it "raises a TypeError when the given String can't be fully converted to a Float" do
    lambda { Float('0.0.0')  }.should raise_error(ArgumentError)
end

# Possibility 1
it "raises a TypeError when the given String can't be fully converted to a Float", :should_raise => ArgumentError do
  Float('0.0.0')
end

# Possibility 2
it_should_raise(ArgumentError) do
  Float('0.0.0')
end