flask/tests/test_helpers.py

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

    Various helpers.

    :copyright: (c) 2015 by Armin Ronacher.
    :license: BSD, see LICENSE for more details.
"""

import pytest

import os
import uuid
import datetime
import flask
from logging import StreamHandler
from werkzeug.exceptions import BadRequest, NotFound
from werkzeug.http import parse_cache_control_header, parse_options_header
from werkzeug.http import http_date
from flask._compat import StringIO, text_type


def has_encoding(name):
    try:
        import codecs
        codecs.lookup(name)
        return True
    except LookupError:
        return False


class TestJSON(object):

    def test_post_empty_json_adds_exception_to_response_content_in_debug(self):
        app = flask.Flask(__name__)
        app.config['DEBUG'] = True
        @app.route('/json', methods=['POST'])
        def post_json():
            flask.request.get_json()
            return None
        c = app.test_client()
        rv = c.post('/json', data=None, content_type='application/json')
        assert rv.status_code == 400
        assert b'Failed to decode JSON object' in rv.data

    def test_post_empty_json_wont_add_exception_to_response_if_no_debug(self):
        app = flask.Flask(__name__)
        app.config['DEBUG'] = False
        @app.route('/json', methods=['POST'])
        def post_json():
            flask.request.get_json()
            return None
        c = app.test_client()
        rv = c.post('/json', data=None, content_type='application/json')
        assert rv.status_code == 400
        assert b'Failed to decode JSON object' not in rv.data

    def test_json_bad_requests(self):
        app = flask.Flask(__name__)
        @app.route('/json', methods=['POST'])
        def return_json():
            return flask.jsonify(foo=text_type(flask.request.get_json()))
        c = app.test_client()
        rv = c.post('/json', data='malformed', content_type='application/json')
        assert rv.status_code == 400

    def test_json_custom_mimetypes(self):
        app = flask.Flask(__name__)
        @app.route('/json', methods=['POST'])
        def return_json():
            return flask.request.get_json()
        c = app.test_client()
        rv = c.post('/json', data='"foo"', content_type='application/x+json')
        assert rv.data == b'foo'

    def test_json_body_encoding(self):
        app = flask.Flask(__name__)
        app.testing = True
        @app.route('/')
        def index():
            return flask.request.get_json()

        c = app.test_client()
        resp = c.get('/', data=u'"Hällo Wörld"'.encode('iso-8859-15'),
                     content_type='application/json; charset=iso-8859-15')
        assert resp.data == u'Hällo Wörld'.encode('utf-8')

    def test_json_as_unicode(self):
        app = flask.Flask(__name__)

        app.config['JSON_AS_ASCII'] = True
        with app.app_context():
            rv = flask.json.dumps(u'\N{SNOWMAN}')
            assert rv == '"\\u2603"'

        app.config['JSON_AS_ASCII'] = False
        with app.app_context():
            rv = flask.json.dumps(u'\N{SNOWMAN}')
            assert rv == u'"\u2603"'

    def test_json_dump_to_file(self):
        app = flask.Flask(__name__)
        test_data = {'name': 'Flask'}
        out = StringIO()

        with app.app_context():
            flask.json.dump(test_data, out)
            out.seek(0)
            rv = flask.json.load(out)
            assert rv == test_data

    def test_jsonify_basic_types(self):
        """Test jsonify with basic types."""
        # Should be able to use pytest parametrize on this, but I couldn't
        # figure out the correct syntax
        # https://pytest.org/latest/parametrize.html#pytest-mark-parametrize-parametrizing-test-functions
        test_data = (0, 1, 23, 3.14, 's', "longer string", True, False,)
        app = flask.Flask(__name__)
        c = app.test_client()
        for i, d in enumerate(test_data):
            url = '/jsonify_basic_types{0}'.format(i)
            app.add_url_rule(url, str(i), lambda x=d: flask.jsonify(x))
            rv = c.get(url)
            assert rv.mimetype == 'application/json'
            assert flask.json.loads(rv.data) == d

