dot.py

import pytest

def dot(a,b):
	res = 0
	for i in range(len(a)):
		res += a[i]*b[i]
	return res

#@ = decoration symbol. transforms the inmediately next function.
@pytest.mark.parametrize("a,b,expected",[
	([0,0],[0,0],0),
	([1,0],[0,1],0),
	([1,2],[2,-1],0),
])
def test_asser_equal(a,b,expected):
	assert dot(a,b) == expected

def test_dot_zeros():
	a = [0,0]
	b = [0,0]
	assert dot(a,b) == 0

def test_dot_perp():
	a = [0,1]
	b = [1,0]
	assert dot(a,b) == 0

def test_a_lessthan_b():
	a = [1,2]
	b = [1,2,3]

	with pytest.raises(AssertionError):	
		assert dot(a,b) == 3

def test_b_lessthan_a():
	a = [1,2]
	b = [1,2,3]

	with pytest.raises(AssertionError):
		assert dot(a,b) == 3