given a web browser instance method name along with arguments and keywords for same which defaults to the single argument url creates a browser instance from the class pointed to by self browser calls the indicated instance method with the indicated arguments and compares the resulting options and arguments passed to popen by the browser instance against the options and args lists options are compared in a position independent fashion and the arguments are compared in sequence order to whatever is left over after removing the options ensure we don t alter the real registered browser details given a web browser instance method name along with arguments and keywords for same which defaults to the single argument url creates a browser instance from the class pointed to by self browser calls the indicated instance method with the indicated arguments and compares the resulting options and arguments passed to popen by the browser instance against the options and args lists options are compared in a position independent fashion and the arguments are compared in sequence order to whatever is left over after removing the options ensure we don t alter the real registered browser details
import webbrowser
import unittest
import os
import sys
import subprocess
from unittest import mock
from test import support
from test.support import import_helper
from test.support import os_helper

if not support.has_subprocess_support:
    raise unittest.SkipTest("test webserver requires subprocess")

URL = 'https://www.example.com'
CMD_NAME = 'test'


class PopenMock(mock.MagicMock):

    def poll(self):
        return 0

    def wait(self, seconds=None):
        return 0


class CommandTestMixin:

    def _test(self, meth, *, args=[URL], kw={}, options, arguments):
        
        popen = PopenMock()
        support.patch(self, subprocess, 'Popen', popen)
        browser = self.browser_class(name=CMD_NAME)
        getattr(browser, meth)(*args, **kw)
        popen_args = subprocess.Popen.call_args[0][0]
        self.assertEqual(popen_args[0], CMD_NAME)
        popen_args.pop(0)
        for option in options:
            self.assertIn(option, popen_args)
            popen_args.pop(popen_args.index(option))
        self.assertEqual(popen_args, arguments)


class GenericBrowserCommandTest(CommandTestMixin, unittest.TestCase):

    browser_class = webbrowser.GenericBrowser

    def test_open(self):
        self._test('open',
                   options=[],
                   arguments=[URL])


class BackgroundBrowserCommandTest(CommandTestMixin, unittest.TestCase):

    browser_class = webbrowser.BackgroundBrowser

    def test_open(self):
        self._test('open',
                   options=[],
                   arguments=[URL])


class ChromeCommandTest(CommandTestMixin, unittest.TestCase):

    browser_class = webbrowser.Chrome

    def test_open(self):
        self._test('open',
                   options=[],
                   arguments=[URL])

    def test_open_with_autoraise_false(self):
        self._test('open', kw=dict(autoraise=False),
                   options=[],
                   arguments=[URL])

    def test_open_new(self):
        self._test('open_new',
                   options=['--new-window'],
                   arguments=[URL])

    def test_open_new_tab(self):
        self._test('open_new_tab',
                   options=[],
                   arguments=[URL])


class EdgeCommandTest(CommandTestMixin, unittest.TestCase):

    browser_class = webbrowser.Edge

    def test_open(self):
        self._test('open',
                   options=[],
                   arguments=[URL])

    def test_open_with_autoraise_false(self):
        self._test('open', kw=dict(autoraise=False),
                   options=[],
                   arguments=[URL])

    def test_open_new(self):
        self._test('open_new',
                   options=['--new-window'],
                   arguments=[URL])

    def test_open_new_tab(self):
        self._test('open_new_tab',
                   options=[],
                   arguments=[URL])


class MozillaCommandTest(CommandTestMixin, unittest.TestCase):

    browser_class = webbrowser.Mozilla

    def test_open(self):
        self._test('open',
                   options=[],
                   arguments=[URL])

    def test_open_with_autoraise_false(self):
        self._test('open', kw=dict(autoraise=False),
                   options=[],
                   arguments=[URL])

    def test_open_new(self):
        self._test('open_new',
                   options=[],
                   arguments=['-new-window', URL])

    def test_open_new_tab(self):
        self._test('open_new_tab',
                   options=[],
                   arguments=['-new-tab', URL])


class EpiphanyCommandTest(CommandTestMixin, unittest.TestCase):

    browser_class = webbrowser.Epiphany

    def test_open(self):
        self._test('open',
                   options=['-n'],
                   arguments=[URL])

    def test_open_with_autoraise_false(self):
        self._test('open', kw=dict(autoraise=False),
                   options=['-noraise', '-n'],
                   arguments=[URL])

    def test_open_new(self):
        self._test('open_new',
                   options=['-w'],
                   arguments=[URL])

    def test_open_new_tab(self):
        self._test('open_new_tab',
                   options=['-w'],
                   arguments=[URL])


class OperaCommandTest(CommandTestMixin, unittest.TestCase):

    browser_class = webbrowser.Opera

    def test_open(self):
        self._test('open',
                   options=[],
                   arguments=[URL])

    def test_open_with_autoraise_false(self):
        self._test('open', kw=dict(autoraise=False),
                   options=[],
                   arguments=[URL])

    def test_open_new(self):
        self._test('open_new',
                   options=['--new-window'],
                   arguments=[URL])

