# Source code for tornado.testing

    #!/usr/bin/env python
    """Support classes for automated testing.

    * `AsyncTestCase` and `AsyncHTTPTestCase`:  Subclasses of unittest.TestCase
      with additional support for testing asynchronous (`.IOLoop`-based) code.

    * `ExpectLog` and `LogTrapTestCase`: Make test logs less spammy.

    * `main()`: A simple test runner (wrapper around unittest.main()) with support
      for the tornado4.autoreload module to rerun the tests when code changes.
    """

    from __future__ import absolute_import, division, print_function

    try:
        from tornado4 import gen
        from tornado4.httpclient import AsyncHTTPClient
        from tornado4.httpserver import HTTPServer
        from tornado4.simple_httpclient import SimpleAsyncHTTPClient
        from tornado4.ioloop import IOLoop, TimeoutError
        from tornado4 import netutil
        from tornado4.process import Subprocess
    except ImportError:
        # These modules are not importable on app engine.  Parts of this module
        # won't work, but e.g. LogTrapTestCase and main() will.
        AsyncHTTPClient = None  # type: ignore
        gen = None  # type: ignore
        HTTPServer = None  # type: ignore
        IOLoop = None  # type: ignore
        netutil = None  # type: ignore
        SimpleAsyncHTTPClient = None  # type: ignore
        Subprocess = None  # type: ignore
    from tornado4.log import gen_log, app_log
    from tornado4.stack_context import ExceptionStackContext
    from tornado4.util import raise_exc_info, basestring_type, PY3
    import functools
    import inspect
    import logging
    import os
    import re
    import signal
    import socket
    import sys

    if PY3:
        from io import StringIO
    else:
        from cStringIO import StringIO

    try:
        from collections.abc import Generator as GeneratorType  # type: ignore
    except ImportError:
        from types import GeneratorType  # type: ignore

    if sys.version_info >= (3, 5):
        iscoroutine = inspect.iscoroutine  # type: ignore
        iscoroutinefunction = inspect.iscoroutinefunction  # type: ignore
    else:
        iscoroutine = iscoroutinefunction = lambda f: False

    # Tornado's own test suite requires the updated unittest module
    # (either py27+ or unittest2) so tornado4.test.util enforces
    # this requirement, but for other users of tornado4.testing we want
    # to allow the older version if unitest2 is not available.
    if PY3:
        # On python 3, mixing unittest2 and unittest (including doctest)
        # doesn't seem to work, so always use unittest.
        import unittest
    else:
        # On python 2, prefer unittest2 when available.
        try:
            import unittest2 as unittest  # type: ignore
        except ImportError:
            import unittest  # type: ignore

    _next_port = 10000

    def get_unused_port():
        """Returns a (hopefully) unused port number.

        This function does not guarantee that the port it returns is available,
        only that a series of get_unused_port calls in a single process return
        distinct ports.

        .. deprecated::
           Use bind_unused_port instead, which is guaranteed to find an unused port.
        """
        global _next_port
        port = _next_port
        _next_port = _next_port + 1
        return port

    def bind_unused_port(reuse_port=False):
        """Binds a server socket to an available port on localhost.

        Returns a tuple (socket, port).

        .. versionchanged:: 4.4
           Always binds to ``127.0.0.1`` without resolving the name
           ``localhost``.
        """
        sock = netutil.bind_sockets(None, '127.0.0.1', family=socket.AF_INET,
                                    reuse_port=reuse_port)[0]
        port = sock.getsockname()[1]
        return sock, port

    def get_async_test_timeout():
        """Get the global timeout setting for async tests.

        Returns a float, the timeout in seconds.

        .. versionadded:: 3.1
        """
        try:
            return float(os.environ.get('ASYNC_TEST_TIMEOUT'))
        except (ValueError, TypeError):
            return 5

    class _TestMethodWrapper(object):
        """Wraps a test method to raise an error if it returns a value.

