```ruby
require File.expand_path('../../../spec_helper', __FILE__)

describe "Time#dup" do
  it "returns a Time object that represents the same time" do
    t = Time.at(100)
    t.dup.tv_sec.should == t.tv_sec
  end

  it "copies the gmt state flag" do
    Time.now.gmtime.dup.gmt?.should == true
  end

  it "returns an independent Time object" do
    t = Time.now
    t2 = t.dup
    t.gmtime

    t2.gmt?.should == false
  end

  it "returns a subclass instance" do
    c = Class.new(Time)
    t = c.now

    t.should be_an_instance_of(c)
    t.dup.should be_an_instance_of(c)
  end
end
```

Add spec for creating instances of a cloned Time class
user
```ruby
require File.expand_path('../../../spec_helper', __FILE__)

describe "Time#dup" do
  it "returns a Time object that represents the same time" do
    t = Time.at(100)
    t.dup.tv_sec.should == t.tv_sec
  end

  it "copies the gmt state flag" do
    Time.now.gmtime.dup.gmt?.should == true
  end

  it "returns an independent Time object" do
    t = Time.now
    t2 = t.dup
    t.gmtime

    t2.gmt?.should == false
  end

  it "returns a subclass instance" do
    c = Class.new(Time)
    t = c.now

    t.should be_an_instance_of(c)
    t.dup.should be_an_instance_of(c)
  end

  it "returns a clone of Time instance" do
    c = Time.dup
    t = c.now

    t.should be_an_instance_of(c)
    t.should_not be_an_instance_of(Time)

    t.dup.should be_an_instance_of(c)
    t.dup.should_not be_an_instance_of(Time)
  end
end
```
assistant