    def test_jsonify_dicts(self):
        """Test jsonify with dicts and kwargs unpacking."""
        d = dict(
            a=0, b=23, c=3.14, d='t', e='Hi', f=True, g=False,
            h=['test list', 10, False],
            i={'test':'dict'}
        )
        app = flask.Flask(__name__)
        @app.route('/kw')
        def return_kwargs():
            return flask.jsonify(**d)
        @app.route('/dict')
        def return_dict():
            return flask.jsonify(d)
        c = app.test_client()
        for url in '/kw', '/dict':
            rv = c.get(url)
            assert rv.mimetype == 'application/json'
            assert flask.json.loads(rv.data) == d

    def test_jsonify_arrays(self):
        """Test jsonify of lists and args unpacking."""
        l = [
            0, 42, 3.14, 't', 'hello', True, False,
            ['test list', 2, False],
            {'test':'dict'}
        ]
        app = flask.Flask(__name__)
        @app.route('/args_unpack')
        def return_args_unpack():
            return flask.jsonify(*l)
        @app.route('/array')
        def return_array():
            return flask.jsonify(l)
        c = app.test_client()
        for url in '/args_unpack', '/array':
            rv = c.get(url)
            assert rv.mimetype == 'application/json'
            assert flask.json.loads(rv.data) == l

    def test_jsonify_date_types(self):
        """Test jsonify with datetime.date and datetime.datetime types."""

        test_dates = (
            datetime.datetime(1973, 3, 11, 6, 30, 45),
            datetime.date(1975, 1, 5)
        )

        app = flask.Flask(__name__)
        c = app.test_client()

        for i, d in enumerate(test_dates):
            url = '/datetest{0}'.format(i)
            app.add_url_rule(url, str(i), lambda val=d: flask.jsonify(x=val))
            rv = c.get(url)
            assert rv.mimetype == 'application/json'
            assert flask.json.loads(rv.data)['x'] == http_date(d.timetuple())

    def test_jsonify_uuid_types(self):
        """Test jsonify with uuid.UUID types"""

        test_uuid = uuid.UUID(bytes=b'\xDE\xAD\xBE\xEF'*4)

        app = flask.Flask(__name__)
        url = '/uuid_test'
        app.add_url_rule(url, url, lambda: flask.jsonify(x=test_uuid))

        c = app.test_client()
        rv = c.get(url)

        rv_x = flask.json.loads(rv.data)['x']
        assert rv_x == str(test_uuid)
        rv_uuid = uuid.UUID(rv_x)
        assert rv_uuid == test_uuid

    def test_json_attr(self):
        app = flask.Flask(__name__)
        @app.route('/add', methods=['POST'])
        def add():
            json = flask.request.get_json()
            return text_type(json['a'] + json['b'])
        c = app.test_client()
        rv = c.post('/add', data=flask.json.dumps({'a': 1, 'b': 2}),
                            content_type='application/json')
        assert rv.data == b'3'

    def test_template_escaping(self):
        app = flask.Flask(__name__)
        render = flask.render_template_string
        with app.test_request_context():
            rv = flask.json.htmlsafe_dumps('</script>')
            assert rv == u'"\\u003c/script\\u003e"'
            assert type(rv) == text_type
            rv = render('{{ "</script>"|tojson }}')
            assert rv == '"\\u003c/script\\u003e"'
            rv = render('{{ "<\0/script>"|tojson }}')
            assert rv == '"\\u003c\\u0000/script\\u003e"'
            rv = render('{{ "<!--<script>"|tojson }}')
            assert rv == '"\\u003c!--\\u003cscript\\u003e"'
            rv = render('{{ "&"|tojson }}')
            assert rv == '"\\u0026"'
            rv = render('{{ "\'"|tojson }}')
            assert rv == '"\\u0027"'
            rv = render("<a ng-data='{{ data|tojson }}'></a>",
                data={'x': ["foo", "bar", "baz'"]})
            assert rv == '<a ng-data=\'{"x": ["foo", "bar", "baz\\u0027"]}\'></a>'

