python_utils_test.py

# coding: utf-8
#
# Copyright 2019 The Oppia Authors. All Rights Reserved.
#
# 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.

"""Tests for feature detection utilities for Python 2 and Python 3."""

from __future__ import absolute_import
from __future__ import unicode_literals

import ast
import builtins
import io
import sys
import tempfile
import unittest

from core.tests import test_utils
from core.tests.data import unicode_and_str_handler
import python_utils


class PythonUtilsTests(test_utils.GenericTestBase):
    """Tests for feature detection utilities that are common for Python 2 and
    Python 3.
    """

    def test_get_args_of_function_node(self):
        function_txt = b"""def _mock_function(arg1, arg2):
                      pass"""

        ast_node = ast.walk(ast.parse(function_txt))
        function_node = [n for n in ast_node if isinstance(n, ast.FunctionDef)]
        args_list = python_utils.get_args_of_function_node(function_node[0], [])
        self.assertEqual(args_list, ['arg1', 'arg2'])

    def test_open_file(self):
        with python_utils.open_file('python_utils.py', 'r') as f:
            file_content = f.readlines()
            self.assertIsNotNone(file_content)

    def test_can_not_open_file(self):
        with self.assertRaisesRegexp(
            IOError, 'Unable to open file: invalid_file.py'):
            with python_utils.open_file('invalid_file.py', 'r') as f:
                f.readlines()

    def test_url_quote(self):
        self.assertEqual(
            python_utils.url_quote('/~connolly/'), '/~connolly/')

    def test_url_encode(self):
        url_dict = {'url': 'http://myapp/my%20test/'}
        self.assertEqual(
            python_utils.url_encode(url_dict, doseq=True),
            'url=http%3A%2F%2Fmyapp%2Fmy%2520test%2F')
        self.assertEqual(
            python_utils.url_encode(url_dict, doseq=False),
            'url=http%3A%2F%2Fmyapp%2Fmy%2520test%2F')

    def test_url_retrieve(self):
        tmp_file = tempfile.NamedTemporaryFile()
        tmp_file.name = 'temp_file.txt'
        python_utils.url_retrieve(
            'http://www.google.com', filename='temp_file.txt')

        with python_utils.open_file('temp_file.txt', 'rb', encoding=None) as f:
            content = f.read()

        self.assertIn(b'<title>Google</title>', content)
        tmp_file.close()

    def test_url_open(self):
        response = python_utils.url_open('http://www.google.com')
        self.assertEqual(response.getcode(), 200)
        self.assertEqual(response.url, 'http://www.google.com')

    def test_url_request(self):
        response = python_utils.url_request('http://www.google.com', None, {})
        self.assertEqual(response.get_full_url(), 'http://www.google.com')

    def test_url_unquote_plus(self):
        self.assertEqual(
            python_utils.url_unquote_plus('/El+Ni%C3%B1o/'), '/El Niño/')

    def test_divide(self):
        self.assertEqual(python_utils.divide(4, 2), 2)
        self.assertEqual(python_utils.divide(5, 2), 2)

    def test_with_metaclass(self):
        class BaseForm(python_utils.OBJECT):
            """Test baseclass."""

            pass

        class FormType1(type):
            """Test metaclass."""

            pass

        class FormType2(type):
            """Test metaclass."""

            pass

        class Form(python_utils.with_metaclass(FormType1, BaseForm)): # pylint: disable=inherit-non-class
            """Test class."""

            pass

        self.assertTrue(isinstance(Form, FormType1))
        self.assertFalse(isinstance(Form, FormType2))
        self.assertTrue(issubclass(Form, BaseForm))

    def test_with_metaclass_without_bases(self):
        class FormType(type):
            """Test metaclass."""

            pass

        class Form(python_utils.with_metaclass(FormType)): # pylint: disable=inherit-non-class
            """Test class."""

