unit tests: replace nose with pytest (#2502)

* Porting: substitute nose with ytest

This huge commit substitutes nose with pytest as a testing system. Things done here:

* deleted external/nose as it is no longer used
* moved mock resources in their own directory 'test/mock/'
* ported two tests (cmd/find, build_system) to pytest native syntax as an example
* build_environment, log: used monkeypatch instead of try/catch
* moved global mocking of fetch_cache to an auto-used fixture
* moved global mocking from test/__init__.py to conftest.py
* made `spack test` a wrapper around pytest
* run-unit-tests: avoid running python 2.6 tests under coverage to speed them up
* use `pytest --cov` instead of coverage run to cut down testing time

* mock/packages_test: moved mock yaml configuration to files instead of leaving it in the code as string literals

* concretize.py: ported tests to native pytest, reverted multiprocessing in pytest.ini as it was creating the wrong report for coveralls

* conftest.py, fixtures: added docstrings

* concretize_preferences.py: uses fixtures instead of subclassing MockPackagesTest

* directory_layout.py: uses fixtures instead of subclassing MockPackagesTest

* install.py: uses fixtures instead of subclassing MockPackagesTest

* optional_deps.py: uses fixtures instead of subclassing MockPackagesTest

optional_deps.py: uses fixtures instead of subclassing MockPackagesTest

* packages.py: uses fixtures instead of subclassing MockPackagesTest

* provider_index.py: uses fixtures instead of subclassing MockPackagesTest

* spec_yaml.py: uses fixtures instead of subclassing MockPackagesTest

* multimethod.py: uses fixtures instead of subclassing MockPackagesTest

* install.py: now uses mock_archive_url

* git_fetch.py: uses fixtures instead of subclassing MockPackagesTest

* hg_fetch.py: uses fixtures instead of subclassing MockPackagesTest

* svn_fetch.py, mirror.py: uses fixtures instead of subclassing MockPackagesTest
repo.py: deleted

* test_compiler_cmd.py: uses fixtures instead of subclassing MockPackagesTest

* cmd/module.py, cmd/uninstall.py: uses fixtures instead of subclassing MockDatabase

* database.py: uses fixtures instead of subclassing MockDatabase, removed mock/database

* pytest: uncluttering fixture implementations

* database: changing the scope to 'module'

* config.py: uses fixtures instead of subclassing MockPackagesTest

* spec_dag.py, spec_semantics.py: uses fixtures instead of subclassing MockPackagesTest

* stage.py: uses fixtures instead of subclassing MockPackagesTest. Removed mock directory

* pytest: added docstrings to all the fixtures

* pytest: final cleanup

* build_system_guess.py: fixed naming and docstrings as suggested by @scheibelp

* spec_syntax.py: added expected failure on parsing multiple specs closes #1976

* Add pytest and pytest-cov to Spack externals.

* Make `spack flake8` ignore externals.

* run-unit-tests runs spack test and not pytest.

* Remove all the special stuff for `spack test`

- Remove `conftest.py` magic and all the special case stuff in `bin/spack`

- Spack commands can optionally take unknown arguments, if they want to
  handle them.

- `spack test` is now a command like the others.

- `spack test` now just delegates its arguments to `pytest`, but it does
  it by receiving unknown arguments and NOT taking an explicit
  help argument.

* Fix error in fixtures.

* Improve `spack test` command a bit.

- Now supports an approximation of the old simple interface
- Also supports full pytest options if you want them.

* Use external coverage instead of pytest-cov

* Make coverage use parallel-mode.

