Add firefox date/time inputs being set via string tests

lib/capybara/selenium/node.rb

@@ -398,7 +398,7 @@ private
     end
 
     def to_date_str
-      value.to_date.strftime('%Y-%m-%d')
+      value.to_date.iso8601
     end
 
     def timeable?

spec/selenium_spec_firefox.rb

@@ -73,6 +73,35 @@ RSpec.describe 'Capybara::Session with firefox' do # rubocop:disable RSpec/Multi
   include Capybara::SpecHelper
   include_examples  'Capybara::Session', TestSessions::SeleniumFirefox, :selenium_firefox
   include_examples  Capybara::RSpecMatchers, TestSessions::SeleniumFirefox, :selenium_firefox
+
+  describe 'filling in Firefox-specific date and time fields with keystrokes' do
+    let(:datetime) { Time.new(1983, 6, 19, 6, 30) }
+    let(:session) { TestSessions::SeleniumFirefox }
+
+    before do
+      session.visit('/form')
+    end
+
+    it 'should fill in a date input with a String' do
+      session.fill_in('form_date', with: datetime.to_date.iso8601)
+      session.click_button('awesome')
+      expect(Date.parse(extract_results(session)['date'])).to eq datetime.to_date
+    end
+
+    it 'should fill in a time input with a String' do
+      session.fill_in('form_time', with: datetime.to_time.strftime('%T'))
+      session.click_button('awesome')
+      results = extract_results(session)['time']
+      expect(Time.parse(results).strftime('%r')).to eq datetime.strftime('%r')
+    end
+
+    it 'should fill in a datetime input with a String' do
+      # FF doesn't currently support datetime-local so this is really just a text input
+      session.fill_in('form_datetime', with: datetime.iso8601)
+      session.click_button('awesome')
+      expect(Time.parse(extract_results(session)['datetime'])).to eq datetime
+    end
+  end
 end
 
 RSpec.describe Capybara::Selenium::Driver do