mirror of
https://github.com/edgecase/ruby_koans.git
synced 2026-04-14 23:13:20 -04:00
127 lines
3.2 KiB
Ruby
127 lines
3.2 KiB
Ruby
require File.expand_path(File.dirname(__FILE__) + '/neo')
|
|
|
|
class AboutHashes < Neo::Koan
|
|
def test_creating_hashes
|
|
empty_hash = Hash.new
|
|
assert_equal __(Hash), empty_hash.class
|
|
assert_equal(__({}), empty_hash)
|
|
assert_equal __(0), empty_hash.size
|
|
end
|
|
|
|
def test_hash_literals
|
|
hash = { :one => "uno", :two => "dos" }
|
|
assert_equal __(2), hash.size
|
|
end
|
|
|
|
def test_accessing_hashes
|
|
hash = { :one => "uno", :two => "dos" }
|
|
assert_equal __("uno"), hash[:one]
|
|
assert_equal __("dos"), hash[:two]
|
|
assert_equal __(nil), hash[:doesnt_exist]
|
|
end
|
|
|
|
def test_accessing_hashes_with_fetch
|
|
hash = { :one => "uno" }
|
|
assert_equal __("uno"), hash.fetch(:one)
|
|
assert_raise(___(IndexError, KeyError)) do
|
|
hash.fetch(:doesnt_exist)
|
|
end
|
|
|
|
# THINK ABOUT IT:
|
|
#
|
|
# Why might you want to use #fetch instead of #[] when accessing hash keys?
|
|
end
|
|
|
|
def test_changing_hashes
|
|
hash = { :one => "uno", :two => "dos" }
|
|
hash[:one] = "eins"
|
|
|
|
expected = { :one => __("eins"), :two => "dos" }
|
|
assert_equal __(expected), hash
|
|
|
|
# Bonus Question: Why was "expected" broken out into a variable
|
|
# rather than used as a literal?
|
|
end
|
|
|
|
def test_hash_is_unordered
|
|
hash1 = { :one => "uno", :two => "dos" }
|
|
hash2 = { :two => "dos", :one => "uno" }
|
|
|
|
assert_equal __(true), hash1 == hash2
|
|
end
|
|
|
|
def test_hash_keys
|
|
hash = { :one => "uno", :two => "dos" }
|
|
assert_equal __(2), hash.keys.size
|
|
assert_equal __(true), hash.keys.include?(:one)
|
|
assert_equal __(true), hash.keys.include?(:two)
|
|
assert_equal __(Array), hash.keys.class
|
|
end
|
|
|
|
def test_hash_values
|
|
hash = { :one => "uno", :two => "dos" }
|
|
assert_equal __(2), hash.values.size
|
|
assert_equal __(true), hash.values.include?("uno")
|
|
assert_equal __(true), hash.values.include?("dos")
|
|
assert_equal __(Array), hash.values.class
|
|
end
|
|
|
|
def test_combining_hashes
|
|
hash = { "jim" => 53, "amy" => 20, "dan" => 23 }
|
|
new_hash = hash.merge({ "jim" => 54, "jenny" => 26 })
|
|
|
|
assert_equal __(true), hash != new_hash
|
|
|
|
expected = { "jim" => __(54), "amy" => 20, "dan" => 23, "jenny" => __(26) }
|
|
assert_equal __(true), expected == new_hash
|
|
end
|
|
|
|
def test_default_value
|
|
hash1 = Hash.new
|
|
hash1[:one] = 1
|
|
|
|
assert_equal __(1), hash1[:one]
|
|
assert_equal __(nil), hash1[:two]
|
|
|
|
hash2 = Hash.new("dos")
|
|
hash2[:one] = 1
|
|
|
|
assert_equal __(1), hash2[:one]
|
|
assert_equal __("dos"), hash2[:two]
|
|
end
|
|
|
|
def test_default_value_is_the_same_object
|
|
hash = Hash.new([])
|
|
|
|
hash[:one] << "uno"
|
|
hash[:two] << "dos"
|
|
|
|
assert_equal __(["uno", "dos"]), hash[:one]
|
|
assert_equal __(["uno", "dos"]), hash[:two]
|
|
assert_equal __(["uno", "dos"]), hash[:three]
|
|
|
|
assert_equal __(true), hash[:one].object_id == hash[:two].object_id
|
|
end
|
|
|
|
def test_default_value_with_block
|
|
hash = Hash.new {|hash, key| hash[key] = [] }
|
|
|
|
hash[:one] << "uno"
|
|
hash[:two] << "dos"
|
|
|
|
assert_equal __(["uno"]), hash[:one]
|
|
assert_equal __(["dos"]), hash[:two]
|
|
assert_equal __([]), hash[:three]
|
|
end
|
|
|
|
def test_default_value_attribute
|
|
hash = Hash.new
|
|
|
|
assert_equal __(nil), hash[:some_key]
|
|
|
|
hash.default = 'peanut'
|
|
|
|
assert_equal __('peanut'), hash[:some_key]
|
|
end
|
|
end
|