Use capybara-webmock to avoid external requests

The images from OpenStreetMap take a while to load, sometimes even
causing Net::ReadTimeout errors if the internet connection is slow. It's
happened a lot recently on Travis builds.

Using capybara-webmock we guarantee the test suite doesn't fail due to
network issues.

Gemfile

@@ -82,6 +82,7 @@ end
 
 group :test do
   gem "capybara", "~> 2.17.0"
+  gem "capybara-webmock", "~> 0.5.3"
   gem "coveralls", "~> 0.8.22", require: false
   gem "database_cleaner", "~> 1.7.0"
   gem "email_spec", "~> 2.1.0"

Gemfile.lock

@@ -123,6 +123,11 @@ GEM
       rack (>= 1.0.0)
       rack-test (>= 0.5.4)
       xpath (>= 2.0, < 4.0)
+    capybara-webmock (0.5.3)
+      capybara (>= 2.4, < 4)
+      rack (>= 1.4)
+      rack-proxy (>= 0.6.0)
+      selenium-webdriver (~> 3.0)
     childprocess (0.9.0)
       ffi (~> 1.0, >= 1.0.11)
     chronic (0.10.2)
@@ -389,6 +394,8 @@ GEM
       rack (>= 0.4)
     rack-attack (5.0.1)
       rack
+    rack-proxy (0.6.5)
+      rack
     rack-test (0.6.3)
       rack (>= 1.0)
     rails (5.0.7.2)
@@ -584,6 +591,7 @@ DEPENDENCIES
   capistrano-rails (~> 1.4.0)
   capistrano3-delayed-job (~> 1.7.3)
   capybara (~> 2.17.0)
+  capybara-webmock (~> 0.5.3)
   ckeditor (~> 4.2.3)
   cocoon (~> 1.2.9)
   coffee-rails (~> 4.2.2)

spec/rails_helper.rb

@@ -33,7 +33,9 @@ end
 
 Capybara.register_driver :headless_chrome do |app|
   capabilities = Selenium::WebDriver::Remote::Capabilities.chrome(
-    chromeOptions: { args: %w(headless no-sandbox window-size=1200,600) }
+    chromeOptions: {
+      args: %W[headless no-sandbox window-size=1200,600 proxy-server=127.0.0.1:#{Capybara::Webmock.port_number}]
+    }
   )
 
   Capybara::Selenium::Driver.new(

spec/spec_helper.rb

@@ -65,6 +65,14 @@ RSpec.configure do |config|
     end
   end
 
+  config.before(:each, type: :feature) do
+    Capybara::Webmock.start
+  end
+
+  config.after(:suite) do
+    Capybara::Webmock.stop
+  end
+
   config.after(:each, :page_driver) do
     page.driver.reset!
   end