Behat + Mink - Selenium2 issue: 'requiredCapabilities' parameter is not an object - selenium

Question

I am running tests using Behat, Mink and Selenium2.
I am running the example search-with-autocompletion test that employs the #javascript tag in a scenario.
This is the exception I get:
Behat\MinkExtension\Context\MinkContext::visit()
'requiredCapabilities' parameter is not an object
Build info: version: '3.5.3', revision: 'a88d25fe6b', time: '2017-08-29T12:54:15.039Z'
System info: host: '73b4ecff4d3d', ip: '172.17.0.2', os.name: 'Linux', os.arch: 'amd64', os.version: '3.19.0-32-generic', java.version: '1.8.0_131'
Driver info: driver.version: unknown
remote stacktrace: stack backtrace:
0: 0x5787ed - backtrace::backtrace::trace::h59229d13f6a8837d
1: 0x578942 - backtrace::capture::Backtrace::new::h23089c033eded8f0
2: 0x5068af - <webdriver::capabilities::LegacyNewSessionParameters as webdriver::command::Parameters>::from_json::hd98a6246b0731ef9
3: 0x506e44 - <webdriver::command::NewSessionParameters as webdriver::command::Parameters>::from_json::ha19e8e984af08954
4: 0x41f249 - <webdriver::command::WebDriverMessage<U>>::from_http::h239258e4ad67ac76
5: 0x43a64e - <webdriver::server::HttpHandler<U> as hyper::server::Handler>::handle::hd20f6e9e0a69e2b4
6: 0x42c9af - hyper::server::listener::spawn_with::{{closure}}::h8fa3cf343f537777
7: 0x4092d7 - std::panicking::try::do_call::h649be53a713433eb
8: 0x5dc20a - panic_unwind::__rust_maybe_catch_panic
at /checkout/src/libpanic_unwind/lib.rs:98
9: 0x41c43e - <F as alloc::boxed::FnBox<A>>::call_box::hf41feb3b2b67541e
10: 0x5d48a4 - alloc::boxed::{{impl}}::call_once<(),()>
at /checkout/src/liballoc/boxed.rs:650
- std::sys_common::thread::start_thread
at /checkout/src/libstd/sys_common/thread.rs:21
- std::sys::imp::thread::{{impl}}::new::thread_start
at /checkout/src/libstd/sys/unix/thread.rs:84
I am running Selenium2 standalone server v3.5.3 using docker-selenium and geckodriver v0.18.
My configuration for Behat:
default:
context:
class: 'FeatureContext'
extensions:
Behat\MinkExtension\Extension:
base_url: '<skipped>'
goutte:
guzzle_parameters:
curl.options:
CURLOPT_SSL_VERIFYPEER: false
CURLOPT_CERTINFO: false
CURLOPT_TIMEOUT: 120
ssl.certificate_authority: false
selenium2:
wd_host: "http://127.0.0.1:4444/wd/hub"
capabilities:
browser: firefox
# acceptSslCerts: true
# marionette: true
# No context:
no_context:
paths:
bootstrap: 'NON_EXISTING_FOLDER'
filters:
tags: '~#javascript'
# Context based on inheritance:
inheritance:
context:
class: 'InheritedFeatureContext'
# Context based on traits:
traits:
paths:
bootstrap: 'features/php54_bootstrap'
context:
class: 'TraitedFeatureContext'
# Context based on subcontexting:
subcontexts:
context:
class: 'SubcontextedFeatureContext'
If connecting to localhost:4444 I am able to create a session by hand.
If using python-selenium I am able to run this code:
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
driver = webdriver.Remote(
command_executor='http://127.0.0.1:4444/wd/hub',
desired_capabilities=DesiredCapabilities.FIREFOX
)
#driver = webdriver.Firefox()
driver.get("http://www.python.org")
assert "Python" in driver.title
elem = driver.find_element_by_name("q")
elem.clear()
elem.send_keys("pycon")
elem.send_keys(Keys.RETURN)
assert "No results found." not in driver.page_source
driver.close()
Thank you in advance folks.

Answer 1

Selenium 2 and Selenium 3 are not same. They are not 100% compatible. Selenium 3 is a step towards the W3C standard for Selenium.
From the exception it seems that Mink may not be compatible with Selenium 3. So either downgrade your Python selenium version to 2 (that again may not work because latest browsers may support only 3)
Also please look at https://github.com/minkphp/MinkSelenium2Driver/issues/254