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require File.expand_path('../../../spec_helper', __FILE__)
require 'prime'
describe "Prime#prime?" do
it "returns a true value for prime numbers" do
Prime.prime?(2).should be_true
Prime.prime?(3).should be_true
Prime.prime?(2**31-1).should be_true # 8th Mersenne prime (M8)
end
it "returns a false value for composite numbers" do
Prime.prime?(4).should be_false
Prime.prime?(15).should be_false
Prime.prime?(2**32-1).should be_false
Prime.prime?( (2**17-1)*(2**19-1) ).should be_false # M6*M7
end
end
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