Similar to the approach taken on the previous commits, let's
unwind apply_using and improve its docstrings.

This also new tests for this specific unit of code, and a functional
test.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

The function where this utility method lives is really big and
complex.  Let's break it down for the sake of code readability,
while adding better docstrings.

I've timed the performance changes caused by this, and on most
trials they presented similar performance.

This also adds new tests for this specific unit of code.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

The function where this utility method lives is really big and
complex.  Let's break it down for the sake of code readability,
while adding better docstrings.

I've timed the performance changes caused by this, and on most
trials they presented similar performance.

This also adds new tests for this specific unit of code.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

The function where this utility method lives is really big and
complex.  Let's break it down for the sake of code readability,
while adding better docstrings.  At the same time, this allows
us to write tests for those smaller units.

I've timed the performance changes caused by this, and on all
trials they presented slightly better (but overall insignifcant)
improvements.  This is just mentioned to assert that there are
no performance downsides to this change.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

The changes in this commit are causing intermittent failures in our CI
environment under Python 3.x.

This reverts commit 55f420f7.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

This commit makes sure all inputs in yaml2mux plugin are decoded and
passed as unicodes to variants. As a consequence this allows to actually
use this plugin on python3 environment.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

For computers this does not really matters, but for people the use of
'\n' make debugging slightly easier.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

This replaces the naive "str()" approach of turning objects into strings
with proper "astring.to_text" alternative that should take care of the
proper encoding and works well on py2 as well as py3.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

This change enables loads of pylint checks that do not require big code
changes.
Signed-off-by: NCaio Carrara <ccarrara@redhat.com>

The following two issues come up on the CI environment:

    ************* Module avocado_runner_remote
    W0622: 51,0: ConnectionError: Redefining built-in 'ConnectionError'
    ************* Module tests.test_mux
    W0622:130,8: TestMuxTree.test_basic_functions: Redefining built-in 'ascii'

And are fixed here.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

These warnings are described as:

 W0612: Used when a variable is defined but not used.
 W0622: Used when a variable or function override a built-in.

After a suggestion from Andrei Stepanov, we decided to immediately
enable these.

Rerefence: https://pagure.io/standard-test-roles/pull-request/144
Reference: https://trello.com/c/Ohh7Q6qj/1183-enable-w-in-travis-make-checkSigned-off-by: NCleber Rosa <crosa@redhat.com>

In Python 3, the order of a dictionary items will be different than
under Python 2.  To not have to change the supporting code to return
OrderedDicts, let's just simplify the comparison, breaking them down
into each dictionary item.

This fixes the varianter_yaml_to_mux plugin unittest failure under
Python 3:

    ======================================================================
    FAIL: test_fingerprint_order (tests.test_mux.TestMuxTree)
    ----------------------------------------------------------------------
    Traceback (most recent call last):
      File "/home/cleber/src/avocado/avocado/optional_plugins/varianter_yaml_to_mux/tests/test_mux.py", line 231, in test_fingerprint_order
        self.assertEqual(str(variant1), "{'paths': '', 'variant': "
    AssertionError: "{'variant_id': 'child1-child2-9154', 'varia[65 chars] ''}" != "{'paths': '', 'variant': [TreeNode(name='ch[65 chars]54'}"
    - {'variant_id': 'child1-child2-9154', 'variant': [TreeNode(name='child1'), TreeNode(name='child2')], 'paths': ''}
    + {'paths': '', 'variant': [TreeNode(name='child1'), TreeNode(name='child2')], 'variant_id': 'child1-child2-9154'}
Signed-off-by: NCleber Rosa <crosa@redhat.com>

The current code style creates and appends an object into the list,
and then later implicitly references that item using the `[-1]`
notation, changing its filter.

While correct, IMO, it's easier to follow code that creates the
object, sets its values, and then appends it to the list.

This was a style only change that appeared while debugging another
mux related issue.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

And not bytes.  What happens here is that
`avocado.core.tree.tree_view()` will return either bytes with 'utf-8'
or 'ascii' depending on the given parameter.

On Python 2, it's fine to compare the result with strings.  On Python
3, we have to get a string from the bytes returned, that is, we need
to decode the bytes.

While at it, let's fix a typo (s/asci/ascii).
Signed-off-by: NCleber Rosa <crosa@redhat.com>

Because it doesn't provide an items() method, on which six.iteritems
relies when running on Python 3.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

Which adds the namespace of the function that created the class.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

These classes and methods have knowledge about the YAML files, and the
YAML to Mux plugin is the only user of those.  this plugin.  So it
makes sense to move it to the plugin module.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

And drop the notion of a "multiplex capable" Avocado.  If the plugin is
installed, then we assume the dependencies have been fulfilled.  The plugin
presence is used then for the creation of the test suite, including the
plugin's own tests.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

This drops the notion of a "multiplex capable" Avocado.  If the plugin
is installed, then we assume the dependencies have been fulfilled.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

The AvocadoParams, as a database of test parameters, has no need
to know information about the test.  In fact, the test id parameter
has never had any real use so far.

