| def factorial(n): |
| """Return the factorial of n, an exact integer >= 0. |
| |
| If the result is small enough to fit in an int, return an int. |
| Else return a long. |
| |
| >>> [factorial(n) for n in range(6)] |
| [1, 1, 2, 6, 24, 120] |
| """ |
| |
| import math |
| if not n >= 0: |
| raise ValueError("n must be >= 0") |
| if math.floor(n) != n: |
| raise ValueError("n must be exact integer") |
| if n+1 == n: # catch a value like 1e300 |
| raise OverflowError("n too large") |
| result = 1 |
| factor = 2 |
| while factor <= n: |
| result *= factor |
| factor += 1 |
| return result |
| |
| class FirstGoodTest: |
| """ |
| >>> [factorial(n) for n in range(6)] |
| [1, 1, 2, 6, 24, 120] |
| """ |
| def test_passes(self): |
| pass |
| |
| class SecondGoodTest: |
| def test_passes(self): |
| """ |
| >>> [factorial(n) for n in range(6)] |
| [1, 1, 2, 6, 24, 120] |
| """ |
| pass |
