Speaking of PARCC, here's the state breakdown

EdWeek has an updated breakdown of which states are going with which test. Note that about half the kids in the U.S. are taking neither PARCC nor Smarter Balanced; at this point, that does include Massachusetts, which is in the "undecided" column.
About eight million kids are in PARCC states; about 12 million are in Smarter Balanced states.