Let's remove it.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

A lot of the core Avocado code still refers to "mux" based terminology.
For instance, what was previously "mux_path" is now "parameter paths",
and what was previously "mux" is now really variants.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

The default parameters mechanism proved to be confusing, overlapping
and thus was scheduled to be removed.  This implements the removal
of the default_params API.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

Our goal to completely separate the basic parameter interface and the
varianter pass through here: splitting these modules into their
reespective ones.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

There was once an idea that the "mux" would be an interface that would
be reused by other implementations (say, json_to_mux, foo_to_mux,
etc).  Now, it seems much more important to make the Avocado varianter
design and interfaces better, and advocate its use instead.

Additionally, there has always been a gray line between the
Multiplexer and the Avocado params.  Moving the mux outside of the
Avocado core will help to draw clearer lines.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

Instead of the iterator next method.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

This changes uses the six compatibility equivalents for iterkeys,
iteritems and itervalues.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

Don't create nodes directly, but first attempt to use OrderedDict. If
advanced features (tags, ...) are detected, declare the current mapping
TreeNode and follow as before. In the end create mapping which should
turn the directly connected OrderedDicts into TreeNodes while keep the
hidden user dicts as OrderedDicts.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

The basedir was mainly set correctly, but sometimes not used in some of
the tests. Let's move the `os.chdir` to `setUp` phase where it makes
sense and add new ones where they were not present.

Related to basedir the test_mux was using hardcoded path based on the
method used to execute the test, let's change it to `__file__` which
gives better results.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

The examples/mux-* yaml files are intended for use in selftests, but
they lived for a long time directly in examples. Let's move them to
proper place to avoid unnecessary confusion to newcomers.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

Currently the yaml_to_mux plugin is a core plugin without properly
defined requirements. Let's separate it to optional_plugins, define
dependencies and also build it separately in RPM.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

Use the combination of path-ordered leaves names and a hash of combined
fingerprint as variant_id. This should improve human-readability of the
results and also it should produce machine-friendly unique names, which
change when values in variant are modified.

Because the leaves names are ordered by path, the order of yaml file
does not affect the variant_id. On the other hand any modified/added
value changes the fingerprint and therefor variant_id.

Important feature is also that the variant still contains the
default_params, but the variant-id is not affected by it.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

The TreeNode.fingerprint() generates string, which represents the value
of the node. The idea is to represent the content of the node and it's
environment and such for the purpose of evaluating, whether other node
is alike.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

This adds the support to define per-node filters, which take part of
environment and are evaluated during multiplexation.

The basic idea is to define relations ({could be only used | could
not be used} with other branch), which makes it a bit different from
what we know from `--mux-filter-{only|out}`:

1. They are applied per complete variant (because the filters are
   compound of per-leaf-filters)
2. They don't remove/keep the nodes, but they only evaluate whether
   this resulting variant makes sense (whether it passes the filters)

See the updated documentation for details.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

This patch replaces the hardcoded mux in Varianter for list of Varianter
plugins, iterating through all of them to produce all specified
variants. The interface is described in `avocado.core.plugin_interfaces`
and we also provide base-implementation for Mux-like plugins in
`avocado.core.mux`.

Mainly this PR is about defining the stevedore entry points, moving the
code around and wrapping the code into a class according the defined
stevedore interface. Doing so allowed us to simplify the `MuxTree`
object which does not need to keep track of the `root` of the tree,
because the root is stored in the pluggin's instance.

There is still one potential issue in Varianter which is probably even
more visible now, which is that we are pickling it in jobdata in order
to be able to reproduce the variants when re-running/diffing the job.
Before this was prone to code-changes but now it can be even worse as
multiple plugins can be enabled and can break loading of the previous
state. To avoid the potential breakage this version simply initializes
only the available extensions which should produce only the supported
variants.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

Previously we were directly using the yaml.Loader, which is shared
across all `yaml` instances. This patch creates a `_BaseLoader` with the
basic set of constructors. That one is copied and updated of the
run-time data (debug/non-debug) during the `_create_from_yaml` to allow
loading debug and non-debug files in a single execution without
overriding the same loader.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

The unittest standard library on Python 2.7 an later has everything
that the unittest2 backport is supposed to have.  Let's then drop all
the conditional imports of unittest2 and stick with unittest.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

The filtering is not useful for basic params, let's move it to mux and
while on it also remove the avocado arguments (options) to the
yaml_to_mux plugin.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

The `avocado.core.tree` contains multiplex/mux-related features like
multiplex and ctrl, which are not really useful for basic params. Let's
simplify the base tree object and put the extracted features in
`avocado.core.mux`.

This is a first step and the `avocado.core.mux` should contain most of
the generic parts useful for creating varianter plugins.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

The concept of multiplexer is about to be split into an abstract API for
variants generation, multiplexer which will be in-core implementation of
one of the variants generation plugins and yaml_to_mux plugin which uses
this multiplexer implementation to create variants from a yaml file.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>