Do not auto-submit forms if they have multiple inputs (#2696)

lib/capybara/rack_test/node.rb

@@ -225,7 +225,7 @@ def set_input(value) # rubocop:disable Naming/AccessorMethodName
       native.remove
     else
       value.to_s.tap do |set_value|
-        if set_value.end_with?("\n") && form&.css('input, textarea')&.count
+        if set_value.end_with?("\n") && form&.css('input, textarea')&.count == 1
           native['value'] = set_value.to_s.chop
           Capybara::RackTest::Form.new(driver, form).submit(self)
         else

lib/capybara/spec/session/node_spec.rb

@@ -163,6 +163,12 @@
       @session.find(:css, '#single_input').set("my entry\n")
       expect(extract_results(@session)['single_input']).to eq('my entry')
     end
+
+    it 'should not submit single text input forms if ended with \n and has multiple values' do
+      @session.visit('/form')
+      @session.find(:css, '#two_input_1').set("my entry\n")
+      expect(@session.find(:css, '#two_input_1').value).to eq("my entry\n")
+    end
   end
 
   describe '#tag_name' do

lib/capybara/spec/views/form.erb

@@ -699,6 +699,11 @@ New line after and before textarea tag
   <input type="text" name="form[single_input]" id="single_input"/>
 </form>
 
+<form id="two_input_form" action="/form" method="post">
+  <input type="text" name="form[two_input_1]" id="two_input_1"/>
+  <input type="text" name="form[two_input_2]" id="two_input_2"/>
+</form>
+
 <label>Confusion
   <input type="checkbox" id="confusion_checkbox" class="confusion-checkbox confusion"/>
 </label>