Delegate properly to custom Resolver instances

Introduce `EmptyTemplateResolverBuilder` for building instances of either
`EmptyTemplateResolverProxy` or `EmptyTemplateFileSystemResolver`, depending on
whether the given path is already an `ActionView::Resolver` instance or not.

The new `EmptyTemplateResolverProxy` class simply delegates all method calls to
the resolver that it was instantiated with, except for `#find_templates` which
it overrides to return templates that renders with `EmptyTemplateHandler`.

Author: bquorning

lib/rspec/rails/view_rendering.rb

@@ -39,18 +39,50 @@ def render_views?
         self.class.render_views? || !controller.class.respond_to?(:view_paths)
       end
 
-      # Delegates find_all to the submitted path set and then returns templates
-      # with modified source
-      #
-      # @private
-      class EmptyTemplateResolver < ::ActionView::FileSystemResolver
+      class EmptyTemplateResolverBuilder
+        def initialize(path)
+          @path = path
+        end
 
-        def initialize(path, pattern=nil)
-          unless path.is_a?(::ActionView::Resolver)
-            super
+        def resolver
+          if @path.is_a?(::ActionView::Resolver)
+            EmptyTemplateResolverProxy.new(@path)
+          else
+            EmptyTemplateFileSystemResolver.new(@path)
           end
         end
+      end
 
+      class EmptyTemplateResolverProxy
+        def initialize(resolver)
+          @resolver = resolver
+        end
+
+        def method_missing(name, *args, &block)
+          @resolver.send(name, *args, &block)
+        end
+
+      private
+
+        def find_templates(*args)
+          templates = @resolver.find_templates(*args)
+          templates.map do |template|
+            ::ActionView::Template.new(
+              "",
+              template.identifier,
+              EmptyTemplateHandler,
+              :virtual_path => template.virtual_path,
+              :format => template.formats
+            )
+          end
+        end
+      end
+
+      # Delegates find_all to the submitted path set and then returns templates
+      # with modified source
+      #
+      # @private
+      class EmptyTemplateFileSystemResolver < ::ActionView::FileSystemResolver
       private
 
         def find_templates(*args)
@@ -88,13 +120,13 @@ def append_view_path(new_path)
       private
 
         def _path_decorator(*paths)
-          paths.map { |path| EmptyTemplateResolver.new(path) }
+          paths.map { |path| EmptyTemplateResolverBuilder.new(path).resolver }
         end
       end
 
       # @private
       RESOLVER_CACHE = Hash.new do |hash, path|
-        hash[path] = EmptyTemplateResolver.new(path)
+        hash[path] = EmptyTemplateResolverBuilder.new(path).resolver
       end
 
       included do