Get 'warning: Insecure world writable dir' as 'stderr' when using system "sdiff" in rake

Question

I got the error

stderr: ..../file.rb:66 : warning: Insecure world writable dir ... 

when I ran the integration test to test the code.

And in line 66 of that file.rb, I have

system "sdiff /tmp/download/file1.json /tmp/download/file2.json"

The sdiff shell command seemed to work. It printed out the content of those two files on the terminal side by side. FYI, line 66 is the last line of that function. Do I need to suppress the warning, or is there something wrong with the sdiff?

Any idea?

Thanks