fix uninstall to work with multiple casks at once

homebrew does internal caching in ARGV that prevents us from doing the
`ARGV.clear; ARGV << 'newarg'` trick twice.

rather than try to further reach in to homebrew's innards, i figure it's
better to just pass multiple arguments down to homebrew code at once,
since it already supports that

refs #47

lib/cask.rb

@@ -65,10 +65,7 @@ class Cask
   end
 
   def installed?
-    return false unless destination_path.exist?
-    destination_path.entries.any? do |f|
-      f.basename.to_s =~ /.app$/
-    end
+    destination_path.exist?
   end
 
   def to_s

lib/cask/cli/uninstall.rb

@@ -1,12 +1,10 @@
 class Cask::CLI::Uninstall
   def self.run(*cask_names)
-    cask_names.each do |cask_name|
-      begin
-       cask = Cask.load(cask_name)
-       Cask::Installer.uninstall(cask)
-      rescue CaskUnavailableError,CaskNotInstalledError => e
-        onoe e
-      end
+    begin
+      casks = cask_names.map { |cn| Cask.load(cn) }
+      Cask::Installer.uninstall(*casks)
+    rescue CaskUnavailableError,CaskNotInstalledError => e
+      onoe e
     end
   end
 

lib/cask/installer.rb

@@ -14,12 +14,16 @@ class Cask::Installer
       ohai "Success! #{cask} installed to #{cask.destination_path}"
     end
 
-    def uninstall(cask)
-      raise CaskNotInstalledError.new(cask) unless cask.installed?
+    def uninstall(*casks)
+      casks.each do |cask|
+        raise CaskNotInstalledError.new(cask) unless cask.installed?
+      end
 
       require 'cmd/uninstall'
       ARGV.clear
-      ARGV << cask.title
+      casks.each do |cask|
+        ARGV << cask.title
+      end
       Homebrew.uninstall
     end
 

test/cli/uninstall_test.rb

@@ -23,4 +23,21 @@ describe Cask::CLI::Uninstall do
     Cask::Installer.expects(:uninstall).with(fake_cask)
     Cask::CLI::Uninstall.run('fake-cask')
   end 
+
+  it "can uninstall multiple casks at once" do
+    caffeine = Cask.load('caffeine')
+    anvil = Cask.load('anvil')
+
+    shutup do
+      Cask::Installer.install(caffeine)
+      Cask::Installer.install(anvil)
+    end
+
+    shutup do
+      Cask::CLI::Uninstall.run('caffeine', 'anvil')
+    end
+
+    caffeine.wont_be :installed?
+    anvil.wont_be :installed?
+  end
 end