Only return spec paths that are in spec directories

Currently (in sprockets 3), Konacha.spec_paths returns all
specs found in any rails asset path, not just those within
the spec_dir

lib/konacha.rb

@@ -48,7 +48,8 @@ def spec_paths
         elsif Rails.application.assets.respond_to?(:each_file)
           paths = Rails.application.assets.each_file.find_all { |path|
             pathname = Pathname.new(path)
-            config.spec_matcher === pathname.basename.to_s &&
+            pathname.dirname.to_s.start_with?(root) &&
+              config.spec_matcher === pathname.basename.to_s &&
               (pathname.extname == '.js' || Tilt[pathname])
           }
         else

spec/konacha_spec.rb

@@ -99,17 +99,19 @@ def self.===(path)
       end
     end
 
-    context 'with additional spec directories' do
+    context 'with configured spec directories' do
       around do |example|
         begin
           spec_dir = Konacha.config.spec_dir
           Konacha.configure {|c| c.spec_dir = ["spec/javascripts", "app/sections"]}
           # For Sprockets 3, adding to config.assets.paths does not work
           if Rails.application.assets.respond_to?(:append_path)
             Rails.application.assets.append_path(Rails.root.join("app/sections").to_s)
+            Rails.application.assets.append_path(Rails.root.join("spec/isolated").to_s)
           # Sprockets 2
           else
             Rails.application.config.assets.paths << Rails.root.join("app/sections").to_s
+            Rails.application.config.assets.paths << Rails.root.join("spec/isolated").to_s
           end
           example.run
         ensure
@@ -127,6 +129,16 @@ def self.===(path)
         Konacha.spec_root.should include Rails.root.join("app/sections").to_s
         subject.should include("my_section/my_section_spec.js.coffee")
       end
+
+      # spec/isolated is in the assets path, but not Koncha's spec_dir
+      it 'does not have specs from spec/isolated' do
+        Konacha.spec_root.should_not include Rails.root.join("spec/isolated").to_s
+
+        spec_file = "isolated/errors/failing_iframe_spec.js.coffee"
+        # Ensure neither the relative or absolute paths are present
+        subject.should_not include(spec_file)
+        subject.should_not include(Rails.root.join("spec", spec_file).to_s)
+      end
     end
 
   end