"""
Bootstrapper for nose/pytest plugins.

The entire rationale for this system is to get the modules in plugin/
imported without importing all of the supporting library, so that we can
set up things for testing before coverage starts.

The rationale for all of plugin/ being *in* the supporting library in the
first place is so that the testing and plugin suite is available to other
libraries, mainly external SQLAlchemy and Alembic dialects, to make use
of the same test environment and standard suites available to
SQLAlchemy/Alembic themselves without the need to ship/install a separate
package outside of SQLAlchemy.

NOTE:  copied/adapted from SQLAlchemy master for backwards compatibility;
this should be removable when Alembic targets SQLAlchemy 1.0.0.

"""

import os
import sys

bootstrap_file = locals()['bootstrap_file']
to_bootstrap = locals()['to_bootstrap']


def load_file_as_module(name):
    path = os.path.join(os.path.dirname(bootstrap_file), "%s.py" % name)
    if sys.version_info >= (3, 3):
        from importlib import machinery
        mod = machinery.SourceFileLoader(name, path).load_module()
    else:
        import imp
        mod = imp.load_source(name, path)
    return mod

if to_bootstrap == "pytest":
    sys.modules["alembic_plugin_base"] = load_file_as_module("plugin_base")
    sys.modules["alembic_pytestplugin"] = load_file_as_module("pytestplugin")
elif to_bootstrap == "nose":
    sys.modules["alembic_plugin_base"] = load_file_as_module("plugin_base")
    sys.modules["alembic_noseplugin"] = load_file_as_module("noseplugin")
else:
    raise Exception("unknown bootstrap: %s" % to_bootstrap)  # noqa