Tweak unit testing documentation.

Author: Jon Wedell

README.rst

@@ -25,12 +25,3 @@ is to read the documentation at `read the docs <https://pynmrstar.readthedocs.or
 
 .. |Wheel| image:: https://img.shields.io/pypi/wheel/pynmrstar.svg
    :target: https://pypi.org/project/PyNMRSTAR
-
-
-Running the unit tests
-----------------------
-
-.. role:: bash(code)
-   :language: bash
-
-if you with to run the unit tests distributed with PyNMR-Star, please see the readme in :bash:`pynmrstar/unit_tests`

docs/index.rst

@@ -15,6 +15,7 @@ Previous python versions (back to 2.6) are supported by the v2 branch
    usage/quick-start
    usage/examples
    usage/full
+   usage/unit-test
    release-notes
 
 

docs/usage/unit-test.rst

@@ -0,0 +1,30 @@
+How to run the unit tests
+=========================
+
+Setup
+-----
+
+All the following commands should be executed from a shell inside the
+PyNMRSTAR distribution folder (``PyNMRSTAR`` not ``PyNMRSTAR/pynmrstar``).
+
+Some parts of the unit test structure are in a git submodule that needs to be
+downloaded separately.
+
+.. code:: bash
+
+   git submodule init
+   git submodule update
+
+Using unit test
+---------------
+
+.. code:: bash
+
+   python3 -m pynmrstar.unit_tests
+
+Using pytest
+------------
+
+.. code:: bash
+
+   pytest