The WASL is a test of what 4th graders should know near the end of 4th grade. The WASL is a test of what 4th grades aren't expected to learn or know until grades 7 and 10 according the the EALR standards defined by the state. In fact, manual scoring is very unreliable, has not been validated.
Many problems have more than one, or no correct solution, or require guessing.
That's not counting development costs, and takes days, not hours from teaching. In fact, it does not compare students to other nations or states. It not based on any other national or state standard. It is not even compliant with our own EALR standard. It was actually created by a consensus process which is applied to every other state with a similar test.