```ruby
require 'rspec'
require 'fuzzbert'

describe FuzzBert::Mutator do

  describe "::new" do
    it "takes a (valid) base value" do
      value = "test"
      mut = FuzzBert::Mutator.new(value)
    end
  end

  describe "#generator" do
    it "implements Generation" do
      mut = FuzzBert::Mutator.new("value")
      mut.generator.should_not be_nil
    end
  end

  describe "#to_data" do
    it "mutates the base value in exactly one position" do
      value = "FuzzBert"
      mut = FuzzBert::Mutator.new(value)
      mutated = mut.to_data
      diff = 0
      value.each_byte.each_with_index do |b, i|
        diff += 1 unless b == mutated[i].ord
      end
      diff.should == 1
    end
  end

end

```

Change spec to check error not raised
user
```ruby
require 'rspec'
require 'fuzzbert'

describe FuzzBert::Mutator do

  describe "::new" do
    it "takes a (valid) base value" do
      value = "test"
      -> {FuzzBert::Mutator.new(value)}.should_not raise_error
    end
  end

  describe "#generator" do
    it "implements Generation" do
      mut = FuzzBert::Mutator.new("value")
      mut.generator.should_not be_nil
    end
  end

  describe "#to_data" do
    it "mutates the base value in exactly one position" do
      value = "FuzzBert"
      mut = FuzzBert::Mutator.new(value)
      mutated = mut.to_data
      diff = 0
      value.each_byte.each_with_index do |b, i|
        diff += 1 unless b == mutated[i].ord
      end
      diff.should == 1
    end
  end

end

```
assistant