    def test_open_new_tab(self):
        self._test('open_new_tab',
                   options=[],
                   arguments=[URL])


class ELinksCommandTest(CommandTestMixin, unittest.TestCase):

    browser_class = webbrowser.Elinks

    def test_open(self):
        self._test('open', options=['-remote'],
                           arguments=['openURL({})'.format(URL)])

    def test_open_with_autoraise_false(self):
        self._test('open',
                   options=['-remote'],
                   arguments=['openURL({})'.format(URL)])

    def test_open_new(self):
        self._test('open_new',
                   options=['-remote'],
                   arguments=['openURL({},new-window)'.format(URL)])

    def test_open_new_tab(self):
        self._test('open_new_tab',
                   options=['-remote'],
                   arguments=['openURL({},new-tab)'.format(URL)])


class BrowserRegistrationTest(unittest.TestCase):

    def setUp(self):
        
        self._saved_tryorder = webbrowser._tryorder
        webbrowser._tryorder = []
        self._saved_browsers = webbrowser._browsers
        webbrowser._browsers = {}

    def tearDown(self):
        webbrowser._tryorder = self._saved_tryorder
        webbrowser._browsers = self._saved_browsers

    def _check_registration(self, preferred):
        class ExampleBrowser:
            pass

        expected_tryorder = []
        expected_browsers = {}

        self.assertEqual(webbrowser._tryorder, expected_tryorder)
        self.assertEqual(webbrowser._browsers, expected_browsers)

        webbrowser.register('Example1', ExampleBrowser)
        expected_tryorder = ['Example1']
        expected_browsers['example1'] = [ExampleBrowser, None]
        self.assertEqual(webbrowser._tryorder, expected_tryorder)
        self.assertEqual(webbrowser._browsers, expected_browsers)

        instance = ExampleBrowser()
        if preferred is not None:
            webbrowser.register('example2', ExampleBrowser, instance,
                                preferred=preferred)
        else:
            webbrowser.register('example2', ExampleBrowser, instance)
        if preferred:
            expected_tryorder = ['example2', 'Example1']
        else:
            expected_tryorder = ['Example1', 'example2']
        expected_browsers['example2'] = [ExampleBrowser, instance]
        self.assertEqual(webbrowser._tryorder, expected_tryorder)
        self.assertEqual(webbrowser._browsers, expected_browsers)

    def test_register(self):
        self._check_registration(preferred=False)

    def test_register_default(self):
        self._check_registration(preferred=None)

    def test_register_preferred(self):
        self._check_registration(preferred=True)


class ImportTest(unittest.TestCase):
    def test_register(self):
        webbrowser = import_helper.import_fresh_module('webbrowser')
        self.assertIsNone(webbrowser._tryorder)
        self.assertFalse(webbrowser._browsers)

        class ExampleBrowser:
            pass
        webbrowser.register('Example1', ExampleBrowser)
        self.assertTrue(webbrowser._tryorder)
        self.assertEqual(webbrowser._tryorder[-1], 'Example1')
        self.assertTrue(webbrowser._browsers)
        self.assertIn('example1', webbrowser._browsers)
        self.assertEqual(webbrowser._browsers['example1'], [ExampleBrowser, None])

    def test_get(self):
        webbrowser = import_helper.import_fresh_module('webbrowser')
        self.assertIsNone(webbrowser._tryorder)
        self.assertFalse(webbrowser._browsers)

        with self.assertRaises(webbrowser.Error):
            webbrowser.get('fakebrowser')
        self.assertIsNotNone(webbrowser._tryorder)

    def test_synthesize(self):
        webbrowser = import_helper.import_fresh_module('webbrowser')
        name = os.path.basename(sys.executable).lower()
        webbrowser.register(name, None, webbrowser.GenericBrowser(name))
        webbrowser.get(sys.executable)

    def test_environment(self):
        webbrowser = import_helper.import_fresh_module('webbrowser')
        try:
            browser = webbrowser.get().name
        except webbrowser.Error as err:
            self.skipTest(str(err))
        with os_helper.EnvironmentVarGuard() as env:
            env["BROWSER"] = browser
            webbrowser = import_helper.import_fresh_module('webbrowser')
            webbrowser.get()

    def test_environment_preferred(self):
        webbrowser = import_helper.import_fresh_module('webbrowser')
        try:
            webbrowser.get()
            least_preferred_browser = webbrowser.get(webbrowser._tryorder[-1]).name
        except (webbrowser.Error, IndexError) as err:
            self.skipTest(str(err))

        with os_helper.EnvironmentVarGuard() as env:
            env["BROWSER"] = least_preferred_browser
            webbrowser = import_helper.import_fresh_module('webbrowser')
            self.assertEqual(webbrowser.get().name, least_preferred_browser)

        with os_helper.EnvironmentVarGuard() as env:
            env["BROWSER"] = sys.executable
            webbrowser = import_helper.import_fresh_module('webbrowser')
            self.assertEqual(webbrowser.get().name, sys.executable)


if __name__=='__main__':
    unittest.main()