Adding explicit python 3.5.2 test to nox, travis

Python 3.5.2 introduced a bug in typing that was fixed in 3.5.3.
The bug in typing prevents the latest nox from running properly.
Ubuntu 16.04 stopped at python 3.5.2.
To work-around, force an older version of nox when testing 3.5.2

Author: anselor

.travis.yml

@@ -2,6 +2,9 @@ language: python
 
 matrix:
     include:
+        - os: linux
+          python: 3.5.2
+          env: NOXSESSION=tests-3.5.2
         - os: linux
           python: 3.5.3
           env: NOXSESSION=tests-3.5.3
@@ -38,7 +41,7 @@ matrix:
 #            - BREW_INSTALL=python3
 
 install:
-  - pip install flake8 nox
+  - if [[ $TRAVIS_PYTHON_VERSION == 3.5.2 ]]; then pip install flake8 nox==2019.11.9; else pip install flake8 nox; fi
 #  - |
 #    if [[ $TRAVIS_OS_NAME == 'osx' ]]; then
 #      if [[ -n "$BREW_INSTALL" ]]; then

noxfile.py

@@ -14,7 +14,7 @@ def docs(session):
                 '-d', '{}/doctrees'.format(tmpdir), '.', '{}/html'.format(tmpdir))
 
 
-@nox.session(python=['3.5.3', '3.5', '3.6', '3.7', '3.8', '3.9'])
+@nox.session(python=['3.5.2', '3.5.3', '3.5', '3.6', '3.7', '3.8', '3.9'])
 @nox.parametrize('plugin', [None,
                             'ext_test',
                             'template',
@@ -29,10 +29,9 @@ def tests(session, plugin):
         session.install('invoke', 'codecov', 'coverage')
         session.run('codecov')
     else:
-        session.install('invoke', '.')
+        session.install('invoke', './', 'plugins/{}[test]'.format(plugin))
 
         # cd into test directory to run other unit test
-        session.install('plugins/{}[test]'.format(plugin))
         session.run('invoke',
                     'plugin.{}.pytest'.format(plugin.replace('_', '-')),
                     '--junit',

setup.py

@@ -51,13 +51,19 @@
         "mock ; python_version<'3.6'",  # for python 3.5 we need the third party mock module
         'codecov',
         'coverage',
-        'pytest',
+        'pytest>=4.6',
         'pytest-cov',
         'pytest-mock',
     ],
     # development only dependencies:  install with 'pip install -e .[dev]'
     'dev': ["mock ; python_version<'3.6'",  # for python 3.5 we need the third party mock module
-            'pytest', 'codecov', 'pytest-cov', 'pytest-mock', 'nox', 'flake8',
+            "pytest>=4.6",
+            'codecov',
+            'pytest-cov',
+            'pytest-mock',
+            "nox==2019.11.9 ; python_version=='3.5.2'",
+            "nox ; python_version>'3.5.2'",
+            'flake8',
             'sphinx', 'sphinx-rtd-theme', 'sphinx-autobuild', 'doc8',
             'invoke', 'twine>=1.11',
             ]