Preload browser driver_path for system testing

The webdrivers gem configures Selenium::WebDriver::Service.driver_path
as a proc which updates the web drivers and returns their path.

This commit introduces SystemTesting::Browser#preload, which runs this
proc early. This ensures that webdrivers update is run before forking
for parallel testing, but doesn't explicitly tie us to that gem (and I
think anything configured as driver_path probably makes sense to
eager-load).

1 files changed, 13 insertions, 0 deletions

diff --git a/actionpack/test/dispatch/system_testing/driver_test.rb b/actionpack/test/dispatch/system_testing/driver_test.rb
index 7ef306d04b..d3b16d0328 100644
--- a/actionpack/test/dispatch/system_testing/driver_test.rb
+++ b/actionpack/test/dispatch/system_testing/driver_test.rb
@@ -120,4 +120,17 @@ class DriverTest < ActiveSupport::TestCase
       driver.use
     end
   end
+
+  test "preloads browser's driver_path" do
+    called = false
+
+    original_driver_path = ::Selenium::WebDriver::Chrome::Service.driver_path
+    ::Selenium::WebDriver::Chrome::Service.driver_path = -> { called = true }
+
+    ActionDispatch::SystemTesting::Driver.new(:selenium, screen_size: [1400, 1400], using: :chrome)
+
+    assert called
+  ensure
+    ::Selenium::WebDriver::Chrome::Service.driver_path = original_driver_path
+  end
 end