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require 'spec_helper'
describe Immutable::SortedSet do
describe '#drop' do
[
[[], 0, []],
[[], 10, []],
[['A'], 10, []],
[%w[A B C], 0, %w[A B C]],
[%w[A B C], 1, %w[B C]],
[%w[A B C], 2, ['C']],
[%w[A B C], 3, []]
].each do |values, number, expected|
context "#{number} from #{values.inspect}" do
let(:sorted_set) { SS[*values] }
it 'preserves the original' do
sorted_set.drop(number)
sorted_set.should eql(SS[*values])
end
it "returns #{expected.inspect}" do
sorted_set.drop(number).should eql(SS[*expected])
end
end
end
context 'when argument is zero' do
let(:sorted_set) { SS[6, 7, 8, 9] }
it 'returns self' do
sorted_set.drop(0).should be(sorted_set)
end
end
context 'when the set has a custom order' do
let(:sorted_set) { SS.new([1, 2, 3], &:-@)}
it 'maintains the custom order' do
sorted_set.drop(1).to_a.should == [2, 1]
sorted_set.drop(2).to_a.should == [1]
end
it 'keeps the comparator even when set is cleared' do
s = sorted_set.drop(3)
s.add(4).add(5).add(6).to_a.should == [6, 5, 4]
end
end
context 'when called on a subclass' do
it 'should return an instance of the subclass' do
subclass = Class.new(Immutable::SortedSet)
subclass.new([1,2,3]).drop(1).class.should be(subclass)
end
end
end
end
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