DOC: Replace nose with pytest in the docs

Author: effigies

doc/source/devel/advanced_testing.rst

@@ -25,7 +25,7 @@ Long-running tests
 Long-running tests are not enabled by default, and can be resource-intensive. To run these tests:
 
 * Set environment variable ``NIPY_EXTRA_TESTS=slow``;
-* Run ``nosetests``.
+* Run ``pytest nibabel``.
 
 Note that some tests may require a machine with >4GB of RAM.
 

doc/source/devel/make_release.rst

@@ -79,7 +79,7 @@ Release checklist
 
 * Make sure all tests pass (from the nibabel root directory)::
 
-    nosetests --with-doctest nibabel
+    pytest --doctest-modules nibabel
 
 * Make sure you are set up to use the ``try_branch.py`` - see
   https://github.com/nipy/nibotmi/blob/master/install.rst#trying-a-set-of-changes-on-the-buildbots

doc/source/installation.rst

@@ -90,7 +90,7 @@ Requirements
 *  h5py_ (optional, for MINC2 support)
 *  PyDICOM_ 0.9.9 or greater (optional, for DICOM support)
 *  `Python Imaging Library`_ (optional, for PNG conversion in DICOMFS)
-*  nose_ 0.11 or greater and pytest_ (optional, to run the tests)
+*  pytest_ (optional, to run the tests)
 *  sphinx_ (optional, to build the documentation)
 
 Get the development sources
@@ -128,7 +128,7 @@ module to see if everything is fine.  It should look something like this::
     >>>
 
 
-To run the nibabel test suite, from the terminal run ``nosetests nibabel`` or
+To run the nibabel test suite, from the terminal run ``pytest nibabel`` or
 ``python -c "import nibabel; nibabel.test()``.
 
 To run an extended test suite that validates ``nibabel`` for long-running and