Add error description for style filter

lib/capybara/queries/selector_query.rb

@@ -50,6 +50,15 @@ module Capybara
         end
         desc << " with id #{options[:id]}" if options[:id]
         desc << " with classes [#{Array(options[:class]).join(',')}]" if options[:class]
+        desc << case options[:style]
+        when String
+          " with style attribute #{options[:style].inspect}"
+        when Regexp
+          " with style attribute matching #{options[:style].inspect}"
+        when Hash
+          " with styles #{options[:style].inspect}"
+        else ''
+        end
         desc << selector.description(node_filters: show_for[:node], **options)
         desc << ' that also matches the custom filter block' if @filter_block && show_for[:node]
         desc << " within #{@resolved_node.inspect}" if describe_within?

lib/capybara/spec/session/has_css_spec.rb

@@ -41,14 +41,26 @@ Capybara::SpecHelper.spec '#has_css?' do
   context ':style option' do
     it 'should support String' do
       expect(@session).to have_css('p', style: 'line-height: 25px;')
+
+      expect do
+        expect(@session).to have_css('p', style: 'display: not_valid')
+      end.to raise_error(RSpec::Expectations::ExpectationNotMetError, /style attribute "display: not_valid"/)
     end
 
     it 'should support Regexp' do
       expect(@session).to have_css('p', style: /-height: 2/)
+
+      expect do
+        expect(@session).to have_css('p', style: /not_valid/)
+      end.to raise_error(RSpec::Expectations::ExpectationNotMetError, %r{style attribute matching /not_valid/})
     end
 
     it 'should support Hash', requires: [:css] do
       expect(@session).to have_css('p', style: { 'line-height': '25px' })
+
+      expect do
+        expect(@session).to have_css('p', style: { 'line-height': '30px' })
+      end.to raise_error(RSpec::Expectations::ExpectationNotMetError, /with styles \{:"line-height"=>"30px"\}/)
     end
   end