PASS Test content-type header for a body string 
FAIL Test content-type header for a body ArrayBufferView assert_equals: Correct Content-Type header result expected "" but got "application/x-www-form-urlencoded"
FAIL Test content-type header for a body ArrayBuffer assert_equals: Correct Content-Type header result expected "" but got "application/x-www-form-urlencoded"
PASS Test content-type header for a body Blob 
PASS Test content-type header for a body FormData 
PASS Test content-type header for a body URLSearchParams