    def test_json_customization(self):
        class X(object):
            def __init__(self, val):
                self.val = val
        class MyEncoder(flask.json.JSONEncoder):
            def default(self, o):
                if isinstance(o, X):
                    return '<%d>' % o.val
                return flask.json.JSONEncoder.default(self, o)
        class MyDecoder(flask.json.JSONDecoder):
            def __init__(self, *args, **kwargs):
                kwargs.setdefault('object_hook', self.object_hook)
                flask.json.JSONDecoder.__init__(self, *args, **kwargs)
            def object_hook(self, obj):
                if len(obj) == 1 and '_foo' in obj:
                    return X(obj['_foo'])
                return obj
        app = flask.Flask(__name__)
        app.testing = True
        app.json_encoder = MyEncoder
        app.json_decoder = MyDecoder
        @app.route('/', methods=['POST'])
        def index():
            return flask.json.dumps(flask.request.get_json()['x'])
        c = app.test_client()
        rv = c.post('/', data=flask.json.dumps({
            'x': {'_foo': 42}
        }), content_type='application/json')
        assert rv.data == b'"<42>"'

    def test_modified_url_encoding(self):
        class ModifiedRequest(flask.Request):
            url_charset = 'euc-kr'
        app = flask.Flask(__name__)
        app.testing = True
        app.request_class = ModifiedRequest
        app.url_map.charset = 'euc-kr'

        @app.route('/')
        def index():
            return flask.request.args['foo']

        rv = app.test_client().get(u'/?foo=정상처리'.encode('euc-kr'))
        assert rv.status_code == 200
        assert rv.data == u'정상처리'.encode('utf-8')

    if not has_encoding('euc-kr'):
        test_modified_url_encoding = None

    def test_json_key_sorting(self):
        app = flask.Flask(__name__)
        app.testing = True
        assert app.config['JSON_SORT_KEYS'] == True
        d = dict.fromkeys(range(20), 'foo')

        @app.route('/')
        def index():
            return flask.jsonify(values=d)

        c = app.test_client()
        rv = c.get('/')
        lines = [x.strip() for x in rv.data.strip().decode('utf-8').splitlines()]
        sorted_by_str = [
            '{',
            '"values": {',
            '"0": "foo",',
            '"1": "foo",',
            '"10": "foo",',
            '"11": "foo",',
            '"12": "foo",',
            '"13": "foo",',
            '"14": "foo",',
            '"15": "foo",',
            '"16": "foo",',
            '"17": "foo",',
            '"18": "foo",',
            '"19": "foo",',
            '"2": "foo",',
            '"3": "foo",',
            '"4": "foo",',
            '"5": "foo",',
            '"6": "foo",',
            '"7": "foo",',
            '"8": "foo",',
            '"9": "foo"',
            '}',
            '}'
        ]
        sorted_by_int = [
            '{',
            '"values": {',
            '"0": "foo",',
            '"1": "foo",',
            '"2": "foo",',
            '"3": "foo",',
            '"4": "foo",',
            '"5": "foo",',
            '"6": "foo",',
            '"7": "foo",',
            '"8": "foo",',
            '"9": "foo",',
            '"10": "foo",',
            '"11": "foo",',
            '"12": "foo",',
            '"13": "foo",',
            '"14": "foo",',
            '"15": "foo",',
            '"16": "foo",',
            '"17": "foo",',
            '"18": "foo",',
            '"19": "foo"',
            '}',
            '}'
        ]

        try:
            assert lines == sorted_by_int
        except AssertionError:
            assert lines == sorted_by_str

class TestSendfile(object):