        This is mainly used to detect undecorated generators (if a test
        method yields it must use a decorator to consume the generator),
        but will also detect other kinds of return values (these are not
        necessarily errors, but we alert anyway since there is no good
        reason to return a value from a test).
        """
        def __init__(self, orig_method):
            self.orig_method = orig_method

        def __call__(self, *args, **kwargs):
            result = self.orig_method(*args, **kwargs)
            if isinstance(result, GeneratorType) or iscoroutine(result):
                raise TypeError("Generator and coroutine test methods should be"
                                " decorated with tornado4.testing.gen_test")
            elif result is not None:
                raise ValueError("Return value from test method ignored: %r" %
                                 result)

        def __getattr__(self, name):
            """Proxy all unknown attributes to the original method.

            This is important for some of the decorators in the `unittest`
            module, such as `unittest.skipIf`.
            """
            return getattr(self.orig_method, name)

    class AsyncTestCase(unittest.TestCase):
        """`~unittest.TestCase` subclass for testing `.IOLoop`-based
        asynchronous code.

        The unittest framework is synchronous, so the test must be
        complete by the time the test method returns.  This means that
        asynchronous code cannot be used in quite the same way as usual.
        To write test functions that use the same ``yield``-based patterns
        used with the `tornado4.gen` module, decorate your test methods
        with `tornado4.testing.gen_test` instead of
        `tornado4.gen.coroutine`.  This class also provides the `stop()`
        and `wait()` methods for a more manual style of testing.  The test
        method itself must call ``self.wait()``, and asynchronous
        callbacks should call ``self.stop()`` to signal completion.

        By default, a new `.IOLoop` is constructed for each test and is available
        as ``self.io_loop``.  This `.IOLoop` should be used in the construction of
        HTTP clients/servers, etc.  If the code being tested requires a
        global `.IOLoop`, subclasses should override `get_new_ioloop` to return it.

        The `.IOLoop`'s ``start`` and ``stop`` methods should not be
        called directly.  Instead, use `self.stop <stop>` and `self.wait
        <wait>`.  Arguments passed to ``self.stop`` are returned from
        ``self.wait``.  It is possible to have multiple ``wait``/``stop``
        cycles in the same test.

        Example::

            # This test uses coroutine style.
            class MyTestCase(AsyncTestCase):
                @tornado4.testing.gen_test
                def test_http_fetch(self):
                    client = AsyncHTTPClient(self.io_loop)
                    response = yield client.fetch("http://www.tornadoweb.org")
                    # Test contents of response
                    self.assertIn("FriendFeed", response.body)

            # This test uses argument passing between self.stop and self.wait.
            class MyTestCase2(AsyncTestCase):
                def test_http_fetch(self):
                    client = AsyncHTTPClient(self.io_loop)
                    client.fetch("http://www.tornadoweb.org/", self.stop)
                    response = self.wait()
                    # Test contents of response
                    self.assertIn("FriendFeed", response.body)

            # This test uses an explicit callback-based style.
            class MyTestCase3(AsyncTestCase):
                def test_http_fetch(self):
                    client = AsyncHTTPClient(self.io_loop)
                    client.fetch("http://www.tornadoweb.org/", self.handle_fetch)
                    self.wait()

                def handle_fetch(self, response):
                    # Test contents of response (failures and exceptions here
                    # will cause self.wait() to throw an exception and end the
                    # test).
                    # Exceptions thrown here are magically propagated to
                    # self.wait() in test_http_fetch() via stack_context.
                    self.assertIn("FriendFeed", response.body)
                    self.stop()
        """
        def __init__(self, methodName='runTest'):
            super(AsyncTestCase, self).__init__(methodName)
            self.__stopped = False
            self.__running = False
            self.__failure = None
            self.__stop_args = None
            self.__timeout = None

            # It's easy to forget the @gen_test decorator, but if you do
            # the test will silently be ignored because nothing will consume
            # the generator.  Replace the test method with a wrapper that will
            # make sure it's not an undecorated generator.
            setattr(self, methodName, _TestMethodWrapper(getattr(self, methodName)))

        def setUp(self):
            super(AsyncTestCase, self).setUp()
            self.io_loop = self.get_new_ioloop()
            self.io_loop.make_current()

