1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
|
require File.expand_path('../../../../spec_helper', __FILE__)
require 'prime'
describe "Integer#prime_division" do
it "returns an array of a prime factor and a corresponding exponent" do
(2*3*5*7*11*13*17).prime_division.should ==
[[2,1], [3,1], [5,1], [7,1], [11,1], [13,1], [17,1]]
end
it "returns an empty array for 1" do
1.prime_division.should == []
end
it "returns an empty array for -1" do
-1.prime_division.should == [[-1, 1]]
end
it "raises ZeroDivisionError for 0" do
lambda { 0.prime_division }.should raise_error(ZeroDivisionError)
end
end
|
