diff --git a/lib/paperclip/upfile.rb b/lib/paperclip/upfile.rb
index 3fb09bf..caeefdc 100644
--- a/lib/paperclip/upfile.rb
+++ b/lib/paperclip/upfile.rb
@@ -39,11 +39,6 @@ module Paperclip
     def original_filename
       @original_filename ||= File.basename(path)
     end
-
-    # Returns the size of the file.
-    def size
-      File.size(self)
-    end
   end
 end
 
diff --git a/test/upfile_test.rb b/test/upfile_test.rb
new file mode 100644
index 0000000..d6a37d2
--- /dev/null
+++ b/test/upfile_test.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class UpfileTest < Test::Unit::TestCase
+  context "content_type_from_ext" do
+    {
+      'lala' => 'application/x-octet-stream',
+      'lala.foo' => 'application/x-foo',
+      '__.jpg' => "image/jpeg",
+      '_.jpeg' => "image/jpeg",
+      '__.tif' => "image/tiff",
+      '_.tiff' => "image/tiff",
+
+      '_.png' => "image/png",
+      '_.gif' => "image/gif",
+      '_.bmp' => "image/bmp",
+      "_.webp" => "image/webp",
+
+      # '_.pngfoo' => 'application/x-pngfoo', # ??
+      # '_.htmfoo' => 'application/x-htmfoo', # ?
+
+      '_.csv' => "text/csv",
+      '_.xml' => "text/xml",
+      '_.css' => "text/css",
+      '_.js' => "text/js", # ???
+
+      '_.html' => 'text/html',
+      '__.htm' => 'text/html',
+
+
+      "_.txt" => "text/plain",
+      "_.liquid" => "text/x-liquid",
+      '_.svg' => 'image/svg+xml',
+      '_.xls' => 'application/vnd.ms-excel',
+    }.each_pair do |example, result|
+      should "return #{result} for #{example}" do
+        assert_equal result, Paperclip::Upfile.content_type_from_ext(example)
+      end
+    end
+  end
+end