I am not sure what I expected this book to be like. Stover is one of my very favorite authors, his Heroes Die series is really amazing. Test of Metal is a Magic the Gathering novel, which are notoriously terrible literature. So I guess it averages out. You can read Bret's summary of Test of Metal here.
Test of Metal is about a powerful creator of machines, Tezzeret, who falls under the power of a malicious dragon and is forced on a quest. It takes place in two time frames, one immediately after the other, with lots of switching in between. This was pretty confusing since it wasn't immediately obvious to me what was going on when characters were going back and forth between different situations.
Stover really excels at a certain type of story. A badass character is placed in a situation that shouldn't be survivable. All kinds of stuff is trying to catch him, kill him, eat him, whatever. (I use the male pronoun because the character is male in Test of Metal. It should be noted, however, that the main badass character was a woman in Iron Dawn and Jericho Moon) The badass character's only significant goal is survival. He is just such a badass that he fights his way out of the impossible situation. Barely. So Tezzeret is a slightly less interesting version of Stover's other characters. (mostly Cain from Heroes Die and Barra from Iron Dawn)
Surprisingly, I didn't feel like I was missing out by not having read previous Magic the Gathering novels. I tried to read one once, but it was too stupid to even tolerate. Test of Metal explained the setting, characters, magic, etc. sufficiently that it was not a problem to jump into the middle like I did here.
This book was what it was, and it did that ok. It was probably one of the better Magic the Gathering novels, because it had a Stover plot and Stoverized characters, but was still in a setting that makes no sense and has overpowered characters. I would really only recommend this book to someone who was crazy about Matthew Woodring Stover anyway, and then with hesitation. It wasn't a terrible book, but it was confusing in parts and not that groundbreaking or exciting.