.travis.yml in licensed-2.2.0 vs .travis.yml in licensed-2.3.0

@@ -71,22 +71,28 @@
       script: ./script/test manifest
       env: NAME="manifest"
 
     # python 2.7 tests
     - language: python
-      python:
-        - "2.7"
+      python: 2.7
       before_script: ./script/source-setup/pip
       script: ./script/test pip
       env: NAME="pip"
 
     # python 3.6 tests
     - language: python
-      python:
-        - "3.6"
+      python: 3.6
       before_script: ./script/source-setup/pip
       script: ./script/test pip
       env: NAME="pip"
+
+    - language: python
+      python: 3.6
+      before_script:
+        - pip install pipenv
+        - ./script/source-setup/pipenv
+      script: ./script/test pipenv
+      env: NAME="pipenv"
 
     - language: ruby
       rvm: 2.4.0
       before_script: ./script/source-setup/git_submodule
       script: ./script/test git_submodule