Testing Support
===============

The zc.buildout.testing module provides an API that can be used when
writing recipe tests.  This API is documented below.  Many examples of
using this API can be found in the zc.buildout, zc.recipe.egg, and
zc.recipe.testrunner tests.

zc.buildout.testing.buildoutSetUp(test)
---------------------------------------

The buildoutSetup function can be used as a doctest setup function.
It creates a sample buildout that can be used by tests, changing the
current working directory to the sample_buildout. It also adds a
number of names to the test namespace:

``sample_buildout``
    This is the name of a buildout with a basic configuration.

``buildout``
    This is the path of the buildout script in the sample buildout.

``ls(*path)``
    List the contents of a directory.  The directory path is provided as one or
    more strings, to be joined with os.path.join.

``cat(*path)``
    Display the contents of a file.   The file path is provided as one or
    more strings, to be joined with os.path.join.

    On Windows, if the file doesn't exist, the function will try
    adding a '-script.py' suffix.  This helps to work around a
    difference in script generation on windows.

``mkdir(*path)``
    Create a directory. The directory path is provided as one or
    more strings, to be joined with os.path.join.

``rmdir(*path)``
    Remove a directory. The directory path is provided as one or
    more strings, to be joined with os.path.join.

``remove(*path)``
    Remove a directory or file. The path is provided as one or
    more strings, to be joined with os.path.join.

``tmpdir(name)``
    Create a temporary directory with the given name.  The directory
    will be automatically removed at the end of the test.  The path of
    the created directory is returned.

    Further, if the the normalize_path normalizing substitution (see
    below) is used, then any paths starting with this path will be
    normalized to::

      /name/restofpath

    No two temporary directories can be created with the same name.  A
    directory created with tmpdir can be removed with rmdir and recreated.

    Note that the sample_buildout directory is created by calling this
    function.

``write(*path_and_contents)``
    Create a file.  The file path is provided as one or more strings,
    to be joined with os.path.join. The last argument is the file contents.

``system(command, input='')``
    Execute a system command with the given input passed to the
    command's standard input.  The output (error and regular output)
    from the command is returned.

``get(url)``
    Get a web page.

``cd(*path)``
    Change to the given directory.  The directory path is provided as one or
    more strings, to be joined with os.path.join.

    The directory will be reset at the end of the test.

``uncd()``
    Change to the directory that was current prior to the previous
    call to ``cd``. You can call ``cd`` multiple times and then
    ``uncd`` the same number of times to return to the same location.

``join(*path)``
    A convenient reference to os.path.join.

``register_teardown(func)``
    Register a tear-down function.  The function will be called with
    no arguments at the end of the test.

``start_server(path)``
    Start a web server on the given path.  The server will be shut
    down at the end of the test.  The server URL is returned.

    You can cause the server to start and stop logging it's output
    using:

       >>> get(server_url+'enable_server_logging')

    and:

       >>> get(server_url+'disable_server_logging')

    This can be useful to see how buildout is interacting with a
    server.


``sdist(setup, dest)``
    Create a source distribution by running the given setup file and
    placing the result in the given destination directory.  If the
    setup argument is a directory, the setup.py file in that
    directory is used.

``bdist_egg(setup, dest)``
    Create an egg by running the given setup file
    and placing the result in the given destination
    directory.  If the setup argument is a directory, then the
    setup.py file in that directory is used.

Code Coverage Measurement
~~~~~~~~~~~~~~~~~~~~~~~~~

``buildoutSetUp`` prepares a new ``bin/buildout`` executable for
doctests to run. Because this is will run in a subprocess, there are
some extra steps needed to collect code coverage data for buildout and
buildout recipes. This function does most of the heavy lifting for
you, you only need to do a few things.

First, you need to define a coverage configuration ('.coveragerc')
which specifies that multiple different runs should be collected::

    [run]
    source = my.egg.name
    parallel = true

Second, when you invoke the test runner, you need to define the
``COVERAGE_PROCESS_START`` environment variable to point to this
configuration and invoke it with coverage::

    COVERAGE_PROCESS_START=.coveragerc coverage run -m zope.testrunner --test-path=src

Finally, after the tests have finished, you need to combine the
resulting coverage data files and then you can produce reports::

    coverage combine
    coverage report

.. caution:: You must be working in an environment (e.g., a virtual
			 environment) that has coverage already installed.

``zc.buildout.testing.buildoutTearDown(test)``
----------------------------------------------

Tear down everything set up by zc.buildout.testing.buildoutSetUp.  Any
functions passed to register_teardown are called as well.

``install(project, destination)``
---------------------------------

Install eggs for a given project into a destination.  If the
destination is a test object, then the eggs directory of the
sample buildout (sample_buildout) defined by the test will be used.
Tests will use this to install the distributions for the packages
being tested (and their dependencies) into a sample buildout. The egg
to be used should already be loaded, by importing one of the modules
provided, before calling this function.

``install_develop(project, destination)``
-----------------------------------------

Like install, but a develop egg is installed even if the current egg
if not a develop egg.

``Output normalization``
------------------------

Recipe tests often generate output that is dependent on temporary file
locations, operating system conventions or Python versions.  To deal
with these dependencies, we often use
zope.testing.renormalizing.RENormalizing to normalize test output.
zope.testing.renormalizing.RENormalizing takes pairs of regular
expressions and substitutions. The zc.buildout.testing module provides
a few helpful variables that define regular-expression/substitution
pairs that you can pass to zope.testing.renormalizing.RENormalizing.


``normalize_path``
   Converts tests paths, based on directories created with tmpdir(),
   to simple paths.

``normalize_script``
   On Unix-like systems, scripts are implemented in single files
   without suffixes.  On windows, scripts are implemented with 2
   files, a -script.py file and a .exe file.  This normalization
   converts directory listings of Windows scripts to the form
   generated on UNix-like systems.

``normalize_egg_py``
   Normalize Python version and platform indicators, if specified, in
   egg names.