        def tearDown(self):
            # Clean up Subprocess, so it can be used again with a new ioloop.
            Subprocess.uninitialize()
            self.io_loop.clear_current()
            if (not IOLoop.initialized() or
                    self.io_loop is not IOLoop.instance()):
                # Try to clean up any file descriptors left open in the ioloop.
                # This avoids leaks, especially when tests are run repeatedly
                # in the same process with autoreload (because curl does not
                # set FD_CLOEXEC on its file descriptors)
                self.io_loop.close(all_fds=True)
            super(AsyncTestCase, self).tearDown()
            # In case an exception escaped or the StackContext caught an exception
            # when there wasn't a wait() to re-raise it, do so here.
            # This is our last chance to raise an exception in a way that the
            # unittest machinery understands.
            self.__rethrow()

        def get_new_ioloop(self):
            """Creates a new `.IOLoop` for this test.  May be overridden in
            subclasses for tests that require a specific `.IOLoop` (usually
            the singleton `.IOLoop.instance()`).
            """
            return IOLoop()

        def _handle_exception(self, typ, value, tb):
            if self.__failure is None:
                self.__failure = (typ, value, tb)
            else:
                app_log.error("multiple unhandled exceptions in test",
                              exc_info=(typ, value, tb))
            self.stop()
            return True

        def __rethrow(self):
            if self.__failure is not None:
                failure = self.__failure
                self.__failure = None
                raise_exc_info(failure)

        def run(self, result=None):
            with ExceptionStackContext(self._handle_exception):
                super(AsyncTestCase, self).run(result)
            # As a last resort, if an exception escaped super.run() and wasn't
            # re-raised in tearDown, raise it here.  This will cause the
            # unittest run to fail messily, but that's better than silently
            # ignoring an error.
            self.__rethrow()

        def stop(self, _arg=None, **kwargs):
            """Stops the `.IOLoop`, causing one pending (or future) call to `wait()`
            to return.

            Keyword arguments or a single positional argument passed to `stop()` are
            saved and will be returned by `wait()`.
            """
            assert _arg is None or not kwargs
            self.__stop_args = kwargs or _arg
            if self.__running:
                self.io_loop.stop()
                self.__running = False
            self.__stopped = True

        def wait(self, condition=None, timeout=None):
            """Runs the `.IOLoop` until stop is called or timeout has passed.

            In the event of a timeout, an exception will be thrown. The
            default timeout is 5 seconds; it may be overridden with a
            ``timeout`` keyword argument or globally with the
            ``ASYNC_TEST_TIMEOUT`` environment variable.

            If ``condition`` is not None, the `.IOLoop` will be restarted
            after `stop()` until ``condition()`` returns true.

            .. versionchanged:: 3.1
               Added the ``ASYNC_TEST_TIMEOUT`` environment variable.
            """
            if timeout is None:
                timeout = get_async_test_timeout()

            if not self.__stopped:
                if timeout:
                    def timeout_func():
                        try:
                            raise self.failureException(
                                'Async operation timed out after %s seconds' %
                                timeout)
                        except Exception:
                            self.__failure = sys.exc_info()
                        self.stop()
                    self.__timeout = self.io_loop.add_timeout(self.io_loop.time() + timeout, timeout_func)
                while True:
                    self.__running = True
                    self.io_loop.start()
                    if (self.__failure is not None or
                            condition is None or condition()):
                        break
                if self.__timeout is not None:
                    self.io_loop.remove_timeout(self.__timeout)
                    self.__timeout = None
            assert self.__stopped
            self.__stopped = False
            self.__rethrow()
            result = self.__stop_args
            self.__stop_args = None
            return result

    class AsyncHTTPTestCase(AsyncTestCase):
        """A test case that starts up an HTTP server.

        Subclasses must override `get_app()`, which returns the
        `tornado4.web.Application` (or other `.HTTPServer` callback) to be tested.
        Tests will typically use the provided ``self.http_client`` to fetch
        URLs from this server.

