"""
Exercise 3.7 from "A primer on...
write a function that computes
a sum, and a test function for verifying 
that the function works as intended.
"""

def sum_1k(M):
    s = 0
    for k in range(1, M+1):
        s += 1 / k
    return s

def test_sum_1k():
    tol = 1e-10
    expected = 11 / 6
    computed = sum_1k(3)
    success = abs(expected - computed) < tol
    assert success


"""
Run with pytest:
Terminal> pytest sum_func.py 
============================= test session starts ==============================
platform darwin -- Python 3.9.7, pytest-6.2.4, py-1.10.0, pluggy-0.13.1
rootdir: /Users/sundnes/Desktop/IN1900_10_sept
plugins: anyio-2.2.0, mock-3.10.0, cov-3.0.0
collected 1 item                                                               

sum_func.py .                                                            [100%]

============================== 1 passed in 0.02s ===============================
"""