From 8d010f39869f107820421631111417298d1c5bb9 Mon Sep 17 00:00:00 2001
From: Johannes Hoppe <info@johanneshoppe.com>
Date: Tue, 26 Feb 2019 17:23:49 +0100
Subject: [PATCH] Fixed #30220 -- Added support for headless mode in selenium
 tests.

---
 django/test/selenium.py                         | 17 ++++++++++++++++-
 .../contributing/writing-code/unit-tests.txt    |  3 +++
 docs/releases/3.0.txt                           |  3 +++
 tests/runtests.py                               |  5 +++++
 4 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/django/test/selenium.py b/django/test/selenium.py
index 6e6badd933..8910faec98 100644
--- a/django/test/selenium.py
+++ b/django/test/selenium.py
@@ -17,6 +17,8 @@ class SeleniumTestCaseBase(type(LiveServerTestCase)):
     external_host = None
     # Sentinel value to differentiate browser-specific instances.
     browser = None
+    # Run browsers in headless mode.
+    headless = False
 
     def __new__(cls, name, bases, attrs):
         """
@@ -62,11 +64,24 @@ class SeleniumTestCaseBase(type(LiveServerTestCase)):
     def import_webdriver(cls, browser):
         return import_string("selenium.webdriver.%s.webdriver.WebDriver" % browser)
 
+    @classmethod
+    def import_options(cls, browser):
+        return import_string('selenium.webdriver.%s.options.Options' % browser)
+
     @classmethod
     def get_capability(cls, browser):
         from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
         return getattr(DesiredCapabilities, browser.upper())
 
+    def create_options(self):
+        options = self.import_options(self.browser)()
+        if self.headless:
+            try:
+                options.headless = True
+            except AttributeError:
+                pass  # Only Chrome and Firefox support the headless mode.
+        return options
+
     def create_webdriver(self):
         if self.selenium_hub:
             from selenium import webdriver
@@ -74,7 +89,7 @@ class SeleniumTestCaseBase(type(LiveServerTestCase)):
                 command_executor=self.selenium_hub,
                 desired_capabilities=self.get_capability(self.browser),
             )
-        return self.import_webdriver(self.browser)()
+        return self.import_webdriver(self.browser)(options=self.create_options())
 
 
 @tag('selenium')
diff --git a/docs/internals/contributing/writing-code/unit-tests.txt b/docs/internals/contributing/writing-code/unit-tests.txt
index 4cedb1ccf3..6d9074f2d1 100644
--- a/docs/internals/contributing/writing-code/unit-tests.txt
+++ b/docs/internals/contributing/writing-code/unit-tests.txt
@@ -230,6 +230,9 @@ See the `selenium.webdriver`_ package for the list of available browsers.
 Specifying ``--selenium`` automatically sets ``--tags=selenium`` to run only
 the tests that require selenium.
 
+Some browsers (e.g. Chrome or Firefox) support headless testing, which can be
+faster and more stable. Add the ``--headless`` option to enable this mode.
+
 .. _selenium.webdriver: https://github.com/SeleniumHQ/selenium/tree/master/py/selenium/webdriver
 
 .. _running-unit-tests-dependencies:
diff --git a/docs/releases/3.0.txt b/docs/releases/3.0.txt
index daf1ef513b..fc2aad9b17 100644
--- a/docs/releases/3.0.txt
+++ b/docs/releases/3.0.txt
@@ -254,6 +254,9 @@ Tests
   references, and entity references that refer to the same character as
   equivalent.
 
+* Django test runner now supports headless mode for selenium tests on supported
+  browsers. Add the ``--headless`` option to enable this mode.
+
 URLs
 ~~~~
 
diff --git a/tests/runtests.py b/tests/runtests.py
index 96ec30d51a..e117df709b 100755
--- a/tests/runtests.py
+++ b/tests/runtests.py
@@ -446,6 +446,10 @@ if __name__ == "__main__":
         '--selenium', action=ActionSelenium, metavar='BROWSERS',
         help='A comma-separated list of browsers to run the Selenium tests against.',
     )
+    parser.add_argument(
+        '--headless', action='store_true',
+        help='Run selenium tests in headless mode, if the browser supports the option.',
+    )
     parser.add_argument(
         '--selenium-hub',
         help='A URL for a selenium hub instance to use in combination with --selenium.',
@@ -506,6 +510,7 @@ if __name__ == "__main__":
         if options.selenium_hub:
             SeleniumTestCaseBase.selenium_hub = options.selenium_hub
             SeleniumTestCaseBase.external_host = options.external_host
+        SeleniumTestCaseBase.headless = options.headless
         SeleniumTestCaseBase.browsers = options.selenium
 
     if options.bisect: