Selenium + Docker

.gitlab-ci.yml

 before_script:
   - VERSION=`cat ./version`
+  - mkdir build || true
+
+variables:
+  SELENIUM_LOGS_PATH: "/scratch/tmp/7/"
 
 stages:
   - before
   - build
+  - selenium
 
 documentation:
   stage: before
@@ -16,17 +21,48 @@ snapshot:
   stage: build
   except:
     - tags
+  artifacts:
+    expire_in: 1 week
+    paths:
+      - build/
   script:
     - make VERSION=$VERSION phpunit_snapshot
     - chmod a+r qfq_$VERSION_*.zip
     - scp qfq_$VERSION_*.zip w16:qfq/snapshots/
+    - mv qfq_$VERSION_*.zip build/qfq.zip
 
 release:
   stage: build
   only:
     - tags
+  artifacts:
+    expire_in: 1 week
+    paths:
+      - build/
   script:
     - make VERSION=$VERSION phpunit_release
     - chmod a+r qfq_$VERSION_*.zip
     - scp qfq_$VERSION_*.zip w16:qfq/releases/
+    - mv qfq_$VERSION_*.zip build/qfq.zip
+
+selenium:
+  stage: selenium
+  script:
+    - unzip -q build/qfq.zip -d qfq
+    - cd docker/
+    - ./run_qfq_docker.sh -no-deploy
+    - ./deploy_to_container.sh ../qfq
+    - ./run_selenium_tests_docker.sh
+    - echo "hello"
+  after_script:
+#   remove containers and move logs to persistent location
+    - cd docker; ./remove-containers.sh <<< "y"
+    - cd ..
+    - umask 002
+    - mkdir "$SELENIUM_LOGS_PATH/$CI_COMMIT_SHORT_SHA"
+    - cp extension/Tests/selenium/selenium_logs/* "$SELENIUM_LOGS_PATH/$CI_COMMIT_SHORT_SHA/"
+    - echo "Selenium Logs copied to $SELENIUM_LOGS_PATH/$CI_COMMIT_SHORT_SHA/"
+
+
+
 

Documentation/Manual.rst

@@ -253,8 +253,8 @@ Setup a *report* to manage all *forms*:
     10 {
         # List of Forms: Do not show this list of forms if there is a form given by SIP.
         # Table header.
-        sql = SELECT CONCAT('p:{{pageAlias:T}}&form=form') as _pagen, '#', 'Name', 'Title', 'Table', '' FROM (SELECT 1) AS fake WHERE '{{form:SE}}'=''
-        head = {{'b|p:id={{pageAlias:T}}&form=copyFormFromExt|t:Copy form from ExtForm' AS _link}}
+        sql = SELECT CONCAT('p:{{pageAlias:T}}&form=form|A:data-reference=newForm') as _pagen, '#', 'Name', 'Title', 'Table', '' FROM (SELECT 1) AS fake WHERE '{{form:SE}}'=''
+        head = {{'b|p:id={{pageAlias:T}}&form=copyFormFromExt|t:Copy form from ExtForm|A:data-reference=copyForm' AS _link}}
                <table class="table table-hover qfq-table-50 tablesorter tablesorter-filter">
         tail = </table>
         rbeg = <thead><tr>
@@ -264,9 +264,9 @@ Setup a *report* to manage all *forms*:
 
         10 {
             # All forms
-            sql = SELECT CONCAT('p:{{pageAlias:T}}&form=form&r=', f.id) as _pagee
+            sql = SELECT CONCAT('p:{{pageAlias:T}}&form=form&r=', f.id, '|A:data-reference=editForm', f.name) as _pagee
                          , f.id, f.name, f.title AS '_striptags', f.tableName
-                         , CONCAT('U:form=form&r=', f.id) as _paged
+                         , CONCAT('U:form=form&r=', f.id, '|A:data-reference=deletForm') as _paged
                       FROM Form AS f
                       ORDER BY f.name
             rbeg = <tr>

Makefile

@@ -64,9 +64,7 @@ bootstrap: .npmpackages .plantuml_install .virtual_env
 	cd extension; composer update
 
 basic: .npmpackages .virtual_env
-	npm update
 	grunt default
-
 	# IMPORTANT: install composer with no-dev flag for deployment!
 	cd extension; composer install --no-dev --optimize-autoloader; cd vendor/phpoffice/phpspreadsheet; rm -rf .github bin docs samples .g* .s* .t* C* c* m* p*
 
@@ -74,9 +72,15 @@ basic: .npmpackages .virtual_env
 	wget --no-check-certificate -O support/plantuml/plantuml.jar 'https://downloads.sourceforge.net/project/plantuml/plantuml.jar'
 	touch $@
 
-.npmpackages: package.json
+.npmpackages:
 	npm ls -g grunt-cli 2>/dev/null || { echo "Please install grunt-cli npm package using 'npm install -g grunt-cli'" 1>&2 ; exit 1; }
-	npm install
+
+	# update npm at persistent location and copy node_modules (to speed up process)
+	mkdir -p /var/tmp/qfq/npm
+	/bin/cp package.json /var/tmp/qfq/npm/
+	cd /var/tmp/qfq/npm; npm update
+	/bin/cp -r /var/tmp/qfq/npm/node_modules ./
+
 	touch $@
 
 .support:

docker/README.md

+Tested on Ubuntu 16.04 with Docker version 18.09.2
+
+# Other Documentation
+
+More documentation and docker tips are located in:
+
+- https://wikiit.math.uzh.ch/it/bestpractice/Docker
+- https://systemvcs.math.uzh.ch/megger/qfq_docker
+
+# Build Images
+
+1. Clone the docker image repository:  
+```git clone https://systemvcs.math.uzh.ch/megger/qfq_docker.git```
+
+2. Build images as explained in the README.md of the image repository.
+For the below scripts to work please name the images ```python-selenium``` and ```typo3-qfq``` respectively.
+
+# Run and Interact with Containers
+
+## Run qfq in docker container from scratch
+
+1. clone qfq git project
+2. change to project directory (qfq)
+3. ```make bootstrap```
+4. ``` cd docker```
+5. ```./run_qfq_docker.sh```
+6. open the newly generated file run_qfq_docker.output and copy the value of T3_PORT. In a browser go to 127.0.0.1:<T3_PORT>.
+
+## Deploy qfq extension changes to running container
+
+Assumes you have run qfq in docker as explained above.
+
+1. change to docker directory
+2. ```./deploy_to_container.sh```
+
+## Dump QFQ and (truncated) Typo3 databases to docker directory
+
+Assumes you have run qfq in docker as explained above.
+
+1. again from the docker directory run  
+```./dump_databases.sh``` (this will overwrite the db_fixtrue_*.sql files)
+
+## Run Phpmyadmin
+
+ATTENTION: Use Firefox if Phpmyadmin login does not work in Chrome!
+
+Assumes you have run qfq in docker as explained above.
+
+1. change to docker directory and run ```./run_phpmyadmin.sh```
+2. open the file run_qfq_docker.output and copy the value of PMA_PORT. In a browser (Firefox) go to 127.0.0.1:<PMA_PORT>.
+
+## Run selenium tests on local machine (with visible browser)
+
+Assumes you have run qfq in docker as explained above.
+
+1. again from the docker directory run ```./run_selenium_tests_local.sh```
+
+## Run a single selenium test file on local machine
+
+Assumes you have run qfq in docker as explained above.
+
+1. copy T3_PORT from docker/run_qfq_docker.output
+2. Export variables (replace <T3_PORT>):  
+```export SELENIUM_URL="http://127.0.0.1:<T3_PORT>" SELENIUM_HEADLESS="no"```
+3. in extension/Tests/selenium run
+```python <selenium test file>.py```
+
+## Run selenium tests in docker container (test execution not visible)
+
+Assumes you have run qfq in docker as explained above.
+
+1. from the docker directory run ```./run_selenium_tests_docker.sh```
+
+## Permanently remove all above created containers and their data
+
+(only removes the containers listed in run_qfq_docker.output)
+
+1. from the docker directory run ```./remove-containers.sh```
+
+# TROUBLE SHOOT
+
+## WebDriverException: Message: 'chromedriver' executable needs to be in PATH
+
+1. Download Chromedriver:  
+```wget -O /tmp/chromedriver.zip http://chromedriver.storage.googleapis.com/`curl -sS chromedriver.storage.googleapis.com/LATEST_RELEASE`/chromedriver_linux64.zip```
+
+2. Unzip chromedriver to current working directory  
+```unzip /tmp/chromedriver.zip chromedriver```
+
+3. export chromedriver path environment variable before running selenium tests locally  
+```export CHROMEDRIVER_PATH=<absolute path to chromedriver>/chromedriver```
\ No newline at end of file

