Kindergarten teacher: too many tests

Washington Post reports that Susan Sluyter, who has taught as a kindergarten teacher for the past 20 years, resigned from her job due to the school system ramping up the academic pressure on her and her students.

In her resignation letter to Cambridge Public Schools, she cited that "her job required her to focus too much on teaching to standardized tests rather than to the needs of her students."

School officials have stated that they agree the tests may take time away from other learning, but they are a necessary step in studying learning patterns of the children.

How necessary are these tests? I was very surprised they have started giving them to kindergartners. I think this shows a very big flaw in our education system. We rely on a formulated equation that figures out what children need to learn, instead of the people that were trained to educate them. 

How do these tests benefit students learning? Can the teachers be better at diagnosing issues than the tests?