    def test_send_file_regular(self):
        app = flask.Flask(__name__)
        with app.test_request_context():
            rv = flask.send_file('static/index.html')
            assert rv.direct_passthrough
            assert rv.mimetype == 'text/html'
            with app.open_resource('static/index.html') as f:
                rv.direct_passthrough = False
                assert rv.data == f.read()
            rv.close()

    def test_send_file_xsendfile(self, catch_deprecation_warnings):
        app = flask.Flask(__name__)
        app.use_x_sendfile = True
        with app.test_request_context():
            rv = flask.send_file('static/index.html')
            assert rv.direct_passthrough
            assert 'x-sendfile' in rv.headers
            assert rv.headers['x-sendfile'] == \
                os.path.join(app.root_path, 'static/index.html')
            assert rv.mimetype == 'text/html'
            rv.close()

    def test_send_file_last_modified(self):
        app = flask.Flask(__name__)
        last_modified = datetime.datetime(1999, 1, 1)

        @app.route('/')
        def index():
            return flask.send_file(StringIO("party like it's"),
                                   last_modified=last_modified,
                                   mimetype='text/plain')

        c = app.test_client()
        rv = c.get('/')
        assert rv.last_modified == last_modified

    def test_send_file_object_without_mimetype(self):
        app = flask.Flask(__name__)

        with app.test_request_context():
            with pytest.raises(ValueError) as excinfo:
                flask.send_file(StringIO("LOL"))
            assert 'Unable to infer MIME-type' in str(excinfo)
            assert 'no filename is available' in str(excinfo)

        with app.test_request_context():
            with pytest.raises(ValueError) as excinfo:
                flask.send_file(StringIO("LOL"), attachment_filename='filename')
            assert "Unable to infer MIME-type from filename 'filename'" in str(excinfo)

    def test_send_file_object(self):
        app = flask.Flask(__name__)

        with app.test_request_context():
            with open(os.path.join(app.root_path, 'static/index.html'), mode='rb') as f:
                rv = flask.send_file(f, mimetype='text/html')
                rv.direct_passthrough = False
                with app.open_resource('static/index.html') as f:
                    assert rv.data == f.read()
                assert rv.mimetype == 'text/html'
                rv.close()

        app.use_x_sendfile = True

        with app.test_request_context():
            with open(os.path.join(app.root_path, 'static/index.html')) as f:
                rv = flask.send_file(f, mimetype='text/html')
                assert rv.mimetype == 'text/html'
                assert 'x-sendfile' not in rv.headers
                rv.close()

        app.use_x_sendfile = False
        with app.test_request_context():
            f = StringIO('Test')
            rv = flask.send_file(f, mimetype='application/octet-stream')
            rv.direct_passthrough = False
            assert rv.data == b'Test'
            assert rv.mimetype == 'application/octet-stream'
            rv.close()

            class PyStringIO(object):
                def __init__(self, *args, **kwargs):
                    self._io = StringIO(*args, **kwargs)
                def __getattr__(self, name):
                    return getattr(self._io, name)
            f = PyStringIO('Test')
            f.name = 'test.txt'
            rv = flask.send_file(f, attachment_filename=f.name)
            rv.direct_passthrough = False
            assert rv.data == b'Test'
            assert rv.mimetype == 'text/plain'
            rv.close()

            f = StringIO('Test')
            rv = flask.send_file(f, mimetype='text/plain')
            rv.direct_passthrough = False
            assert rv.data == b'Test'
            assert rv.mimetype == 'text/plain'
            rv.close()

        app.use_x_sendfile = True

        with app.test_request_context():
            f = StringIO('Test')
            rv = flask.send_file(f, mimetype='text/html')
            assert 'x-sendfile' not in rv.headers
            rv.close()