            def __init__(self):
                pass

        self.assertTrue(isinstance(Form, FormType))
        self.assertTrue(issubclass(Form, python_utils.OBJECT))

    def test_convert_to_bytes(self):
        string1 = 'Home'
        string2 = u'Лорем'
        self.assertEqual(
            python_utils.convert_to_bytes(string1),
            string1.encode(encoding='utf-8')
        )
        self.assertEqual(
            python_utils.convert_to_bytes(string2),
            string2.encode(encoding='utf-8'))

    def test_url_split(self):
        response = python_utils.url_split('http://www.google.com')
        self.assertEqual(response.geturl(), 'http://www.google.com')

    def test_url_unsplit(self):
        response = python_utils.url_split('http://www.google.com')
        self.assertEqual(
            python_utils.url_unsplit(response), 'http://www.google.com')

    def test_parse_query_string(self):
        response = python_utils.parse_query_string(
            'http://www.google.com?search=oppia')
        self.assertEqual(response, {'http://www.google.com?search': ['oppia']})

    def test_urllib_unquote(self):
        response = python_utils.urllib_unquote('/El%20Ni%C3%B1o/')
        self.assertEqual(response, '/El Niño/')

    def test_url_parse(self):
        response = python_utils.url_parse('http://www.google.com')
        self.assertEqual(response.geturl(), 'http://www.google.com')

    def test_url_join(self):
        response = python_utils.url_join(
            'http://www.cwi.nl/%7Eguido/Python.html', 'FAQ.html')
        self.assertEqual(response, 'http://www.cwi.nl/%7Eguido/FAQ.html')

    def test_recursively_convert_to_str_with_dict(self):
        test_var_1_in_unicode = python_utils.UNICODE('test_var_1')
        test_var_2_in_unicode = python_utils.UNICODE('test_var_2')
        test_var_3_in_bytes = test_var_1_in_unicode.encode(encoding='utf-8')
        test_var_4_in_bytes = test_var_2_in_unicode.encode(encoding='utf-8')
        test_dict = {
            test_var_1_in_unicode: test_var_3_in_bytes,
            test_var_2_in_unicode: test_var_4_in_bytes
        }
        self.assertEqual(
            test_dict,
            {'test_var_1': b'test_var_1', 'test_var_2': b'test_var_2'})

        for key, val in test_dict.items():
            self.assertEqual(type(key), python_utils.UNICODE)
            self.assertEqual(type(val), builtins.bytes)

        dict_in_str = python_utils._recursively_convert_to_str(test_dict)  # pylint: disable=protected-access
        self.assertEqual(
            dict_in_str,
            {'test_var_1': 'test_var_1', 'test_var_2': 'test_var_2'})

        for key, val in dict_in_str.items():
            self.assertEqual(type(key), python_utils.UNICODE)
            self.assertEqual(type(val), python_utils.UNICODE)

    def test_recursively_convert_to_str_with_nested_structure(self):
        test_var_1_in_unicode = python_utils.UNICODE('test_var_1')
        test_list_1 = [
            test_var_1_in_unicode,
            test_var_1_in_unicode.encode(encoding='utf-8'),
            'test_var_2',
            b'test_var_3',
            {'test_var_4': b'test_var_5'}
        ]
        test_dict = {test_var_1_in_unicode: test_list_1}
        self.assertEqual(
            test_dict,
            {
                'test_var_1': [
                    'test_var_1', b'test_var_1', 'test_var_2', b'test_var_3',
                    {'test_var_4': b'test_var_5'}]
            }
        )

        dict_in_str = python_utils._recursively_convert_to_str(test_dict)  # pylint: disable=protected-access
        self.assertEqual(
            dict_in_str,
            {
                'test_var_1': [
                    'test_var_1', 'test_var_1', 'test_var_2', 'test_var_3',
                    {'test_var_4': 'test_var_5'}]
            }
        )

        for key, value in dict_in_str.items():
            self.assertNotEqual(type(key), builtins.bytes)
            self.assertTrue(isinstance(key, str))

