potter_spec.py

from mamba import description, it

from itertools import groupby

def price(books):
    if not books:
        return 0

    numeroDeCada = [len(list(group)) for key, group in groupby(books)]

    numeroDeLibrosDistintos=len(numeroDeCada)
    cantidadDeLibros=min(numeroDeCada)
    
    precio = 8 * numeroDeLibrosDistintos * cantidadDeLibros
    
    if (numeroDeLibrosDistintos==2):
        return precio * 0.95
        
    return precio

with description('Potter kata') as self:
    with it('does not apply any discount with only one book'):
        assert 0 == price([])
        assert 8 == price([1])
        assert 8 == price([2])
        assert 8 == price([3])
        assert 8 == price([4])

    with it('does not apply a discount buying same book'):
        assert 16 == price([0, 0])
        assert 24 == price([1, 1, 1])

    with context('when applying discounts'):
        with it('applies a 95% discount when two different books'):
            assert 8 * 2 * 0.95 == price([0, 1])
            assert 8 * 3 * 0.9 == price([0, 2, 4]))

#def testBasics
#  assert_equal(0, price([]))
#  assert_equal(8, price([0]))
#  assert_equal(8, price([1]))
#  assert_equal(8, price([2]))
#  assert_equal(8, price([3]))
#  assert_equal(8, price([4]))
#  assert_equal(8 * 2, price([0, 0]))
#  assert_equal(8 * 3, price([1, 1, 1]))
#end

#def testSimpleDiscounts
#  assert_equal(8 * 2 * 0.95, price([0, 1]))
#  assert_equal(8 * 3 * 0.9, price([0, 2, 4]))
#  assert_equal(8 * 4 * 0.8, price([0, 1, 2, 4]))
#  assert_equal(8 * 5 * 0.75, price([0, 1, 2, 3, 4]))
#end

#def testSeveralDiscounts
#  assert_equal(8 + (8 * 2 * 0.95), price([0, 0, 1]))
#  assert_equal(2 * (8 * 2 * 0.95), price([0, 0, 1, 1]))
#  assert_equal((8 * 4 * 0.8) + (8 * 2 * 0.95), price([0, 0, 1, 2, 2, 3]))
#  assert_equal(8 + (8 * 5 * 0.75), price([0, 1, 1, 2, 3, 4]))
#end

#def testEdgeCases
#  assert_equal(2 * (8 * 4 * 0.8), price([0, 0, 1, 1, 2, 2, 3, 4]))
#  assert_equal(3 * (8 * 5 * 0.75) + 2 * (8 * 4 * 0.8),
#    price([0, 0, 0, 0, 0,
#           1, 1, 1, 1, 1,
#           2, 2, 2, 2,
#           3, 3, 3, 3, 3,
#           4, 4, 4, 4]))
#end