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require "spec_helper"
def factorial(n)
if n == 0
1
else
n * factorial(n-1)
end
end
def fibonacci(n)
n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2)
end
def fibonacci_enumerator
Enumerator.new do |yielder|
i, j = 0, 1
loop do
i, j = j, i + j
yielder.yield i
end
end
end
describe "fibonacci" do
let(:sut) { Fibonacci.new }
xit "should return the correct result" do
#0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144
expect(sut.get(0)).to eq(0)
expect(sut.get(1)).to eq(1)
end
it "should return the first n numbers in fibonacci" do
f = ->(x){ x < 2 ? x : f.call(x-1) + f.call(x-2) }
20.times do |n|
expect(fibonacci(n)).to eq(f.call(n))
end
end
it "can enumerate forever" do
fibonacci_enumerator.take_while { |n| n < 1000 }
end
it "can do factorial" do
(1..10).each do |n|
expect(factorial(n)).to eq((1..n).inject { |total, i| (i) * total })
end
end
end
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