    def test_attachment(self):
        app = flask.Flask(__name__)
        with app.test_request_context():
            with open(os.path.join(app.root_path, 'static/index.html')) as f:
                rv = flask.send_file(f, as_attachment=True,
                                     attachment_filename='index.html')
                value, options = \
                    parse_options_header(rv.headers['Content-Disposition'])
                assert value == 'attachment'
                rv.close()

        with app.test_request_context():
            assert options['filename'] == 'index.html'
            rv = flask.send_file('static/index.html', as_attachment=True)
            value, options = parse_options_header(rv.headers['Content-Disposition'])
            assert value == 'attachment'
            assert options['filename'] == 'index.html'
            rv.close()

        with app.test_request_context():
            rv = flask.send_file(StringIO('Test'), as_attachment=True,
                                 attachment_filename='index.txt',
                                 add_etags=False)
            assert rv.mimetype == 'text/plain'
            value, options = parse_options_header(rv.headers['Content-Disposition'])
            assert value == 'attachment'
            assert options['filename'] == 'index.txt'
            rv.close()

    def test_static_file(self):
        app = flask.Flask(__name__)
        # default cache timeout is 12 hours
        with app.test_request_context():
            # Test with static file handler.
            rv = app.send_static_file('index.html')
            cc = parse_cache_control_header(rv.headers['Cache-Control'])
            assert cc.max_age == 12 * 60 * 60
            rv.close()
            # Test again with direct use of send_file utility.
            rv = flask.send_file('static/index.html')
            cc = parse_cache_control_header(rv.headers['Cache-Control'])
            assert cc.max_age == 12 * 60 * 60
            rv.close()
        app.config['SEND_FILE_MAX_AGE_DEFAULT'] = 3600
        with app.test_request_context():
            # Test with static file handler.
            rv = app.send_static_file('index.html')
            cc = parse_cache_control_header(rv.headers['Cache-Control'])
            assert cc.max_age == 3600
            rv.close()
            # Test again with direct use of send_file utility.
            rv = flask.send_file('static/index.html')
            cc = parse_cache_control_header(rv.headers['Cache-Control'])
            assert cc.max_age == 3600
            rv.close()
        class StaticFileApp(flask.Flask):
            def get_send_file_max_age(self, filename):
                return 10
        app = StaticFileApp(__name__)
        with app.test_request_context():
            # Test with static file handler.
            rv = app.send_static_file('index.html')
            cc = parse_cache_control_header(rv.headers['Cache-Control'])
            assert cc.max_age == 10
            rv.close()
            # Test again with direct use of send_file utility.
            rv = flask.send_file('static/index.html')
            cc = parse_cache_control_header(rv.headers['Cache-Control'])
            assert cc.max_age == 10
            rv.close()

    def test_send_from_directory(self):
        app = flask.Flask(__name__)
        app.testing = True
        app.root_path = os.path.join(os.path.dirname(__file__),
                                     'test_apps', 'subdomaintestmodule')
        with app.test_request_context():
            rv = flask.send_from_directory('static', 'hello.txt')
            rv.direct_passthrough = False
            assert rv.data.strip() == b'Hello Subdomain'
            rv.close()

    def test_send_from_directory_bad_request(self):
        app = flask.Flask(__name__)
        app.testing = True
        app.root_path = os.path.join(os.path.dirname(__file__),
                                     'test_apps', 'subdomaintestmodule')
        with app.test_request_context():
            with pytest.raises(BadRequest):
                flask.send_from_directory('static', 'bad\x00')

class TestLogging(object):

    def test_logger_cache(self):
        app = flask.Flask(__name__)
        logger1 = app.logger
        assert app.logger is logger1
        assert logger1.name == __name__
        app.logger_name = __name__ + '/test_logger_cache'
        assert app.logger is not logger1

    def test_debug_log(self, capsys):
        app = flask.Flask(__name__)
        app.debug = True

        @app.route('/')
        def index():
            app.logger.warning('the standard library is dead')
            app.logger.debug('this is a debug statement')
            return ''

