added initial documentation on test suite

docs/source/devguide/workflow.rst

@@ -91,6 +91,50 @@ features and bug fixes. The general steps for contributing are as follows:
 6. After the pull request has been thoroughly vetted, it is merged back into the
    *develop* branch of mit-crpg/openmc.
 
+OpenMC Test Suite
+-----------------
+
+The purpose of this test suite is to ensure that OpenMC compiles using various
+combinations of compiler flags and options and that all user input options can
+be used successfully without breaking the code. The test suite is based on
+regression or integrated testing where different types of input files are
+configured and the full OpenMC code is executed. Results from simulations
+are compared with expected results. The test suite is comprised of many
+build configurations (e.g. debug, mpi, hdf5) and the actual tests which
+reside in sub-directories in the tests directory.
+
+The test suite is designed to integrate with cmake using ctest_. To run the
+full test suite run:
+
+.. code-block:: sh
+
+    python run_tests.py
+
+A subset of build configurations and/or tests can be run. To see how to use
+the script run:
+
+.. code-block:: sh
+
+    python run_tests.py --help
+
+As an example, say we want to run all tests with debug flags only on tests
+that have cone and plot in their name. Also, we would like to run this on
+4 processors. We can run:
+
+.. code-block:: sh
+
+    python run_tests.py -j 4 -C debug -R "cone|plot"
+
+Note that standard regular expression syntax is used for selecting build
+configurations and tests. To print out a list of build configurations, we
+can run:
+
+.. code-block:: sh
+
+    python run_tests.py -p
+
+.. _ctest: http://www.cmake.org/cmake/help/v2.8.8/ctest.html
+
 Private Development
 -------------------