require 'abstract_unit'
require 'active_support/core_ext/hash/keys'
class TransformKeysTest < ActiveSupport::TestCase
test "transform_keys returns a new hash with the keys computed from the block" do
original = { a: 'a', b: 'b' }
mapped = original.transform_keys { |k| "#{k}!".to_sym }
assert_equal({ a: 'a', b: 'b' }, original)
assert_equal({ a!: 'a', b!: 'b' }, mapped)
end
test "transform_keys! modifies the keys of the original" do
original = { a: 'a', b: 'b' }
mapped = original.transform_keys! { |k| "#{k}!".to_sym }
assert_equal({ a!: 'a', b!: 'b' }, original)
assert_same original, mapped
end
test "transform_keys returns a sized Enumerator if no block is given" do
original = { a: 'a', b: 'b' }
enumerator = original.transform_keys
assert_equal original.size, enumerator.size
assert_equal Enumerator, enumerator.class
end
test "transform_keys! returns a sized Enumerator if no block is given" do
original = { a: 'a', b: 'b' }
enumerator = original.transform_keys!
assert_equal original.size, enumerator.size
assert_equal Enumerator, enumerator.class
end
test "transform_keys is chainable with Enumerable methods" do
original = { a: 'a', b: 'b' }
mapped = original.transform_keys.with_index { |k, i| [k, i].join.to_sym }
assert_equal({ a0: 'a', b1: 'b' }, mapped)
end
test "transform_keys! is chainable with Enumerable methods" do
original = { a: 'a', b: 'b' }
original.transform_keys!.with_index { |k, i| [k, i].join.to_sym }
assert_equal({ a0: 'a', b1: 'b' }, original)
end
test "transform_keys returns a Hash instance when self is inherited from Hash" do
class HashDescendant < ::Hash
def initialize(elements = nil)
super(elements)
(elements || {}).each_pair{ |key, value| self[key] = value }
end
end
original = HashDescendant.new({ a: 'a', b: 'b' })
mapped = original.transform_keys { |k| "#{k}!".to_sym }
assert_equal({ a: 'a', b: 'b' }, original)
assert_equal({ a!: 'a', b!: 'b' }, mapped)
assert_equal(::Hash, mapped.class)
end
end