        Example, assuming the "Hello, world" example from the user guide is in
        ``hello.py``::

            import hello

            class TestHelloApp(AsyncHTTPTestCase):
                def get_app(self):
                    return hello.make_app()

                def test_homepage(self):
                    response = self.fetch('/')
                    self.assertEqual(response.code, 200)
                    self.assertEqual(response.body, 'Hello, world')

        That call to ``self.fetch()`` is equivalent to ::

            self.http_client.fetch(self.get_url('/'), self.stop)
            response = self.wait()

        which illustrates how AsyncTestCase can turn an asynchronous operation,
        like ``http_client.fetch()``, into a synchronous operation. If you need
        to do other asynchronous operations in tests, you'll probably need to use
        ``stop()`` and ``wait()`` yourself.
        """
        def setUp(self):
            super(AsyncHTTPTestCase, self).setUp()
            sock, port = bind_unused_port()
            self.__port = port

            self.http_client = self.get_http_client()
            self._app = self.get_app()
            self.http_server = self.get_http_server()
            self.http_server.add_sockets([sock])

        def get_http_client(self):
            return AsyncHTTPClient(io_loop=self.io_loop)

        def get_http_server(self):
            return HTTPServer(self._app, io_loop=self.io_loop,
                              **self.get_httpserver_options())

        def get_app(self):
            """Should be overridden by subclasses to return a
            `tornado4.web.Application` or other `.HTTPServer` callback.
            """
            raise NotImplementedError()

        def fetch(self, path, **kwargs):
            """Convenience method to synchronously fetch a url.

            The given path will be appended to the local server's host and
            port.  Any additional kwargs will be passed directly to
            `.AsyncHTTPClient.fetch` (and so could be used to pass
            ``method="POST"``, ``body="..."``, etc).
            """
            self.http_client.fetch(self.get_url(path), self.stop, **kwargs)
            return self.wait()

        def get_httpserver_options(self):
            """May be overridden by subclasses to return additional
            keyword arguments for the server.
            """
            return {}

        def get_http_port(self):
            """Returns the port used by the server.

            A new port is chosen for each test.
            """
            return self.__port

        def get_protocol(self):
            return 'http'

        def get_url(self, path):
            """Returns an absolute url for the given path on the test server."""
            return '%s://127.0.0.1:%s%s' % (self.get_protocol(),
                                            self.get_http_port(), path)

        def tearDown(self):
            self.http_server.stop()
            self.io_loop.run_sync(self.http_server.close_all_connections,
                                  timeout=get_async_test_timeout())
            if (not IOLoop.initialized() or
                    self.http_client.io_loop is not IOLoop.instance()):
                self.http_client.close()
            super(AsyncHTTPTestCase, self).tearDown()

    class AsyncHTTPSTestCase(AsyncHTTPTestCase):
        """A test case that starts an HTTPS server.

        Interface is generally the same as `AsyncHTTPTestCase`.
        """
        def get_http_client(self):
            return AsyncHTTPClient(io_loop=self.io_loop, force_instance=True,
                                   defaults=dict(validate_cert=False))

        def get_httpserver_options(self):
            return dict(ssl_options=self.get_ssl_options())

        def get_ssl_options(self):
            """May be overridden by subclasses to select SSL options.

            By default includes a self-signed testing certificate.
            """
            # Testing keys were generated with:
            # openssl req -new -keyout tornado/test/test.key -out tornado/test/test.crt -nodes -days 3650 -x509
            module_dir = os.path.dirname(__file__)
            return dict(
                certfile=os.path.join(module_dir, 'test', 'test.crt'),
                keyfile=os.path.join(module_dir, 'test', 'test.key'))

        def get_protocol(self):
            return 'https'

    def gen_test(func=None, timeout=None):
        """Testing equivalent of ``@gen.coroutine``, to be applied to test methods.

        ``@gen.coroutine`` cannot be used on tests because the `.IOLoop` is not
        already running.  ``@gen_test`` should be applied to test methods
        on subclasses of `AsyncTestCase`.

        Example::

            class MyTest(AsyncHTTPTestCase):
                @gen_test
                def test_something(self):
                    response = yield gen.Task(self.fetch('/'))

        By default, ``@gen_test`` times out after 5 seconds. The timeout may be
        overridden globally with the ``ASYNC_TEST_TIMEOUT`` environment variable,
        or for each test with the ``timeout`` keyword argument::

            class MyTest(AsyncHTTPTestCase):
                @gen_test(timeout=10)
                def test_something_slow(self):
                    response = yield gen.Task(self.fetch('/'))

        .. versionadded:: 3.1
           The ``timeout`` argument and ``ASYNC_TEST_TIMEOUT`` environment
           variable.

