Import set 1.0.0

- SortedSet has been removed for dependency and performance reasons.
- Set#join is added as a shorthand for `.to_a.join`.
- Set#<=> is added.

https://github.com/ruby/set/blob/v1.0.0/CHANGELOG.md

1 files changed, 5 insertions, 0 deletions

diff --git a/test/test_set.rb b/test/test_set.rb
index 05431e4c63..e62f30d852 100644
--- a/test/test_set.rb
+++ b/test/test_set.rb
@@ -759,6 +759,11 @@ class TC_Set < Test::Unit::TestCase
     assert_equal Set[1,2,3], set1
   end if Kernel.instance_method(:initialize_clone).arity != 1
 
+  def test_join
+    assert_equal('123', Set[1, 2, 3].join)
+    assert_equal('1 & 2 & 3', Set[1, 2, 3].join(' & '))
+  end
+
   def test_inspect
     set1 = Set[1, 2]
     assert_equal('#<Set: {1, 2}>', set1.inspect)