docker/_helper_functions.sh

@@ -34,4 +34,4 @@ function addUsernameToContainerName()
     local CONTAINER="$1"
     local CONTAINER_NAME=$(getContainerName ${CONTAINER})
     docker rename ${CONTAINER_NAME} ${USER}_${CONTAINER_NAME}
-}
+}
\ No newline at end of file

docker/deploy_to_container.sh

+#!/bin/bash -ex
+#
+# First Argument: Path to extension folder
+
+PATH_TO_EXTENSION=../extension
+if [[ "$1" ]]; then
+    PATH_TO_EXTENSION=$1
+fi
+
+source run_qfq_docker.output
+docker exec ${T3_CONTAINER} rm -rf /var/www/html/typo3conf/ext/qfq
+docker cp ${PATH_TO_EXTENSION} ${T3_CONTAINER}:/var/www/html/typo3conf/ext/qfq
+docker exec ${T3_CONTAINER} chown -R www-data:www-data /var/www/html/typo3conf/ext/qfq
+
+# call the qfq website once, since it shows an error the first time it is called
+docker exec ${T3_CONTAINER} curl 127.0.0.1:80 > /dev/null
\ No newline at end of file

docker/dump_databases.sh

+#!/bin/bash -ex
+
+source run_qfq_docker.output
+MYSQL_ROOT_PASSWORD=crazyfish123
+
+# qfq database dump
+mysqldump -u root --password=${MYSQL_ROOT_PASSWORD} --port=${DB_PORT} -h 127.0.0.1 qfq_db > db_fixture_qfq.sql
+
+# typo3 database dump, truncate unimportant tables
+to_truncate="
+TRUNCATE cache_md5params;
+TRUNCATE cache_treelist;
+TRUNCATE cf_cache_hash;
+TRUNCATE cf_cache_hash_tags;
+TRUNCATE cf_cache_imagesizes;
+TRUNCATE cf_cache_imagesizes_tags;
+TRUNCATE cf_cache_pages;
+TRUNCATE cf_cache_pagesection;
+TRUNCATE cf_cache_pagesection_tags;
+TRUNCATE cf_cache_pages_tags;
+TRUNCATE cf_cache_rootline;
+TRUNCATE cf_cache_rootline_tags;
+TRUNCATE sys_log;
+TRUNCATE sys_news;
+TRUNCATE sys_note;
+TRUNCATE tx_extensionmanager_domain_model_extension;
+"
+mysql -u root --password=${MYSQL_ROOT_PASSWORD} --port=${DB_PORT} -h 127.0.0.1 -D t3_db -e "$to_truncate"
+mysqldump -u root --password=${MYSQL_ROOT_PASSWORD} --port=${DB_PORT} -h 127.0.0.1 t3_db > db_fixture_t3.sql

docker/remove-containers.sh

+#!/bin/bash -e
+
+source _helper_functions.sh
+
+source run_qfq_docker.output
+
+echo "The following containers and their data will be deleted completely:"
+echo "$(getContainerName ${DB_CONTAINER}), $(getContainerName ${T3_CONTAINER}), $(getContainerName ${PMA_CONTAINER} 2>/dev/null || true)"
+read -p "Are you really really really sure you want to do this? (y/n): " -r
+if [[ $REPLY =~ ^[Yy]$ ]]; then
+    echo "removing..."
+	docker rm -fv ${DB_CONTAINER} || true
+    docker rm -fv ${T3_CONTAINER} || true
+    docker rm -fv ${PMA_CONTAINER} 2>/dev/null || true
+    rm run_qfq_docker.output
+    echo "done."
+fi

