fix: ignore empty or nil keys in Node#send_keys

Ferrum raises ArgumentError on empty or nil keys, so
`send_keys("")` or `send_keys(nil)` crashes under Cuprite while the
Selenium and rack_test drivers treat them as a no-op. Reject empty and
nil entries before delegating to Ferrum so otherwise portable Capybara
code stays driver-agnostic.

Author: myabc

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 ### Fixed
 - Ensure node has focus before setting value [#280]
+- `Capybara::Cuprite::Node#send_keys` ignores empty or nil keys instead of raising, matching the Selenium and rack_test drivers
 
 ### Removed
 

lib/capybara/cuprite/node.rb

@@ -220,6 +220,12 @@ def ==(other)
       end
 
       def send_keys(*keys)
+        # Match the Selenium/rack_test drivers: empty or nil keys are a no-op.
+        # Ferrum raises on them, which would break otherwise portable Capybara
+        # code such as `send_keys(value)` where `value` may be "".
+        keys = keys.reject { |key| key.nil? || key == "" }
+        return if keys.empty?
+
         command(:send_keys, keys)
       end
       alias send_key send_keys

spec/features/driver_spec.rb

@@ -1272,6 +1272,15 @@ def create_screenshot(file, *args)
           expect(input.value).to eq("Text appended")
         end
 
+        it "ignores empty or nil keys instead of raising" do
+          input = @session.find(:css, "#filled_input")
+
+          expect { input.native.send_keys("") }.not_to raise_error
+          expect { input.native.send_keys(nil) }.not_to raise_error
+
+          expect(input.value).to eq("Text")
+        end
+
         it "sends keys to empty textarea" do
           input = @session.find(:css, "#empty_textarea")