# Copyright 2020 Timothy M. Shead
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Functionality for testing preconditions and assertions.
"""
import functools
import sys
[docs]def loaded_module(modules):
"""Function decorator that tests whether module(s) have already been loaded.
Parameters
----------
modules: :class:`str` or sequence of :class:`str`, required
Names of the modules that must already be loaded for the wrapped
function to execute.
Raises
------
:class:`RuntimeError`
If any module in `modules` isn't already loaded.
"""
if isinstance(modules, str):
modules = (modules,)
def implementation(f):
@functools.wraps(f)
def implementation(*args, **kwargs):
for module in modules:
if module not in sys.modules:
raise RuntimeError(f"Module {module} could not be found.")
return f(*args, **kwargs)
return implementation
return implementation