。
She's worried about how her son's test results will turn out.
Literal
She [topic-は] son [genitive-の] test results [subject-が] how-will-become [quotative-と] is-worrying.
An embedded question fed to 心配する via the quotative と. The inner clause 息子のテスト結果がどうなるか ('how will son's test results turn out') is a 'how-will-X-become' question, with か marking the question force; the outer と makes it the content of worry. This frame is productive: ~とは心配する patterns let you pack a wonder/worry-about-X clause as the topic of concern. テスト is a katakana loanword from English.