1 files changed, 71 insertions, 0 deletions
diff --git a/spec/ruby/core/objectspace/weakkeymap/element_set_spec.rb b/spec/ruby/core/objectspace/weakkeymap/element_set_spec.rb
new file mode 100644
index 0000000000..c427e01ca5
--- /dev/null
+++ b/spec/ruby/core/objectspace/weakkeymap/element_set_spec.rb
@@ -0,0 +1,71 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "3.3" do
+  describe "ObjectSpace::WeakKeyMap#[]=" do
+    def should_accept(map, key, value)
+      (map[key] = value).should == value
+      map.should.key?(key)
+      map[key].should == value
+    end
+
+    def should_not_accept(map, key, value)
+      -> { map[key] = value }.should raise_error(ArgumentError)
+    end
+
+    it "is correct" do
+      map = ObjectSpace::WeakKeyMap.new
+      key1, key2 = %w[a b].map(&:upcase)
+      ref1, ref2 = %w[x y]
+      should_accept(map, key1, ref1)
+      should_accept(map, key1, ref1)
+      should_accept(map, key2, ref2)
+      map[key1].should == ref1
+    end
+
+    it "requires the keys to implement #hash" do
+      map = ObjectSpace::WeakKeyMap.new
+      -> { map[BasicObject.new] = 1 }.should raise_error(NoMethodError, /undefined method [`']hash' for an instance of BasicObject/)
+    end
+
+    it "accepts frozen keys or values" do
+      map = ObjectSpace::WeakKeyMap.new
+      x = Object.new
+      should_accept(map, x, true)
+      should_accept(map, x, false)
+      should_accept(map, x, 42)
+      should_accept(map, x, :foo)
+
+      y = Object.new.freeze
+      should_accept(map, x, y)
+      should_accept(map, y, x)
+    end
+
+    it "rejects symbols as keys" do
+      map = ObjectSpace::WeakKeyMap.new
+      should_not_accept(map, :foo, true)
+      should_not_accept(map, rand.to_s.to_sym, true)
+    end
+
+    it "rejects integers as keys" do
+      map = ObjectSpace::WeakKeyMap.new
+      should_not_accept(map, 42, true)
+      should_not_accept(map, 2 ** 68, true)
+    end
+
+    it "rejects floats as keys" do
+      map = ObjectSpace::WeakKeyMap.new
+      should_not_accept(map, 4.2, true)
+    end
+
+    it "rejects booleans as keys" do
+      map = ObjectSpace::WeakKeyMap.new
+      should_not_accept(map, true, true)
+      should_not_accept(map, false, true)
+    end
+
+    it "rejects nil as keys" do
+      map = ObjectSpace::WeakKeyMap.new
+      should_not_accept(map, nil, true)
+    end
+  end
+end