2
 pytest-attrib>=0.1.3
 # pytest-httpbin needs httpbin needs werkzeug >= 0.14.1
 # Python 3.8 needs werkzeug >= 0.15.5
diff --git a/tox.ini b/tox.ini
index 5878a8e..ac2a916 100644
--- a/tox.ini
+++ b/tox.ini
@@ -240,7 +240,8 @@
 ignore = D105,D211
 
 [pytest]
-minversion = 5.0
+minversion = 5.3
 testpaths = tests
 python_files = *_tests.py
 norecursedirs = archive
+filterwarnings = ignore:A private pytest class or function was used.:PytestDeprecationWarning

