#15557,#15447,#15509: webbrowser test suite added.

Initial patch by Anton Barkovsky, refined a bit by me to further subdivide the
test methods.  Provides tests for the previous two bug fix commits.

Lib/test/test_webbrowser.py

+import webbrowser
+import unittest
+import subprocess
+from unittest import mock
+from test import support
+
+
+URL = 'http://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):
+        """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.
+
+        """
+        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 MozillaCommandTest(CommandTestMixin, unittest.TestCase):
+
+    browser_class = webbrowser.Mozilla
+
+    def test_open(self):
+        self._test('open',
+                   options=['-raise', '-remote'],
+                   arguments=['openURL({})'.format(URL)])
+
+    def test_open_with_autoraise_false(self):
+        self._test('open', kw=dict(autoraise=False),
+                   options=['-noraise', '-remote'],
+                   arguments=['openURL({})'.format(URL)])
+
+    def test_open_new(self):
+        self._test('open_new',
+                   options=['-raise', '-remote'],
+                   arguments=['openURL({},new-window)'.format(URL)])
+
+    def test_open_new_tab(self):
+        self._test('open_new_tab',
+                   options=['-raise', '-remote'],
+                   arguments=['openURL({},new-tab)'.format(URL)])
+
+
+class GaleonCommandTest(CommandTestMixin, unittest.TestCase):
+
+    browser_class = webbrowser.Galeon
+
+    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=['-remote'],
+                   arguments=['openURL({})'.format(URL)])
+
+    def test_open_with_autoraise_false(self):
+        self._test('open', kw=dict(autoraise=False),
+                   options=['-remote', '-noraise'],
+                   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(self):
+        self._test('open_new_tab',
+                   options=['-remote'],
+                   arguments=['openURL({},new-page)'.format(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)])
+
+
+if __name__=='__main__':
+    unittest.main()

Misc/NEWS

@@ -42,6 +42,9 @@ Tests
 - Issue #15802: Fix test logic in TestMaildir.test_create_tmp. Patch
   by Serhiy Storchaka.
 
+- Issue #15557: Added a test suite for the webbrowser module, thanks
+  to Anton Barkovsky.
+
 Build
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