Fix CSS based default expression filters

lib/capybara/selector/selector.rb

@@ -251,7 +251,7 @@ module Capybara
     def css(*allowed_filters, &block)
       if block
         @format, @expression = :css, block
-        allowed_filters.flatten.each { |ef| expression_filters[ef] = nil }
+        allowed_filters.flatten.each { |ef| expression_filters[ef] = Filters::IdentityExpressionFilter.new(ef) }
       end
       format == :css ? @expression : nil
     end

spec/selector_spec.rb

@@ -54,7 +54,23 @@ RSpec.describe Capybara do
       end
 
       Capybara.add_selector :custom_css_selector do
-        css { |selector| selector }
+        css(:name) do |selector, name: nil, **|
+          selector ||= ''
+          selector += "[name='#{name}']" if name
+          selector
+        end
+
+        expression_filter(:placeholder) do |expr, val|
+          expr + "[placeholder='#{val}']"
+        end
+
+        expression_filter(:value) do |expr, val|
+          expr + "[value='#{val}']"
+        end
+
+        expression_filter(:title) do |expr, val|
+          expr + "[title='#{val}']"
+        end
       end
 
       Capybara.add_selector :custom_xpath_selector do
@@ -104,6 +120,19 @@ RSpec.describe Capybara do
       end
     end
 
+    describe 'css based selectors' do
+      it "supports filters specified in 'css' definition" do
+        expect(string).to have_selector(:custom_css_selector, 'input', name: 'form[my_text_input]')
+        expect(string).to have_no_selector(:custom_css_selector, 'input', name: 'form[not_my_text_input]')
+      end
+
+      it 'supports explicitly defined expression filters' do
+        expect(string).to have_selector(:custom_css_selector, placeholder: 'my text')
+        expect(string).to have_no_selector(:custom_css_selector, placeholder: 'not my text')
+        expect(string).to have_selector(:custom_css_selector, value: 'click me', title: 'submit button')
+      end
+    end
+
     describe 'builtin selectors' do
       context 'when locator is nil' do
         it 'devolves to just finding element types' do