payerName attribute is null when option is undefined.
payerName attribute is null when requestPayerName is undefined.
payerName attribute is null when requestPayerName is false.
payerName attribute is 'web platform test' when requestPayerName is true.
payerName attribute is 'web platform test' when requestPayerName is truthy.

PASS Can construct a payment request (smoke test). 
PASS payerName attribute is null when option is undefined. 
PASS payerName attribute is null when requestPayerName is undefined. 
PASS payerName attribute is null when requestPayerName is false. 
PASS payerName attribute is 'web platform test' when requestPayerName is true. 
PASS payerName attribute is 'web platform test' when requestPayerName is truthy.