My daughter just completed the end-of-year math test for 4th grade. She scored 82%. She missed doing one question (just forgot), made a few careless mistakes, and then missed several in the measuring unit section because she didn't remember how many ounces are in a pound or how many grams in a kilogram. So we need to review some of that.
But overall, I am happy with the results, because (and I knew this beforehand too) she understands the concepts well! That is the most important thing. It's always easy to review some forgotten facts (such as measuring units), but when child has not understood the main concepts, the "patch-up" work is more tedious.
I have provided these Math Mammoth end-of-year tests on my site as free downloads so that people can use them as placement tests or for general math assessment. I often have people email me about their kids' results, and based on that, I feel those tests are working fine.
I have also collected a few other math assessment resources on this page, notably the yearly tests from Texas, Florida, and California (which are free) and a few commercial resources. Note: in my opinion, California's math standards are a bit too advanced, so use care when using their tests.
Some parents are against testing, but I feel testing for assessment is often needful in order to know what the child knows and doesn't know. The tests are like a "diagnostic toolbox" for me when I need to guide parents in what Math Mammoth books they might need for their children. So the purpose is not to "put on the pressure", but just to find out.