1 files changed, 23 insertions, 0 deletions
diff --git a/spec/ruby/core/set/intersection_spec.rb b/spec/ruby/core/set/intersection_spec.rb
new file mode 100644
index 0000000000..c14e1f62ad
--- /dev/null
+++ b/spec/ruby/core/set/intersection_spec.rb
@@ -0,0 +1,23 @@
+require_relative '../../spec_helper'
+
+describe "Set#intersection" do
+  it "is an alias of Set#&" do
+    Set.instance_method(:intersection).should == Set.instance_method(:&)
+  end
+end
+
+describe "Set#&" do
+  before :each do
+    @set = Set[:a, :b, :c]
+  end
+
+  it "returns a new Set containing only elements shared by self and the passed Enumerable" do
+    (@set & Set[:b, :c, :d, :e]).should == Set[:b, :c]
+    (@set & [:b, :c, :d]).should == Set[:b, :c]
+  end
+
+  it "raises an ArgumentError when passed a non-Enumerable" do
+    -> { @set & 1 }.should.raise(ArgumentError)
+    -> { @set & Object.new }.should.raise(ArgumentError)
+  end
+end