Installing Graphviz

.travis.yml

@@ -17,6 +17,7 b' install:'
     - pip install setuptools pip --upgrade
     - pip install -e file://$PWD#egg=ipython[test] --upgrade
     - pip install codecov --upgrade
+    - sudo apt-get install graphviz
 script:
     - cd /tmp && iptest --coverage xml && cd -
     # On the latest Python only, make sure that the docs build.

docs/source/conf.py

@@ -57,6 +57,7 b' extensions = ['
     'sphinx.ext.doctest',
     'sphinx.ext.inheritance_diagram',
     'sphinx.ext.intersphinx',
+    'sphinx.ext.graphviz',
     'IPython.sphinxext.ipython_console_highlighting',
     'IPython.sphinxext.ipython_directive',
     'sphinx.ext.napoleon',  # to preprocess docstrings