$ tox -e docs
…
Running Sphinx v1.4.6
making output directory...
loading pickled environment... not yet created
building [mo]: targets for 0 po files that are out of date
building [doctest]: targets for 4 source files that are out of date
updating environment: 4 added, 0 changed, 0 removed
reading sources... [ 25%] api
reading sources... [ 50%] benchmarks
reading sources... [ 75%] index
reading sources... [100%] quickstart

looking for now-outdated files... none found
pickling environment... done
checking consistency... done
running tests...

Document: quickstart
--------------------
1 items passed all tests:
  36 tests in default
36 tests in 1 items.
36 passed and 0 failed.
Test passed.

Document: api
-------------
1 items passed all tests:
  50 tests in default
50 tests in 1 items.
50 passed and 0 failed.
Test passed.

Doctest summary
===============
   86 tests
    0 failures in tests
    0 failures in setup code
    0 failures in cleanup code
build succeeded.