Add a spack testing module

index.rst

@@ -91,4 +91,5 @@ Full contents:
    tutorial_spack_scripting
    tutorial_modules
    tutorial_buildsystems
+   tutorial_testing
    tutorial_advanced_packaging

outputs/testing/cleanup.out

@@ -0,0 +1,3 @@
+$ spack repo remove spack-tests
+==> Removed repository /home/spack/spack/var/spack/repos/spack-tests with namespace 'spack-tests'.
+$ rm -rf $SPACK_ROOT/var/spack/repos/spack-tests

outputs/testing/repo-add.out

@@ -0,0 +1,2 @@
+$ spack repo add $SPACK_ROOT/var/spack/repos/spack-tests/
+==> Added repo with namespace 'tutorial'.

tutorial_testing.rst

@@ -0,0 +1,60 @@
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
+   Spack Project Developers. See the top-level COPYRIGHT file for details.
+
+   SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+.. include:: common/setup.rst
+
+.. _testing-tutorial:
+
+=========================
+Package Testing Tutorial
+=========================
+
+This tutorial walks you through the steps for adding and running Spack
+package tests during and after the software installation process. A package
+that *appears* to install successfully may not actually be installed
+correctly or continue to work indefinitely. There are a number of possible
+reasons. For example, the installation process may not have fully installed
+the software. The installed software may not work. Or the software may
+work right after it is installed but, due to system changes, it stops
+working days, weeks, or months later. So Spack provides features for
+`checking installed software
+<https://spack-tutorial.readthedocs.io/en/latest/tutorial_packaging.html>`_
+
+Recall from `Package Creation
+<https://spack-tutorial.readthedocs.io/en/latest/tutorial_packaging.html>`_
+that Spack packages are installation scripts, or recipes, for building
+software. As such, they are well suited for also encapsulating recipes
+for testing the installed software.
+
+Tests can be performed at two points in the life of an installed 
+package:  build-time and stand-alone. **Build-time** tests run as
+part of the package installation process. **Stand-alone** tests run
+at any point after the software is installed.
+
+---------------
+Getting started
+---------------
+
+In order to avoid modifying your Spack instance with changes from this
+tutorial, let's add a package repository called ``spack-tests``:
+
+.. literalinclude:: outputs/testing/repo-add.out
+   :language: console
+
+Doing this ensures changes we make here do not adversely affect other
+parts of the tutorial. You can find out more about repositories at
+`Package Repositories <https://spack.readthedocs.io/en/latest/repositories.html>`_.
+
+-----------
+Cleaning up
+-----------
+
+Before leaving, let's ensure what we have done does not interfere with your
+Spack instance or future sections of the tutorial. Undo the work by entering
+the following commands:
+
+.. literalinclude:: outputs/testing/cleanup.out
+   :language: console
+