The poem "Barbie Doll" by Marge Piercy tells the story of a young girls who is told she has a "big nose" and "fat legs." Despite all evidence to the contrary, this young girl believed the lie and committed suicide. This is a tragic story of unrealistic expectations, as demonstrated first by the title. Barbie is the epitome of unrealistic expectations.
The phrase you ask about is found in the second stanza of the poem. Here the speaker outlines all the fine qualities of this young girl.
She was healthy, tested intelligent,
possessed strong arms and back,
abundant sexual drive and manual dexterity.
This girl is in good health, is bright, is physically fit, and has normal desires and coordination. The "tested intelligent" obviously refers to her intellectual capacity; she is capable of learning.
The tragedy of this poem is that a perfectly "normal" girl was persuaded to believe she was not by a few careless words spoken by a young classmate.