how realistic is spark notes' practice test in relation to real sat subject tests???

Test Preparation
1

<p>well the question is the same as my title.
is spark notes diagnostic test realistic if it comes to us history and physics?
thanks</p>

2

<p>well, when i took sparknotes chem exams i got like 670, 720, 680. </p>

<p>on the real test i got a 790.</p>