allow additional arguments for be_able_to matcher, this requires Ruby 1.8.7 or higher to use matcher

CHANGELOG.rdoc

@@ -1,5 +1,7 @@
 1.1.0 (not released)
 
+* Adding be_able_to RSpec matcher (thanks dchelimsky) - see issue #54
+
 * Support additional arguments to can? which get passed to the block - see issue #48
 
 

lib/cancan/matchers.rb

@@ -1,13 +1,13 @@
-Spec::Matchers.define :be_able_to do |action, subject|
+Spec::Matchers.define :be_able_to do |*args|
   match do |model|
-    model.can?(action, subject)
+    model.can?(*args)
   end
 
   failure_message_for_should do |model|
-    "expected to be able to #{action.inspect} #{subject.inspect}"
+    "expected to be able to #{args.map(&:inspect).join(" ")}"
   end
 
   failure_message_for_should_not do |model|
-    "expected not to be able to #{action.inspect} #{subject.inspect}"
+    "expected not to be able to #{args.map(&:inspect).join(" ")}"
   end
 end

spec/cancan/matchers_spec.rb

@@ -22,4 +22,12 @@ describe "be_able_to" do
       object.should_not be_able_to(:read, 123)
     end.should raise_error('expected not to be able to :read 123')
   end
+
+  it "delegates additional arguments to can? and reports in failure message" do
+    object = Object.new
+    mock(object).can?(:read, 123, 456) { false }
+    expect do
+      object.should be_able_to(:read, 123, 456)
+    end.should raise_error('expected to be able to :read 123 456')
+  end
 end