        .. versionchanged:: 4.0
           The wrapper now passes along ``*args, **kwargs`` so it can be used
           on functions with arguments.
        """
        if timeout is None:
            timeout = get_async_test_timeout()

        def wrap(f):
            # Stack up several decorators to allow us to access the generator
            # object itself.  In the innermost wrapper, we capture the generator
            # and save it in an attribute of self.  Next, we run the wrapped
            # function through @gen.coroutine.  Finally, the coroutine is
            # wrapped again to make it synchronous with run_sync.
            #
            # This is a good case study arguing for either some sort of
            # extensibility in the gen decorators or cancellation support.
            @functools.wraps(f)
            def pre_coroutine(self, *args, **kwargs):
                result = f(self, *args, **kwargs)
                if isinstance(result, GeneratorType) or iscoroutine(result):
                    self._test_generator = result
                else:
                    self._test_generator = None
                return result

            if iscoroutinefunction(f):
                coro = pre_coroutine
            else:
                coro = gen.coroutine(pre_coroutine)

            @functools.wraps(coro)
            def post_coroutine(self, *args, **kwargs):
                try:
                    return self.io_loop.run_sync(
                        functools.partial(coro, self, *args, **kwargs),
                        timeout=timeout)
                except TimeoutError as e:
                    # run_sync raises an error with an unhelpful traceback.
                    # Throw it back into the generator or coroutine so the stack
                    # trace is replaced by the point where the test is stopped.
                    self._test_generator.throw(e)
                    # In case the test contains an overly broad except clause,
                    # we may get back here.  In this case re-raise the original
                    # exception, which is better than nothing.
                    raise
            return post_coroutine

        if func is not None:
            # Used like:
            #     @gen_test
            #     def f(self):
            #         pass
            return wrap(func)
        else:
            # Used like @gen_test(timeout=10)
            return wrap

    # Without this attribute, nosetests will try to run gen_test as a test
    # anywhere it is imported.
    gen_test.__test__ = False  # type: ignore

    class LogTrapTestCase(unittest.TestCase):
        """A test case that captures and discards all logging output
        if the test passes.

        Some libraries can produce a lot of logging output even when
        the test succeeds, so this class can be useful to minimize the noise.
        Simply use it as a base class for your test case.  It is safe to combine
        with AsyncTestCase via multiple inheritance
        (``class MyTestCase(AsyncHTTPTestCase, LogTrapTestCase):``)

        This class assumes that only one log handler is configured and
        that it is a `~logging.StreamHandler`.  This is true for both
        `logging.basicConfig` and the "pretty logging" configured by
        `tornado4.options`.  It is not compatible with other log buffering
        mechanisms, such as those provided by some test runners.

        .. deprecated:: 4.1
           Use the unittest module's ``--buffer`` option instead, or `.ExpectLog`.
        """
        def run(self, result=None):
            logger = logging.getLogger()
            if not logger.handlers:
                logging.basicConfig()
            handler = logger.handlers[0]
            if (len(logger.handlers) > 1 or
                    not isinstance(handler, logging.StreamHandler)):
                # Logging has been configured in a way we don't recognize,
                # so just leave it alone.
                super(LogTrapTestCase, self).run(result)
                return
            old_stream = handler.stream
            try:
                handler.stream = StringIO()
                gen_log.info("RUNNING TEST: " + str(self))
                old_error_count = len(result.failures) + len(result.errors)
                super(LogTrapTestCase, self).run(result)
                new_error_count = len(result.failures) + len(result.errors)
                if new_error_count != old_error_count:
                    old_stream.write(handler.stream.getvalue())
            finally:
                handler.stream = old_stream

    class ExpectLog(logging.Filter):
        """Context manager to capture and suppress expected log output.

        Useful to make tests of error conditions less noisy, while still
        leaving unexpected log entries visible.  *Not thread safe.*

        The attribute ``logged_stack`` is set to true if any exception
        stack trace was logged.

