Added TemplateError#backtrace that makes it much easier to debug template errors from unit and functional tests

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@145 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Added TemplateError#backtrace that makes it much easier to debug template errors from unit and functional tests
+
 * Added display of error messages with scaffolded form pages
 
 * Added option to ERB templates to swallow newlines by using <% if something -%> instead of just <% if something %>. Example:

actionpack/lib/action_view/template_error.rb

@@ -28,7 +28,7 @@ def sub_template_message
       end
     end
   
-    def source_extract
+    def source_extract(indention = 0)
       source_code = IO.readlines(@file_name)
       
       start_on_line = [ line_number - SOURCE_CODE_RADIUS - 1, 0 ].max
@@ -37,9 +37,9 @@ def source_extract
       line_counter = start_on_line
       extract = source_code[start_on_line..end_on_line].collect do |line| 
         line_counter += 1
-        "#{line_counter}: " + line
+        "#{' ' * indention}#{line_counter}: " + line
       end
-    
+
       extract.join
     end
   
@@ -71,6 +71,13 @@ def to_s
       "\n\n"
     end
 
+    def backtrace
+      [ 
+        "On line ##{line_number} of #{file_name}\n\n#{source_extract(4)}\n    " + 
+        clean_backtrace(original_exception).join("\n    ")
+      ]
+    end
+
     private
       def strip_base_path(file_name)
         file_name.gsub(@base_path, "")