Added pytest validator tests

Author: jonmmease

.circleci/config.yml

@@ -219,4 +219,5 @@ workflows:
       - "python-3.6-optional"
       - "python-3.7-optional"
       - "python-2.7-plot_ly"
+      - "python-3.4-plot_ly"
       - "python-3.7-plot_ly"

tox.ini

@@ -58,6 +58,7 @@ deps=
     six==1.10.0
     pytz==2016.10
     retrying==1.3.3
+    pytest==3.5.1
     optional: numpy==1.11.3
     optional: ipython[all]==5.1.0
     optional: jupyter==1.0.0
@@ -73,30 +74,35 @@ basepython={env:PLOTLY_TOX_PYTHON_27:}
 commands=
     python --version
     nosetests {posargs} -x plotly/tests/test_core
+    pytest _plotly_utils/tests/
 
 [testenv:py34-core]
 basepython={env:PLOTLY_TOX_PYTHON_34:}
 commands=
     python --version
     nosetests {posargs} -x plotly/tests/test_core
+    pytest _plotly_utils/tests/
 
 [testenv:py35-core]
 basepython={env:PLOTLY_TOX_PYTHON_35:}
 commands=
     python --version
     nosetests {posargs} -x plotly/tests/test_core
+    pytest _plotly_utils/tests/
 
 [testenv:py36-core]
 basepython={env:PLOTLY_TOX_PYTHON_36:}
 commands=
     python --version
     nosetests {posargs} -x plotly/tests/test_core
+    pytest _plotly_utils/tests/
 
 [testenv:py37-core]
 basepython={env:PLOTLY_TOX_PYTHON_37:}
 commands=
     python --version
     nosetests {posargs} -x plotly/tests/test_core
+    pytest _plotly_utils/tests/
 
 ; OPTIONAL ENVIRONMENTS
 [testenv:py27-optional]
@@ -115,20 +121,31 @@ commands=
     python --version
     nosetests {posargs} -x plotly/tests/test_core
     nosetests {posargs} -x plotly/tests/test_optional
+    pytest _plotly_utils/tests/
 
 [testenv:py35-optional]
 basepython={env:PLOTLY_TOX_PYTHON_35:}
 commands=
     python --version
     nosetests {posargs} -x plotly/tests/test_core
     nosetests {posargs} -x plotly/tests/test_optional
+    pytest _plotly_utils/tests/
 
 [testenv:py36-optional]
 basepython={env:PLOTLY_TOX_PYTHON_36:}
 commands=
     python --version
     nosetests {posargs} -x plotly/tests/test_core
     nosetests {posargs} -x plotly/tests/test_optional
+    pytest _plotly_utils/tests/
+
+[testenv:py37-optional]
+basepython={env:PLOTLY_TOX_PYTHON_37:}
+commands=
+    python --version
+    nosetests {posargs} -x plotly/tests/test_core
+    nosetests {posargs} -x plotly/tests/test_optional
+    pytest _plotly_utils/tests/
 
 ; Plot.ly environments
 [testenv:py27-plot_ly]