        @app.route('/exc')
        def exc():
            1 // 0

        with app.test_client() as c:
            c.get('/')
            out, err = capsys.readouterr()
            assert 'WARNING in test_helpers [' in err
            assert os.path.basename(__file__.rsplit('.', 1)[0] + '.py') in err
            assert 'the standard library is dead' in err
            assert 'this is a debug statement' in err

            with pytest.raises(ZeroDivisionError):
                c.get('/exc')

    def test_debug_log_override(self):
        app = flask.Flask(__name__)
        app.debug = True
        app.logger_name = 'flask_tests/test_debug_log_override'
        app.logger.level = 10
        assert app.logger.level == 10

    def test_exception_logging(self):
        out = StringIO()
        app = flask.Flask(__name__)
        app.config['LOGGER_HANDLER_POLICY'] = 'never'
        app.logger_name = 'flask_tests/test_exception_logging'
        app.logger.addHandler(StreamHandler(out))

        @app.route('/')
        def index():
            1 // 0

        rv = app.test_client().get('/')
        assert rv.status_code == 500
        assert b'Internal Server Error' in rv.data

        err = out.getvalue()
        assert 'Exception on / [GET]' in err
        assert 'Traceback (most recent call last):' in err
        assert '1 // 0' in err
        assert 'ZeroDivisionError:' in err

    def test_processor_exceptions(self):
        app = flask.Flask(__name__)
        app.config['LOGGER_HANDLER_POLICY'] = 'never'
        @app.before_request
        def before_request():
            if trigger == 'before':
                1 // 0
        @app.after_request
        def after_request(response):
            if trigger == 'after':
                1 // 0
            return response
        @app.route('/')
        def index():
            return 'Foo'
        @app.errorhandler(500)
        def internal_server_error(e):
            return 'Hello Server Error', 500
        for trigger in 'before', 'after':
            rv = app.test_client().get('/')
            assert rv.status_code == 500
            assert rv.data == b'Hello Server Error'

    def test_url_for_with_anchor(self):
        app = flask.Flask(__name__)
        @app.route('/')
        def index():
            return '42'
        with app.test_request_context():
            assert flask.url_for('index', _anchor='x y') == '/#x%20y'

    def test_url_for_with_scheme(self):
        app = flask.Flask(__name__)
        @app.route('/')
        def index():
            return '42'
        with app.test_request_context():
            assert flask.url_for('index', _external=True, _scheme='https') == 'https://localhost/'

    def test_url_for_with_scheme_not_external(self):
        app = flask.Flask(__name__)
        @app.route('/')
        def index():
            return '42'
        with app.test_request_context():
            pytest.raises(ValueError,
                               flask.url_for,
                               'index',
                               _scheme='https')

    def test_url_for_with_alternating_schemes(self):
        app = flask.Flask(__name__)
        @app.route('/')
        def index():
            return '42'
        with app.test_request_context():
            assert flask.url_for('index', _external=True) == 'http://localhost/'
            assert flask.url_for('index', _external=True, _scheme='https') == 'https://localhost/'
            assert flask.url_for('index', _external=True) == 'http://localhost/'

    def test_url_with_method(self):
        from flask.views import MethodView
        app = flask.Flask(__name__)
        class MyView(MethodView):
            def get(self, id=None):
                if id is None:
                    return 'List'
                return 'Get %d' % id
            def post(self):
                return 'Create'
        myview = MyView.as_view('myview')
        app.add_url_rule('/myview/', methods=['GET'],
                         view_func=myview)
        app.add_url_rule('/myview/<int:id>', methods=['GET'],
                         view_func=myview)
        app.add_url_rule('/myview/create', methods=['POST'],
                         view_func=myview)

        with app.test_request_context():
            assert flask.url_for('myview', _method='GET') == '/myview/'
            assert flask.url_for('myview', id=42, _method='GET') == '/myview/42'
            assert flask.url_for('myview', _method='POST') == '/myview/create'


class TestNoImports(object):
    """Test Flasks are created without import.

