ruby-koans/about_arrays.rb
2023-12-27 00:25:48 +05:30

85 lines
2.1 KiB
Ruby

require File.expand_path(File.dirname(__FILE__) + '/neo')
class AboutArrays < Neo::Koan
def test_creating_arrays
empty_array = Array.new
assert_equal Array, empty_array.class
assert_equal 0, empty_array.size
end
def test_array_literals
array = Array.new
assert_equal [], array
array[0] = 1
assert_equal [1], array
array[1] = 2
assert_equal [1, 2], array
array << 333
assert_equal [1, 2, 333], array
end
def test_accessing_array_elements
array = [:peanut, :butter, :and, :jelly]
assert_equal :peanut, array[0]
assert_equal :peanut, array.first
assert_equal :jelly, array[3]
assert_equal :jelly, array.last
assert_equal :jelly, array[-1]
assert_equal :butter, array[-3]
end
def test_slicing_arrays
array = [:peanut, :butter, :and, :jelly]
assert_equal [:peanut], array[0,1]
assert_equal [:peanut, :butter], array[0,2]
assert_equal [:and, :jelly], array[2,2]
assert_equal [:and, :jelly], array[2,20]
assert_equal [], array[4,0] # NOTE: weird, you expect it to be nil but it's not. So upto `length` index, you get array back
assert_equal [], array[4,100] # same weirdness as above
assert_equal nil, array[5,0]
end
def test_arrays_and_ranges
assert_equal Range, (1..5).class
assert_not_equal [1,2,3,4,5], (1..5)
assert_equal [1, 2, 3, 4, 5], (1..5).to_a # also weird, i thought .. should be exclusive
assert_equal [1, 2, 3, 4], (1...5).to_a
end
def test_slicing_with_ranges
array = [:peanut, :butter, :and, :jelly]
assert_equal [:peanut, :butter, :and], array[0..2]
assert_equal [:peanut, :butter], array[0...2]
assert_equal [:and, :jelly], array[2..-1]
end
def test_pushing_and_popping_arrays
array = [1,2]
array.push(:last)
assert_equal [1, 2, :last], array
popped_value = array.pop
assert_equal :last, popped_value
assert_equal [1, 2], array
end
def test_shifting_arrays
array = [1,2]
array.unshift(:first)
assert_equal [:first, 1, 2], array
shifted_value = array.shift
assert_equal :first, shifted_value
assert_equal [1, 2], array
end
end