docker/run_phpmyadmin.sh

+#!/bin/bash -ex
+
+source run_qfq_docker.output
+source _helper_functions.sh
+
+PMA_CONTAINER_NAME= # if empty choose random
+PMA_PORT=0    # if set to 0 choose random
+
+PMA_CONTAINER=$(docker run -d --name "${PMA_CONTAINER_NAME}" -p ${PMA_PORT}:80 --link ${DB_CONTAINER}:db  phpmyadmin/phpmyadmin)
+PMA_PORT="$(getHostPort 80 ${PMA_CONTAINER})"
+addUsernameToContainerName ${PMA_CONTAINER}
+
+echo "
+PMA_CONTAINER=${PMA_CONTAINER}
+PMA_PORT=${PMA_PORT}
+" >> run_qfq_docker.output
+
+########################################
+##           User Output              ##
+########################################
+
+echo "Finished. Go to: http://localhost:${PMA_PORT}"
\ No newline at end of file

docker/run_qfq_docker.sh

+#!/bin/bash -ex
+
+source _helper_functions.sh
+
+
+########################################
+##               Config               ##
+########################################
+
+#CONTAINER_TIMEOUT=60   # stop container after this timeout (does not work with gitlab ci)
+
+
+### Config Database Container ###
+
+DB_CONTAINER_NAME=    # if empty choose random
+DB_PORT=0    # if set to 0 choose random
+MYSQL_ROOT_PASSWORD=crazyfish123
+MYSQL_USER=typo3
+MYSQL_PASSWORD=crazyfish123
+QFQ_DATABASE=qfq_db
+T3_DATABASE=t3_db
+
+
+### Config Typo3 Container ###
+
+T3_IMAGE=typo3-qfq
+T3_CONTAINER_NAME=    # if empty choose random
+T3_PORT=0    # if set to 0 choose random
+# T3_ADMINO_PASSWORD=    # typo3 password for user admino (if not set, then default is used)
+# T3_INSTALL_PASSWORD_HASH=<ReplaceWithHashGeneratedByTypo3InstallTool>
+# T3_REPLACE_ENCRYPTION_KEY=yes  # generate new key using /dev/urandom
+
+
+########################################
+##            Pre Process             ##
+########################################
+
+source run_qfq_docker.output && echo "File run_qfq_docker.output already exists. Delete it first. Abort." \
+    && exit 1 || true
+
+
+########################################
+##           DB Container             ##
+########################################
+
+DB_CONTAINER=$(docker run -d --name "${DB_CONTAINER_NAME}" \
+    -p ${DB_PORT}:3306 \
+    -e MYSQL_ROOT_PASSWORD=${MYSQL_ROOT_PASSWORD} \
+    -e MYSQL_USER=${MYSQL_USER} \
+    -e MYSQL_PASSWORD=${MYSQL_PASSWORD} \
+    mariadb:latest \
+    --character-set-server=utf8 \
+    --collation-server=utf8_general_ci)
+DB_PORT="$(getHostPort 3306 ${DB_CONTAINER})"
+addUsernameToContainerName ${DB_CONTAINER}
+
+echo "
+DB_CONTAINER=${DB_CONTAINER}
+DB_PORT=${DB_PORT}
+" >> run_qfq_docker.output
+
+if [[ "${CONTAINER_TIMEOUT}" ]]; then
+    removeContainerAfterTimeout ${CONTAINER_TIMEOUT} ${DB_CONTAINER}
+fi
+
+### import database files ###
+
+# HACK: Have to retry until database is ready. Database loading could be done earlier in image build process.
+# As described here: https://stackoverflow.com/a/49680802
+# Instead of copying the sql files in the dockerfile we could mount them in a volume!
+tries=0
+until mysql -u root --password=${MYSQL_ROOT_PASSWORD} --port=${DB_PORT} -h 127.0.0.1 \
+    -e "CREATE DATABASE ${T3_DATABASE}; CREATE DATABASE ${QFQ_DATABASE}"
+do
+	tries=$((tries+1))
+    if [[ "${tries}" -gt 30 ]]; then
+        echo "Timeout: could not connect to database."
+        exit 1;
+    fi
+    echo "Try again"
+    sleep 1
+done
+
+mysql -u root --password=${MYSQL_ROOT_PASSWORD} --port=${DB_PORT} -h 127.0.0.1 -D ${T3_DATABASE} < db_fixture_t3.sql
