numberLetterCounts(5) should return a number.
testString: assert(typeof numberLetterCounts(5) === 'number');
- text: numberLetterCounts(5) should return 19.
testString: assert.strictEqual(numberLetterCounts(5), 19);
- text: numberLetterCounts(150) should return 1903.
testString: assert.strictEqual(numberLetterCounts(150), 1903);
- text: numberLetterCounts(1000) should return 21124.
testString: assert.strictEqual(numberLetterCounts(1000), 21124);
```