sumPrimes(10)应该返回一个数字。
    testString: 'assert.deepEqual(typeof sumPrimes(10), "number", "sumPrimes(10) should return a number.");'
  - text: sumPrimes(10)应该返回17。
    testString: 'assert.deepEqual(sumPrimes(10), 17, "sumPrimes(10) should return 17.");'
  - text: sumPrimes(977)应该返回73156。
    testString: 'assert.deepEqual(sumPrimes(977), 73156, "sumPrimes(977) should return 73156.");'
```