+mysql -u root --password=${MYSQL_ROOT_PASSWORD} --port=${DB_PORT} -h 127.0.0.1 -D ${QFQ_DATABASE} < db_fixture_qfq.sql
+mysql -u root --password=${MYSQL_ROOT_PASSWORD} --port=${DB_PORT} -h 127.0.0.1 \
+    -e "GRANT ALL PRIVILEGES ON *.* TO '${MYSQL_USER}'@'%';"
+
+
+########################################
+##           T3 Container             ##
+########################################
+
+T3_CONTAINER=$(docker run -d --name "${T3_CONTAINER_NAME}" -p ${T3_PORT}:80 --link ${DB_CONTAINER}:db ${T3_IMAGE})
+T3_PORT="$(getHostPort 80 ${T3_CONTAINER})"
+addUsernameToContainerName ${T3_CONTAINER}
+
+echo "
+T3_CONTAINER=${T3_CONTAINER}
+T3_PORT=${T3_PORT}
+" >> run_qfq_docker.output
+
+if [[ "${CONTAINER_TIMEOUT}" ]]; then
+    removeContainerAfterTimeout ${CONTAINER_TIMEOUT} ${T3_CONTAINER}
+fi
+
+### Write config files ###
+
+# QFQ config
+echo "
+<?php
+return [
+    'DB_1_USER' => '${MYSQL_USER}',
+    'DB_1_SERVER' => 'db',
+    'DB_1_PASSWORD' => '${MYSQL_PASSWORD}',
+    'DB_1_NAME' => '${QFQ_DATABASE}',
+];" > config.qfq.php
+docker cp config.qfq.php ${T3_CONTAINER}:/var/www/html/typo3conf/config.qfq.php
+rm config.qfq.php
+docker exec ${T3_CONTAINER} chown www-data:www-data /var/www/html/typo3conf/config.qfq.php
+
+# Typo3 config
+docker exec ${T3_CONTAINER} sed -i -e "s/<MYSQL_USER>/${MYSQL_USER}/g" /var/www/html/typo3conf/LocalConfiguration.php
+docker exec ${T3_CONTAINER} sed -i -e "s/<MYSQL_PASSWORD>/${MYSQL_PASSWORD}/g" /var/www/html/typo3conf/LocalConfiguration.php
+docker exec ${T3_CONTAINER} sed -i -e "s/<T3_DATABASE>/${T3_DATABASE}/g" /var/www/html/typo3conf/LocalConfiguration.php
+if [[ "${T3_INSTALL_PASSWORD_HASH}" ]]; then
+	current_hash='s/$pbkdf2-sha256$25000$1h4tjST5Wv.PyZcwfIIVvQ$kUl8homXlnaDohmt6ki0Vsji9tEaJ6tQ9vnymDCfYAY'
+	docker exec ${T3_CONTAINER} sed -i -e "s/${current_hash}/${T3_INSTALL_PASSWORD_HASH}/g" \
+	    /var/www/html/typo3conf/LocalConfiguration.php
+fi
+if [[ "${T3_REPLACE_ENCRYPTION_KEY}" ]]; then
+    key=$(hexdump -n 48 -e '4/4 "%08X" 1 "\n"' /dev/urandom)
+    key=$(echo "${key}" | tr '[:upper:]' '[:lower:]' | tr -d '[:space:]')
+    old_key=50c80989f47d1097a66ed9d584b935dca4ecf881ffaf814701572906cb6f0cd894d10da8859d1d9b2241e0fe0fb2692d
+    docker exec ${T3_CONTAINER} sed -i -e "s/${old_key}/${key}/g" /var/www/html/typo3conf/LocalConfiguration.php
+fi
+
+### Deploy qfq extension to container ###
+
+# This is slow. Could also be done in docker image build process.
+# Or could mount qfq as a volume to the typo3-qfq container. (might cause problems)
+if ! [[ $1 == "-no-deploy" ]]; then
+    ./deploy_to_container.sh
+fi
+
+
+########################################
+##           Post Process             ##
+########################################
+
+### Set Typo3 Admin Pass ###
+
+if [[ "${T3_ADMINO_PASSWORD}" ]]; then
+    T3_ADMINO_PASSWORD_HASH=$(curl http://127.0.0.1:${T3_PORT}/typo3conf/ext/qfq/Source/api/hashPassword.php?pw=${T3_ADMINO_PASSWORD})
+	mysql -u root --password=${MYSQL_ROOT_PASSWORD} --port=${DB_PORT} -h 127.0.0.1 -D ${T3_DATABASE} \
+	    -e "UPDATE be_users SET password='${T3_ADMINO_PASSWORD_HASH}' WHERE username='admino';"
+fi
+
+
+########################################
+##           User Output              ##
+########################################
+
+echo "Finished. Go to:"
+echo "localhost:${T3_PORT}"
\ No newline at end of file

