Add custom matcher method for RSpec

lib/kookaburra/test_helpers.rb

@@ -1,4 +1,5 @@
 require 'kookaburra'
+require 'kookaburra/mental_model_matcher'
 require 'active_support/core_ext/module/delegation'
 
 class Kookaburra
@@ -96,5 +97,12 @@ def k
     # @method ui
     # Delegates to {#k}
     delegate :ui, :to => :k
+
+    # RSpec-style custom matcher that compares a given array with
+    # the current state of one named collection in the mental model
+    def match_mental_model_of(collection_key)
+      mental_model = Kookaburra.configuration.mental_model # naughty
+      MentalModel::Matcher.new(mental_model, collection_key)
+    end
   end
 end

spec/kookaburra/test_helpers_spec.rb

@@ -39,4 +39,25 @@
       ui
     end
   end
+
+  describe "#match_mental_model_of" do
+    let(:mm) { Kookaburra.configuration.mental_model }
+
+    def sanity_check
+      match_mental_model_of(:widgets).should be_kind_of(Kookaburra::MentalModel::Matcher)
+    end
+
+    before(:each) do
+      sanity_check
+      mm.widgets[:foo] = 'FOO'
+    end
+
+    it "does a positive match" do
+      ['FOO'].should match_mental_model_of(:widgets)
+    end
+
+    it "does a negative match" do
+      ['BAR'].should_not match_mental_model_of(:widgets)
+    end
+  end
 end