Firefox, snap, selenium = headaches

[gravitystorm]

Some personal notes:

andy@denali:~/src/openstreetmap-website$ git diff
diff --git a/test/application_system_test_case.rb b/test/application_system_test_case.rb
index d2c3d5196..2f20736a3 100644
--- a/test/application_system_test_case.rb
+++ b/test/application_system_test_case.rb
@@ -9,6 +9,8 @@ end
 class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
   driven_by :selenium, :using => :headless_firefox do |options|
     options.add_preference("intl.accept_languages", "en")
+    # git update-index --skip-worktree test/application_system_test_case.rb
+    options.binary = "/snap/firefox/current/usr/lib/firefox/firefox"
   end
 
   def before_setup
diff --git a/test/teaspoon_env.rb b/test/teaspoon_env.rb
index 8a9dc001f..9df7d04c0 100644
--- a/test/teaspoon_env.rb
+++ b/test/teaspoon_env.rb
@@ -103,7 +103,7 @@ Teaspoon.configure do |config|
   config.driver_options = {
     :client_driver => :firefox,
     :selenium_options => {
-      :options => Selenium::WebDriver::Firefox::Options.new(:args => ["-headless"])
+      :options => Selenium::WebDriver::Firefox::Options.new(:args => ["-headless"], :binary => "/snap/firefox/current/usr/lib/firefox/firefox")
     }
   }

TODO figure out why the JS doesn't work properly on most of the system tests - does the geckodriver need some kind of configuration override too?