require_relative '../../spec_helper'

describe 'Range#minmax' do
  before(:each) do
    @x = mock('x')
    @y = mock('y')

    @x.should_receive(:<=>).with(@y).any_number_of_times.and_return(-1) # x < y
    @x.should_receive(:<=>).with(@x).any_number_of_times.and_return(0) # x == x
    @y.should_receive(:<=>).with(@x).any_number_of_times.and_return(1) # y > x
    @y.should_receive(:<=>).with(@y).any_number_of_times.and_return(0) # y == y
  end

  describe 'on an inclusive range' do
    it 'should raise RangeError on an endless range without iterating the range' do
      @x.should_not_receive(:succ)

      range = (@x..)

      -> { range.minmax }.should raise_error(RangeError, 'cannot get the maximum of endless range')
    end

    it 'raises RangeError or ArgumentError on a beginless range' do
      range = (..@x)

      -> { range.minmax }.should raise_error(StandardError) { |e|
        if RangeError === e
          # error from #min
          -> { raise e }.should raise_error(RangeError, 'cannot get the minimum of beginless range')
        else
          # error from #max
          -> { raise e }.should raise_error(ArgumentError, 'comparison of NilClass with MockObject failed')
        end
      }
    end

    it 'should return beginning of range if beginning and end are equal without iterating the range' do
      @x.should_not_receive(:succ)

      (@x..@x).minmax.should == [@x, @x]
    end

    it 'should return nil pair if beginning is greater than end without iterating the range' do
      @y.should_not_receive(:succ)

      (@y..@x).minmax.should == [nil, nil]
    end

    it 'should return the minimum and maximum values for a non-numeric range without iterating the range' do
      @x.should_not_receive(:succ)

      (@x..@y).minmax.should == [@x, @y]
    end

    it 'should return the minimum and maximum values for a numeric range' do
      (1..3).minmax.should == [1, 3]
    end

    it 'should return the minimum and maximum values for a numeric range without iterating the range' do
      # We cannot set expectations on integers,
      # so we "prevent" iteration by picking a value that would iterate until the spec times out.
      range_end = Float::INFINITY

      (1..range_end).minmax.should == [1, range_end]
    end

    it 'should return the minimum and maximum values according to the provided block by iterating the range' do
      @x.should_receive(:succ).once.and_return(@y)

      (@x..@y).minmax { |x, y| - (x <=> y) }.should == [@y, @x]
    end
  end

  describe 'on an exclusive range' do
    it 'should raise RangeError on an endless range' do
      @x.should_not_receive(:succ)
      range = (@x...)

      -> { range.minmax }.should raise_error(RangeError, 'cannot get the maximum of endless range')
    end

    it 'should raise RangeError on a beginless range' do
      range = (...@x)

      -> { range.minmax }.should raise_error(RangeError,
        /cannot get the maximum of beginless range with custom comparison method|cannot get the minimum of beginless range/)
    end

    it 'should return nil pair if beginning and end are equal without iterating the range' do
      @x.should_not_receive(:succ)

      (@x...@x).minmax.should == [nil, nil]
    end

    it 'should return nil pair if beginning is greater than end without iterating the range' do
      @y.should_not_receive(:succ)

      (@y...@x).minmax.should == [nil, nil]
    end

    it 'should return the minimum and maximum values for a non-numeric range by iterating the range' do
      @x.should_receive(:succ).once.and_return(@y)

      (@x...@y).minmax.should == [@x, @x]
    end

    it 'should return the minimum and maximum values for a numeric range' do
      (1...3).minmax.should == [1, 2]
    end

    it 'should return the minimum and maximum values for a numeric range without iterating the range' do
      # We cannot set expectations on integers,
      # so we "prevent" iteration by picking a value that would iterate until the spec times out.
      range_end = bignum_value

      (1...range_end).minmax.should == [1, range_end - 1]
    end

    it 'raises TypeError if the end value is not an integer' do
      range = (0...Float::INFINITY)
      -> { range.minmax }.should raise_error(TypeError, 'cannot exclude non Integer end value')
    end

    it 'should return the minimum and maximum values according to the provided block by iterating the range' do
      @x.should_receive(:succ).once.and_return(@y)

      (@x...@y).minmax { |x, y| - (x <=> y) }.should == [@x, @x]
    end
  end
end
