B.F.
Welcome! I don't know of any groups in the Denton area, but would be surprised if you don't find one. If you end up a little closer in Frisco HIS is a very large, terrific homeschooling group. You may wish to try the Yahoo group HSM2HSM - Home school mom 2 home school mom. The women there are extremely knowlegdgable and you may make a friend or two before you even move here!
As to the testing; what do you want her tested for? If you simply want to see where she stands acedemically you can download the TAKS/TEKS test or have her take it online. Some people prefer the Iowa standardized tests. Please realize that Texas is the friendliest homeschool state, you do not have to have your daughter do any state testing at all! Her education is entirely in your hands, the state will not interfer. Relax and enjoy the freedom of homeschooling in Texas! Best of luck!