docker/run_selenium_tests_docker.sh

+#!/bin/bash -ex
+
+source _helper_functions.sh
+
+source run_qfq_docker.output
+
+SELENIUM_IMAGE=python-selenium
+
+makePathExecutable "${PWD}/../" # needed for volume mounting
+
+SELENIUM_CONTAINER=$(docker run \
+    --link ${T3_CONTAINER}:typo3container \
+    --volume="${PWD}/../":/workingdir \
+    --shm-size="2g" \
+    -e HOST_UID=${UID} \
+    ${SELENIUM_IMAGE} \
+    "cd /workingdir/extension/Tests/selenium; python -m unittest discover")

docker/run_selenium_tests_local.sh

+#!/bin/bash -ex
+
+source run_qfq_docker.output
+
+# download chromedriver
+if [ ! -f chromedriver ]; then
+    wget -O /tmp/chromedriver.zip http://chromedriver.storage.googleapis.com/`curl -sS chromedriver.storage.googleapis.com/LATEST_RELEASE`/chromedriver_linux64.zip
+    unzip /tmp/chromedriver.zip chromedriver
+    chmod +x chromedriver
+fi
+export CHROMEDRIVER_PATH="${PWD}/chromedriver"
+
+# run tests
+cd ../extension/Tests/selenium
+export SELENIUM_URL="http://127.0.0.1:${T3_PORT}"
+export SELENIUM_HEADLESS="no"
+python -m unittest discover
\ No newline at end of file

extension/Source/api/hashPassword.php

+<?php
+
+namespace qfq;
+
+use qfq;
+
+require_once(__DIR__ . '/../core/typo3/Password.php');
+
+echo Password::getHash($_GET["pw"]);
\ No newline at end of file

