Accept a custom geckodriver port

By default geckodriver uses a random port. This change allows
passing a custom port number in `geckodriver_port`.

Author: gunesacar

tbselenium/tbdriver.py

@@ -39,7 +39,8 @@ def __init__(self,
                  default_bridge_type="",
                  headless=False,
                  options=None,
-                 use_custom_profile=False
+                 use_custom_profile=False,
+                 geckodriver_port=0  # by default a random port will be used
                  ):
 
         # use_custom_profile: whether to launch from and *write to* the given
@@ -79,12 +80,14 @@ def __init__(self,
             tbb_service = Service(
                 executable_path=executable_path,
                 log_path=tbb_logfile_path,
-                service_args=["--marionette-port", "2828"]
+                service_args=["--marionette-port", "2828"],
+                port=geckodriver_port
                 )
         else:
             tbb_service = Service(
                 executable_path=executable_path,
-                log_path=tbb_logfile_path
+                log_path=tbb_logfile_path,
+                port=geckodriver_port
                 )
         self.options.binary = self.tbb_fx_binary_path
         self.options.add_argument('--class')

tbselenium/test/test_tbdriver.py

@@ -10,6 +10,8 @@
 from tbselenium import common as cm
 from tbselenium.test import TBB_PATH
 from tbselenium.test.fixtures import TBDriverFixture
+from selenium.webdriver.common.utils import free_port
+from tbselenium.utils import is_busy
 
 
 class TBDriverTest(unittest.TestCase):
@@ -126,5 +128,17 @@ def test_custom_profile_and_binary(self):
         self.assertEqual(mod_time_before, mod_time_after)
 
 
+class TBDriverCustomGeckoDriverPort(unittest.TestCase):
+
+    def test_should_accept_custom_geckodriver_port(self):
+        """Make sure we accept a custom port number to run geckodriver on."""
+        random_port = free_port()
+        with TBDriverFixture(TBB_PATH, geckodriver_port=random_port) as driver:
+            driver.load_url_ensure(cm.ABOUT_TOR_URL)
+            self.assertTrue(is_busy(random_port))  # check if the port is used
+        # check if the port is closed after we quit
+        self.assertFalse(is_busy(random_port))
+
+
 if __name__ == "__main__":
     unittest.main()