Support Ruby 2.6 endless range syntax in Result#[]

lib/capybara/result.rb

@@ -59,7 +59,7 @@ module Capybara
           nil
         end
       when Range
-        idx.max
+        idx.end && idx.max # endless range will have end == nil
       end
 
       if max_idx.nil?

spec/result_spec.rb

@@ -72,6 +72,12 @@ RSpec.describe Capybara::Result do
     expect(result[-1].text).to eq 'Delta'
     expect(result[-2, 3].map(&:text)).to eq %w[Gamma Delta]
     expect(result[1..7].map(&:text)).to eq %w[Beta Gamma Delta]
+    expect(result[1...3].map(&:text)).to eq %w[Beta Gamma]
+    expect(result[2..-1].map(&:text)).to eq %w[Gamma Delta]
+    expect(result[2...-1].map(&:text)).to eq %w[Gamma]
+    eval <<~TEST if RUBY_VERSION.to_f > 2.5
+      expect(result[2..].map(&:text)).to eq %w[Gamma Delta]
+    TEST
   end
 
   it 'works with filter blocks' do