extension/Tests/selenium/qfqselenium.py

+# -*- coding: utf-8 -*-
+from selenium import webdriver
+from selenium.webdriver.chrome.options import Options
+from selenium.webdriver.support.ui import Select
+from selenium.common.exceptions import StaleElementReferenceException, NoSuchElementException, WebDriverException
+import unittest
+import os
+import sys
+import time
+import codecs
+import re
+import socket
+
+
+def urlJoin(url_list):
+	return '/'.join(s.strip('/') for s in url_list)
+
+def urlFromHostname(hostname, port=80):
+	try:
+		return 'http://' + socket.gethostbyname(hostname) + ':' + str(port)
+	except socket.gaierror as e:
+		return 'unknown'
+
+class QfqSeleniumTestCase(unittest.TestCase):
+    """initialize selenium and add custom commands and asserts"""
+    max_number_of_log_files_to_keep = 100
+
+    # These variables can be overwritten by environment variables of the same name
+    CHROMEDRIVER_PATH = "chromedriver"
+    SELENIUM_LOGS_PATH = os.getcwd()
+    SELENIUM_HEADLESS = 'yes'   # set environment variable to 'no' to turn off
+    SELENIUM_URL = urlFromHostname('typo3container')
+
+    @classmethod
+    def setUpClass(cls):
+        """executed by unittest once before any tests are executed"""
+
+        # read environment variables
+        cls.CHROMEDRIVER_PATH = os.environ.get('CHROMEDRIVER_PATH', cls.CHROMEDRIVER_PATH)
+        cls.SELENIUM_LOGS_PATH = os.environ.get('SELENIUM_LOGS_PATH', cls.SELENIUM_LOGS_PATH)
+        cls.SELENIUM_HEADLESS = os.environ.get('SELENIUM_HEADLESS', cls.SELENIUM_HEADLESS)
+        cls.SELENIUM_URL = os.environ.get('SELENIUM_URL', cls.SELENIUM_URL)
+
+        # setup log directory, delete very old log files
+        cls.selenium_logs_dir = 'selenium_logs'
+        cls.selenium_logs_dir_path = os.path.join(cls.SELENIUM_LOGS_PATH, cls.selenium_logs_dir)
+        if not os.path.exists(cls.selenium_logs_dir_path):
+            os.makedirs(cls.selenium_logs_dir_path)
+        existing_log_files = os.listdir(cls.selenium_logs_dir_path)
+        existing_log_files.sort()
+        log_files_to_delete = existing_log_files[:-cls.max_number_of_log_files_to_keep]
+        log_file_pattern = re.compile('[0-9]{8}-{1}[0-9]{6}.*')
+        for filename in log_files_to_delete:
+            if not log_file_pattern.match(filename):
+                print 'non log file in log directory found: ', filename
+                continue
+            file_path = os.path.join(cls.selenium_logs_dir_path, filename)
+            os.remove(file_path)
+
+        # initialize webdriver
+        chrome_options = Options()
+        if  cls.SELENIUM_HEADLESS != 'no':
+            chrome_options.add_argument("--headless")
+        chrome_options.add_argument("--window-size=1920,1080")
+        chrome_options.add_argument("--disable-dev-shm-usage")
+        chrome_options.add_argument("--no-sandbox")
+        desired_capabilities = {'UNEXPECTED_ALERT_BEHAVIOUR': 'ignore'}
+        cls.driver = webdriver.Chrome(chrome_options=chrome_options, 
+            executable_path=cls.CHROMEDRIVER_PATH, 
+            desired_capabilities=desired_capabilities)
+        cls.driver.implicitly_wait(30)
+
+    @classmethod
+    def tearDownClass(cls):
+        """executed by unittest after all test cases were executed"""
+        cls.driver.quit()
+        
+    def tearDown(self):
+        """executed by unittest after every single test case"""
+
+        # save website state on failure
+        if sys.exc_info()[0]:
+            filename = time.strftime("%Y%m%d-%H%M%S") + '_' + self._testMethodName
+            screenshot_file_path = self.qfq_save_screenshot(filename)
+            html_file_path = self.qfq_save_html(filename)
+            print 'Test failed.'
+            print 'Webpage screenshot saved to ' + screenshot_file_path
+            print 'Webpage Html saved to ' + html_file_path
+            print '!!! ATTENTION !!!: If you get the error "unexpected alert open",' \
+                + 'there must be another error above which actually triggers the test failure.'
+
+    def _prepare_log_file_path(self, filename, suffix=''):
+        file_path = os.path.join(self.selenium_logs_dir_path, filename + suffix)
+        return file_path
+
+    def _retry_on_certain_exceptions(self, function, retries=10):
+        while retries >= 0:
+            try:
+                function()
+                break
+            except (StaleElementReferenceException, NoSuchElementException, WebDriverException):
+                retries -= 1
+
+    def qfq_save_screenshot(self, filename):
+