Add Set#intersect? and #disjoint?.

* lib/set.rb (Set#intersect?, Set#disjoint?): Add new methods for
  testing if two sets have any element in common.
  [ruby-core:45641] [Feature #6588] Based on the code by marcandre.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42253 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 40 insertions, 0 deletions

diff --git a/test/test_set.rb b/test/test_set.rb
index cbf4eb0234..1f6f2436f5 100644
--- a/test/test_set.rb
+++ b/test/test_set.rb
@@ -297,6 +297,46 @@ class TC_Set < Test::Unit::TestCase
     assert_equal(false, Set[].proper_subset?(Set[]))
   end
 
+  def assert_intersect(expected, set, other)
+    case expected
+    when true
+      assert_send([set, :intersect?, other])
+      assert_send([other, :intersect?, set])
+      assert_not_send([set, :disjoint?, other])
+      assert_not_send([other, :disjoint?, set])
+    when false
+      assert_not_send([set, :intersect?, other])
+      assert_not_send([other, :intersect?, set])
+      assert_send([set, :disjoint?, other])
+      assert_send([other, :disjoint?, set])
+    when Class
+      assert_raises(expected) {
+        set.intersect?(other)
+      }
+      assert_raises(expected) {
+        set.disjoint?(other)
+      }
+    else
+      raise ArgumentError, "%s: unsupported expected value: %s" % [__method__, expected.inspect]
+    end
+  end
+
+  def test_intersect?
+    set = Set[3,4,5]
+
+    assert_intersect(ArgumentError, set, 3)
+    assert_intersect(ArgumentError, set, [2,4,6])
+
+    assert_intersect(true, set, Set[2,4])
+    assert_intersect(true, set, Set[5,6,7])
+    assert_intersect(true, set, Set[1,2,6,8,4])
+
+    assert_intersect(false, set, Set[])
+    assert_intersect(false, set, Set[0,2])
+    assert_intersect(false, set, Set[0,2,6])
+    assert_intersect(false, set, Set[0,2,6,8,10])
+  end
+
   def test_each
     ary = [1,3,5,7,10,20]
     set = Set.new(ary)