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require File.expand_path('../../../spec_helper', __FILE__)
require 'prime'
describe "Prime.prime_division" do
it "returns an array of a prime factor and a corresponding exponent" do
Prime.prime_division(2*3*5*7*11*13*17).should ==
[[2,1], [3,1], [5,1], [7,1], [11,1], [13,1], [17,1]]
end
it "returns an empty array for 1" do
Prime.prime_division(1).should == []
end
it "returns [[-1, 1]] for -1" do
Prime.prime_division(-1).should == [[-1, 1]]
end
it "includes [[-1, 1]] in the divisors of a negative number" do
Prime.prime_division(-10).should include([-1, 1])
end
it "raises ZeroDivisionError for 0" do
lambda { Prime.prime_division(0) }.should raise_error(ZeroDivisionError)
end
end
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