flask/tests/conftest.py

# -*- coding: utf-8 -*-
"""
    tests.conftest
    ~~~~~~~~~~~~~~

    :copyright: © 2010 by the Pallets team.
    :license: BSD, see LICENSE for more details.
"""

import gc
import os
import pkgutil
import sys
import textwrap

import pytest
from _pytest import monkeypatch

import flask
from flask import Flask as _Flask


@pytest.fixture(scope='session', autouse=True)
def _standard_os_environ():
    """Set up ``os.environ`` at the start of the test session to have
    standard values. Returns a list of operations that is used by
    :func:`._reset_os_environ` after each test.
    """
    mp = monkeypatch.MonkeyPatch()
    out = (
        (os.environ, 'FLASK_APP', monkeypatch.notset),
        (os.environ, 'FLASK_ENV', monkeypatch.notset),
        (os.environ, 'FLASK_DEBUG', monkeypatch.notset),
        (os.environ, 'FLASK_RUN_FROM_CLI', monkeypatch.notset),
        (os.environ, 'WERKZEUG_RUN_MAIN', monkeypatch.notset),
    )

    for _, key, value in out:
        if value is monkeypatch.notset:
            mp.delenv(key, False)
        else:
            mp.setenv(key, value)

    yield out
    mp.undo()


@pytest.fixture(autouse=True)
def _reset_os_environ(monkeypatch, _standard_os_environ):
    """Reset ``os.environ`` to the standard environ after each test,
    in case a test changed something without cleaning up.
    """
    monkeypatch._setitem.extend(_standard_os_environ)


class Flask(_Flask):
    testing = True
    secret_key = 'test key'


@pytest.fixture
def app():
    app = Flask('flask_test', root_path=os.path.dirname(__file__))
    return app


@pytest.fixture
def app_ctx(app):
    with app.app_context() as ctx:
        yield ctx


@pytest.fixture
def req_ctx(app):
    with app.test_request_context() as ctx:
        yield ctx


@pytest.fixture
def client(app):
    return app.test_client()


@pytest.fixture
def test_apps(monkeypatch):
    monkeypatch.syspath_prepend(
        os.path.abspath(os.path.join(
            os.path.dirname(__file__), 'test_apps'))
    )


@pytest.fixture(autouse=True)
def leak_detector():
    yield

    # make sure we're not leaking a request context since we are
    # testing flask internally in debug mode in a few cases
    leaks = []
    while flask._request_ctx_stack.top is not None:
        leaks.append(flask._request_ctx_stack.pop())
    assert leaks == []


@pytest.fixture(params=(True, False))
def limit_loader(request, monkeypatch):
    """Patch pkgutil.get_loader to give loader without get_filename or archive.

    This provides for tests where a system has custom loaders, e.g. Google App
    Engine's HardenedModulesHook, which have neither the `get_filename` method
    nor the `archive` attribute.

    This fixture will run the testcase twice, once with and once without the
    limitation/mock.
    """
    if not request.param:
        return

    class LimitedLoader(object):
        def __init__(self, loader):
            self.loader = loader

        def __getattr__(self, name):
            if name in ('archive', 'get_filename'):
                msg = 'Mocking a loader which does not have `%s.`' % name
                raise AttributeError(msg)
            return getattr(self.loader, name)

    old_get_loader = pkgutil.get_loader

    def get_loader(*args, **kwargs):
        return LimitedLoader(old_get_loader(*args, **kwargs))

    monkeypatch.setattr(pkgutil, 'get_loader', get_loader)


@pytest.fixture
def modules_tmpdir(tmpdir, monkeypatch):
    """A tmpdir added to sys.path."""
    rv = tmpdir.mkdir('modules_tmpdir')
    monkeypatch.syspath_prepend(str(rv))
    return rv


@pytest.fixture
def modules_tmpdir_prefix(modules_tmpdir, monkeypatch):
    monkeypatch.setattr(sys, 'prefix', str(modules_tmpdir))
    return modules_tmpdir


@pytest.fixture
def site_packages(modules_tmpdir, monkeypatch):
    """Create a fake site-packages."""
    rv = modules_tmpdir \
        .mkdir('lib') \
        .mkdir('python{x[0]}.{x[1]}'.format(x=sys.version_info)) \
        .mkdir('site-packages')
    monkeypatch.syspath_prepend(str(rv))
    return rv


@pytest.fixture
def install_egg(modules_tmpdir, monkeypatch):
    """Generate egg from package name inside base and put the egg into
    sys.path."""

    def inner(name, base=modules_tmpdir):
        if not isinstance(name, str):
            raise ValueError(name)
        base.join(name).ensure_dir()
        base.join(name).join('__init__.py').ensure()

        egg_setup = base.join('setup.py')
        egg_setup.write(textwrap.dedent("""
        from setuptools import setup
        setup(name='{0}',
              version='1.0',
              packages=['site_egg'],
              zip_safe=True)
        """.format(name)))

        import subprocess
        subprocess.check_call(
            [sys.executable, 'setup.py', 'bdist_egg'],
            cwd=str(modules_tmpdir)
        )
        egg_path, = modules_tmpdir.join('dist/').listdir()
        monkeypatch.syspath_prepend(str(egg_path))
        return egg_path

    return inner


@pytest.fixture
def purge_module(request):
    def inner(name):
        request.addfinalizer(lambda: sys.modules.pop(name, None))

    return inner