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

ruby_version_is "1.9" do
  describe "File.absolute_path" do
    before(:each) do
      @abs = File.expand_path(__FILE__)
    end

    it "returns the argument if it's an absolute pathname" do
      File.absolute_path(@abs).should == @abs
    end

    it "resolves paths relative to the current working directory" do
      path = File.dirname(@abs)
      Dir.chdir(path) do
        File.absolute_path('hello.txt').should == File.join(path, 'hello.txt')
      end
    end

    it "doesn't expand '~'" do
      File.absolute_path('~').should_not == File.expand_path('~')
    end

    it "accepts a second argument of a directory from which to resolve the path" do
      File.absolute_path(__FILE__, File.dirname(__FILE__)).should == @abs
    end

    it "calls #to_path on its argument" do
      File.absolute_path(mock_to_path(@abs)).should == @abs
    end
  end
end
```

Add spec for receiving '~user' in File.absolute_path.
user
```ruby
require File.expand_path('../../../spec_helper', __FILE__)

ruby_version_is "1.9" do
  describe "File.absolute_path" do
    before(:each) do
      @abs = File.expand_path(__FILE__)
    end

    it "returns the argument if it's an absolute pathname" do
      File.absolute_path(@abs).should == @abs
    end

    it "resolves paths relative to the current working directory" do
      path = File.dirname(@abs)
      Dir.chdir(path) do
        File.absolute_path('hello.txt').should == File.join(path, 'hello.txt')
      end
    end

    it "does not expand '~' to a home directory." do
      File.absolute_path('~').should_not == File.expand_path('~')
    end

    it "does not expand '~user' to a home directory." do
      path = File.dirname(@abs)
      Dir.chdir(path) do
        File.absolute_path('~user').should == File.join(path, '~user') 
      end
    end

    it "accepts a second argument of a directory from which to resolve the path" do
      File.absolute_path(__FILE__, File.dirname(__FILE__)).should == @abs
    end

    it "calls #to_path on its argument" do
      File.absolute_path(mock_to_path(@abs)).should == @abs
    end
  end
end
```
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