1 files changed, 56 insertions, 0 deletions
diff --git a/spec/ruby/core/module/extend_object_spec.rb b/spec/ruby/core/module/extend_object_spec.rb
new file mode 100644
index 0000000000..1fd1abc0b5
--- /dev/null
+++ b/spec/ruby/core/module/extend_object_spec.rb
@@ -0,0 +1,56 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "Module#extend_object" do
+  before :each do
+    ScratchPad.clear
+  end
+
+  it "is a private method" do
+    Module.should have_private_instance_method(:extend_object)
+  end
+
+  describe "on Class" do
+    it "is undefined" do
+      Class.should_not have_private_instance_method(:extend_object, true)
+    end
+
+    it "raises a TypeError if calling after rebinded to Class" do
+      -> {
+        Module.instance_method(:extend_object).bind(Class.new).call Object.new
+      }.should raise_error(TypeError)
+    end
+  end
+
+  it "is called when #extend is called on an object" do
+    ModuleSpecs::ExtendObject.should_receive(:extend_object)
+    obj = mock("extended object")
+    obj.extend ModuleSpecs::ExtendObject
+  end
+
+  it "extends the given object with its constants and methods by default" do
+    obj = mock("extended direct")
+    ModuleSpecs::ExtendObject.send :extend_object, obj
+
+    obj.test_method.should == "hello test"
+    obj.singleton_class.const_get(:C).should == :test
+  end
+
+  it "is called even when private" do
+    obj = mock("extended private")
+    obj.extend ModuleSpecs::ExtendObjectPrivate
+    ScratchPad.recorded.should == :extended
+  end
+
+  describe "when given a frozen object" do
+    before :each do
+      @receiver = Module.new
+      @object = Object.new.freeze
+    end
+
+    it "raises a RuntimeError before extending the object" do
+      -> { @receiver.send(:extend_object, @object) }.should raise_error(RuntimeError)
+      @object.should_not be_kind_of(@receiver)
+    end
+  end
+end