#exercise 3.7 from "A primer on..."

"""
compute and return: sum_(k=1)^M (1/M)
"""

def sum_1k(M):
    s = 0
    for k in range(1,M+1):
        s += 1.0/k
    return s

def test_sum_1k():
    expected = 1.0+1.0/2+1.0/3
    computed = sum_1k(3)
    tol = 1e-10
    success = abs(expected-computed) < tol
    msg = f'Expected {expected}, got {computed}'
    assert success,msg


test_sum_1k()

print(sum_1k(2))
print(sum_1k(10))

"""
Terminal> python sum_func.py
1.5
2.9289682539682538
Note that there is no output from the call to the test
function, since the test passes.
"""