I took the “special agent test,” so the one I took might be different; however, i'm sure they're pretty similar. In my case, I ended up getting through the first test, then failing the second.
I found the test to be fairly difficult. The first test is a situational/behavioral test. What would you do if you had two deadlines due at the same time? It's hard to know which answer they were looking for and it was very grey. Multiple answers would have worked; it really depended on what the IRS was looking for within that department. For a different organization, the other answers would have worked better. Networking might help as you could determine what traits the organization generally valued/looked for in candidates.
The second test consisted of the first test (ie. what would you do under xyz situations), but it also had contained Financial statement questions. Without an audit background, this section of the test was brutal (ie. which item would likely indicate that a fraud was occurring-a change in xyz related to a change in ABC?). In addition, this section of the test had general math questions, which you might find within a basic college math class; this wouldn't have been too difficult, but YOU HAVE TO CALCULATE EVERYTHING BY HAND, throughout the entire test (not just this section). The numbers they gave were typically fairly difficult to work with and would eat up a lot of time.
B=84 This exam was such a b**** that I thought I failed-don't know how these things work
A=76 Slacker I am, I'll happily take it
R=81 I LOVE taxes
F=80 I don't wanna get banned for an expletive I'm thinking with "yea" proceeding it