Extra tests for thoughtbot#947 to check works in more situations

test/integration_test.rb

@@ -641,19 +641,36 @@ def s3_headers_for attachment, style
     end
   end
 
-  context "Copying attachment between models" do
+  context "Copying attachments between models" do
     setup do
       rebuild_model
       @file = File.new(fixture_file("5k.png"), 'rb')
     end
 
     teardown { @file.close }
 
-    should "should succeed when attachment is empty" do
+    should "succeed when original attachment is a file" do
+      original = Dummy.new
+      original.avatar = @file
+      assert original.save
+
+      copy = Dummy.new
+      copy.avatar = original.avatar
+      assert copy.save
+
+      assert copy.avatar.present?
+    end
+
+    should "succeed when original attachment is empty" do
       original = Dummy.create!
+
       copy = Dummy.new
+      copy.avatar = @file
+      assert copy.save
+      assert copy.avatar.present?
+
       copy.avatar = original.avatar
-      copy.save
+      assert copy.save
       assert !copy.avatar.present?
     end
   end