acceptance tests - retry getting selenium webdriver instance of Conne…

…ctionError raised

CHANGES.rst

@@ -31,6 +31,7 @@ Unreleased Changes
 * Add support for writing tests of data manipulation during database migrations, and write tests for the migration in for Issue 105, above.
 * Add support for ``BIWEEKLYBUDGET_LOG_FILE`` environment variable to cause Flask application logs to go to a file *in addition to* STDOUT.
 * Add support for ``SQL_POOL_PRE_PING`` environment variable to enable SQLAlchemy ``pool_pre_ping`` feature (see `Disconnect Handling - Pessimistic <http://docs.sqlalchemy.org/en/latest/core/pooling.html#pool-disconnects-pessimistic>`_) for resource-constrained systems.
+* Modify acceptance tests to retry up to 3 times, 3 seconds apart, if a ConnectionError (or subclass thereof) is raised when constructing the Selenium driver instance. This is a workaround for intermittent ConnectionResetErrors in TravisCI.
 
 0.7.1 (2018-01-10)
 ------------------

biweeklybudget/tests/conftest.py

@@ -45,6 +45,8 @@
 from time import time
 from tempfile import mkstemp
 
+from retrying import retry
+
 import biweeklybudget.settings
 from biweeklybudget.tests.fixtures.sampledata import SampleDataLoader
 from biweeklybudget.tests.sqlhelpers import restore_mysqldump, do_mysqldump
@@ -59,6 +61,8 @@
 
 try:
     import pytest_selenium.pytest_selenium
+    from selenium.webdriver.support.event_firing_webdriver import \
+        EventFiringWebDriver
     HAVE_PYTEST_SELENIUM = True
 except ImportError:
     HAVE_PYTEST_SELENIUM = False
@@ -230,19 +234,63 @@ def base_url(testflask):
     return testflask.url()
 
 
-@pytest.fixture
-def selenium(selenium):
+def retry_if_conn_error(ex):
+    return isinstance(ex, ConnectionError)
+
+
+@retry(
+    stop_max_attempt_number=3, wait_fixed=3000,
+    retry_on_exception=retry_if_conn_error
+)
+def get_driver_for_class(driver_class, driver_kwargs):
+    """
+    Wrapper around the selenium ``driver()`` fixture's
+    ``driver_class(**driver_kwargs)`` call that retries up to 3 times, 3
+    seconds apart, if a ConnectionError is raised.
+    """
+    return driver_class(**driver_kwargs)
+
+
+@pytest.yield_fixture
+def driver(request, driver_class, driver_kwargs):
+    """
+    Returns a WebDriver instance based on options and capabilities
+
+    This is copied from pytest-selenium 1.11.4, but modified to retry getting
+    the driver up to 3 times to cope with intermittent connection resets in
+    TravisCI. We ripped the original ``driver = driver_class(**driver_kwargs)``
+    out and replaced it with the ``get_driver_for_class()`` function, which
+    is wrapped in the retrying package's ``@retry`` decorator.
+    """
+    driver = get_driver_for_class(driver_class, driver_kwargs)
+
+    event_listener = request.config.getoption('event_listener')
+    if event_listener is not None:
+        # Import the specified event listener and wrap the driver instance
+        mod_name, class_name = event_listener.rsplit('.', 1)
+        mod = __import__(mod_name, fromlist=[class_name])
+        event_listener = getattr(mod, class_name)
+        if not isinstance(driver, EventFiringWebDriver):
+            driver = EventFiringWebDriver(driver, event_listener())
+
+    request.node._driver = driver
+    yield driver
+    driver.quit()
+
+
+@pytest.yield_fixture
+def selenium(driver):
     """
     Per pytest-selenium docs, use this to override the selenium fixture to
     provide global common setup.
     """
-    selenium.set_window_size(1920, 1080)
-    selenium.implicitly_wait(2)
+    driver.set_window_size(1920, 1080)
+    driver.implicitly_wait(2)
     # from http://stackoverflow.com/a/13853684/211734
-    selenium.set_script_timeout(30)
+    driver.set_script_timeout(30)
     # from http://stackoverflow.com/a/17536547/211734
-    selenium.set_page_load_timeout(30)
-    return selenium
+    driver.set_page_load_timeout(30)
+    yield driver
 
 
 def _gather_screenshot(item, report, driver, summary, extra):

tox.ini

@@ -21,6 +21,7 @@ deps =
   pytest-blockage
   pytest-timeout
   alembic-verify
+  retrying
 
 passenv=CI TRAVIS* CONTINUOUS_INTEGRATION AWS* NO_REFRESH_DB DB_CONNSTRING NO_CLASS_REFRESH_DB
 setenv =
@@ -138,6 +139,7 @@ deps =
   pytest-selenium
   pytest-timeout
   alembic-verify
+  retrying
 passenv = {[testenv]passenv}
 setenv = {[testenv]setenv}
 basepython = python2.7
@@ -170,6 +172,7 @@ deps =
   freezegun
   alembic-verify
   pytest-html
+  retrying
 passenv=CI TRAVIS* CONTINUOUS_INTEGRATION NO_REFRESH_DB DB_CONNSTRING NO_CLASS_REFRESH_DB MYSQL_*
 setenv = {[testenv]setenv}
 basepython = python3.6