Added a test for MissingTemplate change, and changed to use Array.wrap() as

requested by josevalim.

actionpack/lib/action_view/path_set.rb

@@ -15,7 +15,7 @@ module ActionView #:nodoc:
     end
 
     def find_all(path, prefixes = [], *args)
-      prefixes = [prefixes] if String === prefixes
+      prefixes = Array.wrap(prefixes) if String === prefixes
       prefixes.each do |prefix|
         each do |resolver|
           templates = resolver.find_all(path, prefix, *args)

actionpack/lib/action_view/template/error.rb

@@ -29,7 +29,7 @@ module ActionView
 
     def initialize(paths, path, prefixes, partial, details, *)
       @path = path
-      prefixes = [prefixes] if String === prefixes
+      prefixes = Array.wrap(prefixes) if String === prefixes
       display_paths = paths.compact.map{ |p| p.to_s.inspect }.join(", ")
       template_type = if partial
         "partial"

actionpack/test/template/lookup_context_test.rb

@@ -251,4 +251,13 @@ class TestMissingTemplate < ActiveSupport::TestCase
     end
     assert_match %r{Missing partial parent/foo, child/foo with .* Searched in:\n  \* "/Path/to/views"\n}, e.message
   end
+
+  test "if a single prefix is passed as a string and the lookup fails, MissingTemplate accepts it" do
+    e = assert_raise ActionView::MissingTemplate do
+      details = {:handlers=>[], :formats=>[], :locale=>[]}
+      @lookup_context.view_paths.find("foo", "parent", true, details)
+    end
+    assert_match %r{Missing partial parent/foo with .* Searched in:\n  \* "/Path/to/views"\n}, e.message
+  end 
+  
 end