Pearl's upset about us having an examination (7)
I believe the answer is:
perusal
'an examination' is the definition.
(I've seen this before)
'pearl's upset about us' is the wordplay.
'upset' indicates an anagram.
'about' means one lot of letters goes inside another.
'pearl' with letters rearranged gives 'peral'.
'peral' going around 'us' is 'PERUSAL'.
'having' is the link.
(Other definitions for perusal that I've seen before include "thorough scan" , "Thorough read-through" , "Careful reading" , "worth a close look" , "Examination, survey" .)