1 files changed, 36 insertions, 0 deletions

diff --git a/spec/ruby/core/kernel/initialize_copy_spec.rb b/spec/ruby/core/kernel/initialize_copy_spec.rb
new file mode 100644
index 0000000000..ebac0c14de
--- /dev/null
+++ b/spec/ruby/core/kernel/initialize_copy_spec.rb
@@ -0,0 +1,36 @@
+require_relative '../../spec_helper'
+
+describe "Kernel#initialize_copy" do
+  it "returns self" do
+    obj = Object.new
+    obj.send(:initialize_copy, obj).should.equal?(obj)
+  end
+
+  it "does nothing if the argument is the same as the receiver" do
+    obj = Object.new
+    obj.send(:initialize_copy, obj).should.equal?(obj)
+
+    obj = Object.new.freeze
+    obj.send(:initialize_copy, obj).should.equal?(obj)
+
+    1.send(:initialize_copy, 1).should.equal?(1)
+  end
+
+  it "raises FrozenError if the receiver is frozen" do
+    -> { Object.new.freeze.send(:initialize_copy, Object.new) }.should.raise(FrozenError)
+    -> { 1.send(:initialize_copy, Object.new) }.should.raise(FrozenError)
+  end
+
+  it "raises TypeError if the objects are of different class" do
+    klass = Class.new
+    sub = Class.new(klass)
+    a = klass.new
+    b = sub.new
+    message = 'initialize_copy should take same class object'
+    -> { a.send(:initialize_copy, b) }.should.raise(TypeError, message)
+    -> { b.send(:initialize_copy, a) }.should.raise(TypeError, message)
+
+    -> { a.send(:initialize_copy, 1) }.should.raise(TypeError, message)
+    -> { a.send(:initialize_copy, 1.0) }.should.raise(TypeError, message)
+  end
+end