had this error
" test login --core test (Devato.Features.IndexPageTest)
test/devato_web/features/index_page_test.exs:13
** (RuntimeError) Wallaby had an internal issue with HTTPoison:
%HTTPoison.Error{id: nil, reason: :timeout}
stacktrace:
(wallaby 0.23.0) lib/wallaby/httpclient.ex:37: Wallaby.HTTPClient.make_request/5
(wallaby 0.23.0) lib/wallaby/experimental/chrome.ex:96: Wallaby.Experimental.Chrome.start_session/1
(wallaby 0.23.0) lib/wallaby.ex:78: Wallaby.start_session/1
(devato 0.1.0) test/support/feature_case.ex:25: Devato.FeatureCase.__ex_unit_setup_0/1
(devato 0.1.0) test/support/feature_case.ex:1: Devato.FeatureCase.ex_unit/2
test/devato_web/features/index_page_test.exs:1: Devato.Features.IndexPageTest.ex_unit/2"

i could run the tests chrome headless but i needed it to work so i can see it running on the browser . What worked for me was configuring the timeouts

added
config :wallaby,
hackney_options: [timeout: :infinity, recv_timeout: :infinity]

Overriding a value

config :wallaby,
hackney_options: [timeout: 5_000]

hope this helps others