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require 'spec_helper'
describe Immutable::List do
describe '#rotate' do
let(:list) { L[1,2,3,4,5] }
context 'when passed no argument' do
it 'returns a new list with the first element moved to the end' do
list.rotate.should eql(L[2,3,4,5,1])
end
end
context 'with an integral argument n' do
it 'returns a new list with the first (n % size) elements moved to the end' do
list.rotate(2).should eql(L[3,4,5,1,2])
list.rotate(3).should eql(L[4,5,1,2,3])
list.rotate(4).should eql(L[5,1,2,3,4])
list.rotate(5).should eql(L[1,2,3,4,5])
list.rotate(-1).should eql(L[5,1,2,3,4])
end
end
context 'with a non-numeric argument' do
it 'raises a TypeError' do
-> { list.rotate('hello') }.should raise_error(TypeError)
end
end
context 'with an argument of zero (or one evenly divisible by list length)' do
it 'it returns self' do
list.rotate(0).should be(list)
list.rotate(5).should be(list)
end
end
end
end
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