    Avoiding ``__import__`` helps create Flask instances where there are errors
    at import time.  Those runtime errors will be apparent to the user soon
    enough, but tools which build Flask instances meta-programmatically benefit
    from a Flask which does not ``__import__``.  Instead of importing to
    retrieve file paths or metadata on a module or package, use the pkgutil and
    imp modules in the Python standard library.
    """

    def test_name_with_import_error(self, modules_tmpdir):
        modules_tmpdir.join('importerror.py').write('raise NotImplementedError()')
        try:
            flask.Flask('importerror')
        except NotImplementedError:
            assert False, 'Flask(import_name) is importing import_name.'


class TestStreaming(object):

    def test_streaming_with_context(self):
        app = flask.Flask(__name__)
        app.testing = True
        @app.route('/')
        def index():
            def generate():
                yield 'Hello '
                yield flask.request.args['name']
                yield '!'
            return flask.Response(flask.stream_with_context(generate()))
        c = app.test_client()
        rv = c.get('/?name=World')
        assert rv.data == b'Hello World!'

    def test_streaming_with_context_as_decorator(self):
        app = flask.Flask(__name__)
        app.testing = True
        @app.route('/')
        def index():
            @flask.stream_with_context
            def generate(hello):
                yield hello
                yield flask.request.args['name']
                yield '!'
            return flask.Response(generate('Hello '))
        c = app.test_client()
        rv = c.get('/?name=World')
        assert rv.data == b'Hello World!'

    def test_streaming_with_context_and_custom_close(self):
        app = flask.Flask(__name__)
        app.testing = True
        called = []
        class Wrapper(object):
            def __init__(self, gen):
                self._gen = gen
            def __iter__(self):
                return self
            def close(self):
                called.append(42)
            def __next__(self):
                return next(self._gen)
            next = __next__
        @app.route('/')
        def index():
            def generate():
                yield 'Hello '
                yield flask.request.args['name']
                yield '!'
            return flask.Response(flask.stream_with_context(
                Wrapper(generate())))
        c = app.test_client()
        rv = c.get('/?name=World')
        assert rv.data == b'Hello World!'
        assert called == [42]


class TestSafeJoin(object):

    def test_safe_join(self):
        # Valid combinations of *args and expected joined paths.
        passing = (
            (('a/b/c', ), 'a/b/c'),
            (('/', 'a/', 'b/', 'c/', ), '/a/b/c'),
            (('a', 'b', 'c', ), 'a/b/c'),
            (('/a', 'b/c', ), '/a/b/c'),
            (('a/b', 'X/../c'), 'a/b/c', ),
            (('/a/b', 'c/X/..'), '/a/b/c', ),
            # If last path is '' add a slash
            (('/a/b/c', '', ), '/a/b/c/', ),
            # Preserve dot slash
            (('/a/b/c', './', ), '/a/b/c/.', ),
            (('a/b/c', 'X/..'), 'a/b/c/.', ),
            # Base directory is always considered safe
            (('../', 'a/b/c'), '../a/b/c'),
            (('/..', ), '/..'),
        )

        for args, expected in passing:
            assert flask.safe_join(*args) == expected

    def test_safe_join_exceptions(self):
        # Should raise werkzeug.exceptions.NotFound on unsafe joins.
        failing = (
            # path.isabs and ``..'' checks
            ('/a', 'b', '/c'),
            ('/a', '../b/c', ),
            ('/a', '..', 'b/c'),
            # Boundaries violations after path normalization
            ('/a', 'b/../b/../../c', ),
            ('/a', 'b', 'c/../..'),
            ('/a', 'b/../../c', ),
        )

        for args in failing:
            with pytest.raises(NotFound):
                print(flask.safe_join(*args))