Don't create Caskroom.path for tests.

Library/Homebrew/cask/lib/hbc/caskroom.rb

@@ -9,10 +9,12 @@ module Hbc
     def ensure_caskroom_exists
       return if path.exist?
 
-      ohai "Creating Caskroom at #{path}" if $stdout.tty?
       sudo = !path.parent.writable?
 
-      ohai "We'll set permissions properly so we won't need sudo in the future" if $stdout.tty? && sudo
+      if sudo && !ENV.key?("SUDO_ASKPASS") && $stdout.tty?
+        ohai "Creating Caskroom at #{path}"
+        ohai "We'll set permissions properly so we won't need sudo in the future."
+      end
 
       SystemCommand.run("/bin/mkdir", args: ["-p", path], sudo: sudo)
       SystemCommand.run("/bin/chmod", args: ["g+rwx", path], sudo: sudo)

Library/Homebrew/cask/lib/hbc/cli/doctor.rb

@@ -62,9 +62,7 @@ module Hbc
 
         path = Pathname.new(user_tilde(Caskroom.path.to_s))
 
-        if !path.exist?
+        if path.exist? && !path.writable?
-          add_error "The staging path #{path} does not exist."
-        elsif !path.writable?
           add_error "The staging path #{path} is not writable by the current user."
         end
 

Library/Homebrew/test/support/helper/spec/shared_context/homebrew_cask.rb

@@ -23,7 +23,7 @@ RSpec.shared_context "Homebrew-Cask" do
     begin
       HOMEBREW_CASK_DIRS.values.each(&:mkpath)
 
-      [Hbc::Config.global.binarydir, Hbc::Caskroom.path].each(&:mkpath)
+      [Hbc::Config.global.binarydir].each(&:mkpath)
 
       Tap.default_cask_tap.tap do |tap|
         FileUtils.mkdir_p tap.path.dirname