Detect when tests are defined

Library/Homebrew/cmd/test.rb

@@ -17,7 +17,7 @@ module Homebrew extend self
       end
 
       # Cannot test formulae without a test method
-      unless f.respond_to? :test
+      unless f.test_defined?
         ofail "#{f.name} defines no test"
         next
       end

Library/Homebrew/formula.rb

@@ -26,6 +26,7 @@ class Formula
     set_instance_variable :bottle
     set_instance_variable :devel
     set_instance_variable :head
+    set_instance_variable :test
 
     @name = name
     validate_variable :name
@@ -590,12 +591,16 @@ public
     ret = nil
     mktemp do
       @testpath = Pathname.pwd
-      ret = instance_eval(&self.class.test)
+      ret = instance_eval(&@test)
       @testpath = nil
     end
     ret
   end
 
+  def test_defined?
+    not @test.nil?
+  end
+
 private
 
   def stage
@@ -642,7 +647,12 @@ private
   end
 
   def self.method_added method
-    raise 'You cannot override Formula.brew' if method == :brew
+    case method
+    when :brew
+      raise "You cannot override Formula#brew"
+    when :test
+      @test = method
+    end
   end
 
   class << self