brew-cask-tests: import Rakefile logic.

This avoids a `rake` dependency in the Gemfile and an unnecessary shell
out.

Library/Homebrew/cask/Rakefile

@@ -1,17 +0,0 @@
-require "rake/testtask"
-require "rspec/core/rake_task"
-
-$LOAD_PATH.unshift(File.expand_path("#{ENV["HOMEBREW_REPOSITORY"]}/Library/Homebrew"))
-$LOAD_PATH.unshift(File.expand_path("../lib", __FILE__))
-
-namespace :test do
-  namespace :coverage do
-    desc "Upload coverage to Codecov"
-    task :upload do
-      require "simplecov"
-      require "codecov"
-      formatter = SimpleCov::Formatter::Codecov.new
-      formatter.format(SimpleCov::ResultMerger.merged_result)
-    end
-  end
-end

Library/Homebrew/cask/cmd/brew-cask-tests.rb

@@ -52,6 +52,9 @@ repo_root.cd do
 
   if upload_coverage
     puts "Submitting Codecov coverage..."
-    system "bundle", "exec", "rake", "test:coverage:upload"
+    require "simplecov"
+    require "codecov"
+    formatter = SimpleCov::Formatter::Codecov.new
+    formatter.format(SimpleCov::ResultMerger.merged_result)
   end
 end