        Usage::

            with ExpectLog('tornado4.application', "Uncaught exception"):
                error_response = self.fetch("/some_page")

        .. versionchanged:: 4.3
           Added the ``logged_stack`` attribute.
        """
        def __init__(self, logger, regex, required=True):
            """Constructs an ExpectLog context manager.

            :param logger: Logger object (or name of logger) to watch.  Pass
                an empty string to watch the root logger.
            :param regex: Regular expression to match.  Any log entries on
                the specified logger that match this regex will be suppressed.
            :param required: If true, an exception will be raised if the end of
                the ``with`` statement is reached without matching any log entries.
            """
            if isinstance(logger, basestring_type):
                logger = logging.getLogger(logger)
            self.logger = logger
            self.regex = re.compile(regex)
            self.required = required
            self.matched = False
            self.logged_stack = False

        def filter(self, record):
            if record.exc_info:
                self.logged_stack = True
            message = record.getMessage()
            if self.regex.match(message):
                self.matched = True
                return False
            return True

        def __enter__(self):
            self.logger.addFilter(self)
            return self

        def __exit__(self, typ, value, tb):
            self.logger.removeFilter(self)
            if not typ and self.required and not self.matched:
                raise Exception("did not get expected log message")

    def main(**kwargs):
        """A simple test runner.

        This test runner is essentially equivalent to `unittest.main` from
        the standard library, but adds support for tornado-style option
        parsing and log formatting. It is *not* necessary to use this
        `main` function to run tests using `AsyncTestCase`; these tests
        are self-contained and can run with any test runner.

        The easiest way to run a test is via the command line::

            python -m tornado4.testing tornado4.test.stack_context_test

        See the standard library unittest module for ways in which tests can
        be specified.

        Projects with many tests may wish to define a test script like
        ``tornado/test/runtests.py``.  This script should define a method
        ``all()`` which returns a test suite and then call
        `tornado4.testing.main()`.  Note that even when a test script is
        used, the ``all()`` test suite may be overridden by naming a
        single test on the command line::

            # Runs all tests
            python -m tornado4.test.runtests
            # Runs one test
            python -m tornado4.test.runtests tornado4.test.stack_context_test

        Additional keyword arguments passed through to ``unittest.main()``.
        For example, use ``tornado4.testing.main(verbosity=2)``
        to show many test details as they are run.
        See http://docs.python.org/library/unittest.html#unittest.main
        for full argument list.
        """
        from tornado4.options import define, options, parse_command_line

        define('exception_on_interrupt', type=bool, default=True,
               help=("If true (default), ctrl-c raises a KeyboardInterrupt "
                     "exception.  This prints a stack trace but cannot interrupt "
                     "certain operations.  If false, the process is more reliably "
                     "killed, but does not print a stack trace."))

        # support the same options as unittest's command-line interface
        define('verbose', type=bool)
        define('quiet', type=bool)
        define('failfast', type=bool)
        define('catch', type=bool)
        define('buffer', type=bool)

        argv = [sys.argv[0]] + parse_command_line(sys.argv)

        if not options.exception_on_interrupt:
            signal.signal(signal.SIGINT, signal.SIG_DFL)

        if options.verbose is not None:
            kwargs['verbosity'] = 2
        if options.quiet is not None:
            kwargs['verbosity'] = 0
        if options.failfast is not None:
            kwargs['failfast'] = True
        if options.catch is not None:
            kwargs['catchbreak'] = True
        if options.buffer is not None:
            kwargs['buffer'] = True

        if __name__ == '__main__' and len(argv) == 1:
            print("No tests specified", file=sys.stderr)
            sys.exit(1)
        try:
            # In order to be able to run tests by their fully-qualified name
            # on the command line without importing all tests here,
            # module must be set to None.  Python 3.2's unittest.main ignores
            # defaultTest if no module is given (it tries to do its own
            # test discovery, which is incompatible with auto2to3), so don't
            # set module if we're not asking for a specific test.
            if len(argv) > 1:
                unittest.main(module=None, argv=argv, **kwargs)
            else:
                unittest.main(defaultTest="all", argv=argv, **kwargs)
        except SystemExit as e:
            if e.code == 0:
                gen_log.info('PASS')
            else:
                gen_log.error('FAIL')
            raise

    if __name__ == '__main__':
        main()