Run Safari Technology Preview tests on Travis

.rspec

@@ -1,2 +1,5 @@
 --color
---order random
+--order random
+--require rspec/instafail
+--format RSpec::Instafail
+--format progress

.travis.yml

@@ -93,7 +93,20 @@ matrix:
       env: W3C=true HEADLESS=true
       addons:
         chrome: beta
+    - gemfile: Gemfile
+      os: osx
+      osx_image: xcode10.2
+      rvm: 2.6
+      addons:
+        homebrew:
+          taps: homebrew/cask-versions
+          casks: safari-technology-preview
+      before_script:
+        - "sudo /usr/bin/safaridriver --enable"
+        - "sudo '/Applications/Safari Technology Preview.app/Contents/MacOS/safaridriver' --enable"
+      script: "bundle exec rake spec_safari"
   allow_failures:
+    - os: osx
     - gemfile: gemfiles/Gemfile.beta-versions
     - gemfile: gemfiles/Gemfile.edge-firefox
     - env: W3C=true HEADLESS=true

capybara.gemspec

@@ -45,6 +45,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency('puma')
   s.add_development_dependency('rake')
   s.add_development_dependency('rspec', ['>= 3.5.0'])
+  s.add_development_dependency('rspec-instafail')
   s.add_development_dependency('rubocop')
   s.add_development_dependency('rubocop-performance')
   s.add_development_dependency('rubocop-rspec')

spec/spec_helper.rb

@@ -64,7 +64,7 @@ module Capybara
       mod = mod::Service if ::Selenium::WebDriver::Service.respond_to? :driver_path
       path = mod.driver_path
       path = path.call if path.respond_to? :call
-      $stdout.puts `#{path} --version`
+      $stdout.puts `#{path.gsub(' ', '\ ')} --version`
     end
   end
 end