@@ -32,7 +32,7 @@ from molecule import logger
 from molecule import util
 
 LOG = logger.get_logger(__name__)
-MOLECULE_GLOB = 'molecule/*/molecule.yml'
+MOLECULE_GLOB = os.environ.get('MOLECULE_GLOB', 'molecule/*/molecule.yml')
 MOLECULE_DEFAULT_SCENARIO_NAME = 'default'
 
 
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#  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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#  DEALINGS IN THE SOFTWARE.

import abc
import collections
import fnmatch
import glob
import os

import six

import molecule.command
from molecule import config
from molecule import logger
from molecule import util

LOG = logger.get_logger(__name__)
MOLECULE_GLOB = 'molecule/*/molecule.yml'
MOLECULE_DEFAULT_SCENARIO_NAME = 'default'


@six.add_metaclass(abc.ABCMeta)
class Base(object):
    """
    An abstract base class used to define the command interface.
    """

    def __init__(self, c):
        """
        Base initializer for all :ref:`Command` classes.

        :param c: An instance of a Molecule config.
        :returns: None
        """
        self._config = c
        self._setup()

    @abc.abstractmethod
    def execute(self):  # pragma: no cover
        pass

    def prune(self):
        """
        Prune the ephemeral directory with the exception of safe files and
        returns None.

        :return: None
        """
        safe_files = [
            self._config.provisioner.config_file,
            self._config.provisioner.inventory_file,
            self._config.state.state_file,
        ] + self._config.driver.safe_files
        files = util.os_walk(self._config.scenario.ephemeral_directory, '*')
        for f in files:
            if not any(sf for sf in safe_files if fnmatch.fnmatch(f, sf)):
                os.remove(f)

        # Remove empty directories.
        for dirpath, dirs, files in os.walk(
                self._config.scenario.ephemeral_directory, topdown=False):
            if not dirs and not files:
                os.removedirs(dirpath)

    def print_info(self):
        msg = "Scenario: '{}'".format(self._config.scenario.name)
        LOG.info(msg)
        msg = "Action: '{}'".format(util.underscore(self.__class__.__name__))
        LOG.info(msg)

    def _setup(self):
        """
        Prepare Molecule's provisioner and returns None.

        :return: None
        """
        self._config.provisioner.write_config()
        self._config.provisioner.manage_inventory()


def execute_subcommand(config, subcommand):
    command_module = getattr(molecule.command, subcommand)
    command = getattr(command_module, util.camelize(subcommand))

    return command(config).execute()


def get_configs(args, command_args, ansible_args=()):
    """
    Glob the current directory for Molecule config files, instantiate config
    objects, and returns a list.

    :param args: A dict of options, arguments and commands from the CLI.
    :param command_args: A dict of options passed to the subcommand from
     the CLI.
    :param ansible_args: An optional tuple of arguments provided to the
     `ansible-playbook` command.
    :return: list
    """
    configs = [
        config.Config(
            molecule_file=util.abs_path(c),
            args=args,
            command_args=command_args,
            ansible_args=ansible_args,
        ) for c in glob.glob(MOLECULE_GLOB)
    ]
    _verify_configs(configs)

    return configs


def _verify_configs(configs):
    """
    Verify a Molecule config was found and returns None.

    :param configs: A list containing absolute paths to Molecule config files.
    :return: None
    """
    if configs:
        scenario_names = [c.scenario.name for c in configs]
        for scenario_name, n in collections.Counter(scenario_names).items():
            if n > 1:
                msg = ("Duplicate scenario name '{}' found.  "
                       'Exiting.').format(scenario_name)
                util.sysexit_with_message(msg)

    else:
        msg = "'{}' glob failed.  Exiting.".format(MOLECULE_GLOB)
        util.sysexit_with_message(msg)


def _get_subcommand(string):
    return string.split('.')[-1]

Do we also need to register this in `molecule/config.py`? Can we also get a test for it?