* change __init__.py docs to include pytest

1 files changed, 0 insertions, 190 deletions

diff --git a/lib/spack/external/nose/plugins/__init__.py b/lib/spack/external/nose/plugins/__init__.py
deleted file mode 100644
index 08ee8f3230..0000000000
--- a/lib/spack/external/nose/plugins/__init__.py
+++ /dev/null
@@ -1,190 +0,0 @@
-"""
-Writing Plugins
----------------
-
-nose supports plugins for test collection, selection, observation and
-reporting. There are two basic rules for plugins:
-
-* Plugin classes should subclass :class:`nose.plugins.Plugin`.
-
-* Plugins may implement any of the methods described in the class
-  :doc:`IPluginInterface <interface>` in nose.plugins.base. Please note that
-  this class is for documentary purposes only; plugins may not subclass
-  IPluginInterface.
-
-Hello World
-===========
-
-Here's a basic plugin.  It doesn't do much so read on for more ideas or dive
-into the :doc:`IPluginInterface <interface>` to see all available hooks.
-
-.. code-block:: python
-
-    import logging
-    import os
-
-    from nose.plugins import Plugin
-
-    log = logging.getLogger('nose.plugins.helloworld')
-
-    class HelloWorld(Plugin):
-        name = 'helloworld'
-
-        def options(self, parser, env=os.environ):
-            super(HelloWorld, self).options(parser, env=env)
-
-        def configure(self, options, conf):
-            super(HelloWorld, self).configure(options, conf)
-            if not self.enabled:
-                return
-
-        def finalize(self, result):
-            log.info('Hello pluginized world!')
-
-Registering
-===========
-
-.. Note::
-  Important note: the following applies only to the default
-  plugin manager. Other plugin managers may use different means to
-  locate and load plugins.
-
-For nose to find a plugin, it must be part of a package that uses
-setuptools_, and the plugin must be included in the entry points defined
-in the setup.py for the package:
-
-.. code-block:: python
-
-    setup(name='Some plugin',
-        # ...
-        entry_points = {
-            'nose.plugins.0.10': [
-                'someplugin = someplugin:SomePlugin'
-                ]
-            },
-        # ...
-        )
-
-Once the package is installed with install or develop, nose will be able
-to load the plugin.
-
-.. _setuptools: http://peak.telecommunity.com/DevCenter/setuptools
-
-Registering a plugin without setuptools
-=======================================
-
-It is currently possible to register a plugin programmatically by
-creating a custom nose runner like this :
-
-.. code-block:: python
-
-    import nose
-    from yourplugin import YourPlugin
-
-    if __name__ == '__main__':
-        nose.main(addplugins=[YourPlugin()])
-
-Defining options
-================
-
-All plugins must implement the methods ``options(self, parser, env)``
-and ``configure(self, options, conf)``. Subclasses of nose.plugins.Plugin
-that want the standard options should call the superclass methods.
-
-nose uses optparse.OptionParser from the standard library to parse
-arguments. A plugin's ``options()`` method receives a parser
-instance. It's good form for a plugin to use that instance only to add
-additional arguments that take only long arguments (--like-this). Most
-of nose's built-in arguments get their default value from an environment
-variable.
-
-A plugin's ``configure()`` method receives the parsed ``OptionParser`` options
-object, as well as the current config object. Plugins should configure their
-behavior based on the user-selected settings, and may raise exceptions
-if the configured behavior is nonsensical.
-
-Logging
-=======
-
-nose uses the logging classes from the standard library. To enable users
-to view debug messages easily, plugins should use ``logging.getLogger()`` to
-acquire a logger in the ``nose.plugins`` namespace.
-
-Recipes
-=======
-
-* Writing a plugin that monitors or controls test result output
-
-  Implement any or all of ``addError``, ``addFailure``, etc., to monitor test
-  results. If you also want to monitor output, implement
-  ``setOutputStream`` and keep a reference to the output stream. If you
-  want to prevent the builtin ``TextTestResult`` output, implement
-  ``setOutputSteam`` and *return a dummy stream*. The default output will go
-  to the dummy stream, while you send your desired output to the real stream.
-
-  Example: `examples/html_plugin/htmlplug.py`_
-
-* Writing a plugin that handles exceptions
-
-  Subclass :doc:`ErrorClassPlugin <errorclasses>`.
-
-  Examples: :doc:`nose.plugins.deprecated <deprecated>`,
-  :doc:`nose.plugins.skip <skip>`
-
-* Writing a plugin that adds detail to error reports
-
-  Implement ``formatError`` and/or ``formatFailure``. The error tuple
-  you return (error class, error message, traceback) will replace the
-  original error tuple.
-
-  Examples: :doc:`nose.plugins.capture <capture>`,
-  :doc:`nose.plugins.failuredetail <failuredetail>`
-
-* Writing a plugin that loads tests from files other than python modules
-
-  Implement ``wantFile`` and ``loadTestsFromFile``. In ``wantFile``,
-  return True for files that you want to examine for tests. In
-  ``loadTestsFromFile``, for those files, return an iterable
-  containing TestCases (or yield them as you find them;
-  ``loadTestsFromFile`` may also be a generator).
-
-  Example: :doc:`nose.plugins.doctests <doctests>`
-
-* Writing a plugin that prints a report
-
-  Implement ``begin`` if you need to perform setup before testing
-  begins. Implement ``report`` and output your report to the provided stream.
-
-  Examples: :doc:`nose.plugins.cover <cover>`, :doc:`nose.plugins.prof <prof>`
-
-* Writing a plugin that selects or rejects tests
-
-  Implement any or all ``want*``  methods. Return False to reject the test
-  candidate, True to accept it -- which  means that the test candidate
-  will pass through the rest of the system, so you must be prepared to
-  load tests from it if tests can't be loaded by the core loader or
-  another plugin -- and None if you don't care.
-
-  Examples: :doc:`nose.plugins.attrib <attrib>`,
-  :doc:`nose.plugins.doctests <doctests>`, :doc:`nose.plugins.testid <testid>`
-
-
-More Examples
-=============
-
-See any builtin plugin or example plugin in the examples_ directory in
-the nose source distribution. There is a list of third-party plugins
-`on jottit`_.
-
-.. _examples/html_plugin/htmlplug.py: http://python-nose.googlecode.com/svn/trunk/examples/html_plugin/htmlplug.py
-.. _examples: http://python-nose.googlecode.com/svn/trunk/examples
-.. _on jottit: http://nose-plugins.jottit.com/
-
-"""
-from nose.plugins.base import Plugin
-from nose.plugins.manager import *
-from nose.plugins.plugintest import PluginTester
-
-if __name__ == '__main__':
-    import doctest
-    doctest.testmod()