            for item in value:
                self.assertNotEqual(type(item), builtins.bytes)
                self.assertTrue(isinstance(item, (str, bytes, dict)))

            for k, v in value[-1].items():
                self.assertEqual(type(k), str)
                self.assertEqual(type(v), str)

    def test_is_string(self):
        self.assertTrue(python_utils.is_string('abc'))
        self.assertFalse(python_utils.is_string(123))
        self.assertFalse(python_utils.is_string(['a', 'b', 'c']))

    def test_get_args_of_function(self):
        def func(a, b, *c, **d): # pylint: disable=unused-argument
            """Does nothing."""
            pass
        self.assertEqual(
            python_utils.get_args_of_function(func), ['a', 'b'])

    def test_create_enum_method_and_check_its_values(self):
        """Test create_enum method."""
        enums = python_utils.create_enum('first', 'second', 'third')
        self.assertEqual(enums.first.value, 'first')
        self.assertEqual(enums.second.value, 'second')
        self.assertEqual(enums.third.value, 'third')

    def test_create_enum_method_and_check_its_names(self):
        """Test create_enum method."""
        enums = python_utils.create_enum('first', 'second', 'third')
        self.assertEqual(enums.first.name, 'first')
        self.assertEqual(enums.second.name, 'second')
        self.assertEqual(enums.third.name, 'third')

    def test_enum_for_invalid_attribute(self):
        enums = python_utils.create_enum('first', 'second', 'third')
        with self.assertRaisesRegexp(AttributeError, 'fourth'):
            getattr(enums, 'fourth')

    def test_zip_longest(self):
        self.assertEqual(
            [list(g) for g in python_utils.zip_longest(
                [0, 1, 2, 3], [4, 5, 6], [7, 8])],
            [[0, 4, 7], [1, 5, 8], [2, 6, None], [3, None, None]])
        # Zip longest with fillvalue.
        self.assertEqual(
            [''.join(g) for g in python_utils.zip_longest(
                'ABC', 'DE', 'F', fillvalue='x')],
            ['ADF', 'BEx', 'Cxx'])


@unittest.skipUnless(
    sys.version[0] == '2', 'Test cases for ensuring Python 2 behavior only')
class PythonUtilsForPython2Tests(test_utils.GenericTestBase):
    """Tests for feature detection utilities for Python 2."""

    def test_string_io(self):
        stdout = python_utils.string_io()
        self.assertIsInstance(stdout, io.StringIO)

    def test_unicode_and_str_chars_in_file(self):
        self.assertIsInstance(
            unicode_and_str_handler.SOME_STR_TEXT, python_utils.UNICODE)
        self.assertIsInstance(
            unicode_and_str_handler.SOME_UNICODE_TEXT, python_utils.UNICODE)
        self.assertIsInstance(
            unicode_and_str_handler.SOME_BINARY_TEXT, bytes)

        with python_utils.open_file(
            'core/tests/data/unicode_and_str_handler.py', 'r') as f:
            file_content = f.read()
            self.assertIsInstance(file_content, python_utils.UNICODE)


@unittest.skipUnless(
    sys.version[0] == '3', 'Test cases for ensuring Python 3 behavior only')
class PythonUtilsForPython3Tests(test_utils.GenericTestBase):
    """Tests for feature detection utilities for Python 3."""

    def test_string_io(self):
        stdout = python_utils.string_io()
        self.assertIsInstance(stdout, io.StringIO)

    def test_unicode_and_str_chars_in_file(self):
        self.assertIsInstance(unicode_and_str_handler.SOME_STR_TEXT, str)
        self.assertIsInstance(
            unicode_and_str_handler.SOME_UNICODE_TEXT, str)
        self.assertIsInstance(
            unicode_and_str_handler.SOME_BINARY_TEXT, bytes)

        with python_utils.open_file(
            'core/tests/data/unicode_and_str_handler.py', 'r') as f:
            file_content = f.read()
            self.assertIsInstance(file_content, str)