Renamed files ignored

I renamed a file, but didn't change the contents of the file. I would expect the parsed diff to provide information on the details of the rename, but instead it returns nothing. Is this expected behaviour?

```ruby
my_diff = <<-DIFF
diff --git a/goonfile b/Gemfile
similarity index 100%
rename from goonfile
rename to Gemfile
DIFF

parsed = GitDiffParser.parse(my_diff)
# => []
```