api/faux.py

# Copyright 2019 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Decorators to help handle mock calls and errors in the Build API."""

import functools

from chromite.api import controller


def all_responses(faux_result_factory):
    """A decorator to handle all mock responses.

    This is syntactic sugar for handling all the mock response types in a
    single function.

    Args:
        faux_result_factory: A function with the same signature as a regular
            API endpoint function that populates the output with success or
            error results, as requested, without executing the endpoint.
    """
    assert faux_result_factory

    # Get the decorators for each of the mock types, so we can compose them.
    success_fn = success(faux_result_factory)
    err_fn = error(faux_result_factory)

    def _decorator(func):
        return err_fn(success_fn(func))

    return _decorator


def all_empty(func):
    """Decorator to handle all mock responses with an empty output."""
    return empty_error(empty_success(func))


def success(faux_result_factory):
    """A decorator to handle mock call responses.

    Args:
        faux_result_factory: A function with the same signature as a regular
            API endpoint function that populates the output
    """
    assert faux_result_factory

    def decorator(func):
        @functools.wraps(func)
        def _success(input_proto, output_proto, config, *args, **kwargs):
            if config.mock_call:
                faux_result_factory(
                    input_proto, output_proto, config, *args, **kwargs
                )
                return controller.RETURN_CODE_SUCCESS

            return func(input_proto, output_proto, config, *args, **kwargs)

        return _success

    return decorator


def empty_success(func):
    """A decorator to handle mock success responses with empty outputs."""

    @functools.wraps(func)
    def _empty_success(input_proto, output_proto, config, *args, **kwargs):
        if config.mock_call:
            return controller.RETURN_CODE_SUCCESS

        return func(input_proto, output_proto, config, *args, **kwargs)

    return _empty_success


def error(faux_error_factory):
    """A decorator to handle mock error responses."""
    assert faux_error_factory

    def decorator(func):
        @functools.wraps(func)
        def _error(input_proto, output_proto, config, *args, **kwargs):
            if config.mock_error:
                faux_error_factory(
                    input_proto, output_proto, config, *args, **kwargs
                )
                return controller.RETURN_CODE_UNSUCCESSFUL_RESPONSE_AVAILABLE

            return func(input_proto, output_proto, config, *args, **kwargs)

        return _error

    return decorator


def empty_error(func):
    """A decorator to handle mock error responses with empty outputs."""

    @functools.wraps(func)
    def _empty_error(input_proto, output_proto, config, *args, **kwargs):
        if config.mock_error:
            return controller.RETURN_CODE_UNRECOVERABLE

        return func(input_proto, output_proto, config, *args, **kwargs)

    return _empty_error


def empty_completed_unsuccessfully_error(func):
    """A decorator to handle mock unsuccessful response with empty outputs."""

    @functools.wraps(func)
    def _empty_error(input_proto, output_proto, config, *args, **kwargs):
        if config.mock_error:
            return controller.RETURN_CODE_COMPLETED_UNSUCCESSFULLY

        return func(input_proto, output_proto, config, *args, **kwargs)

    return _empty_error