```ruby
#
# Author:: Tyler Ball (<tball@getchef.com>)
# Copyright:: Copyright (c) 2014 Opscode, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

class Chef
  module DSL
    module Audit

      # Can encompass tests in a `control` block or `describe` block
      # Adds the controls group and block (containing controls to execute) to the runner's list of pending examples
      def controls(*args, &block)
        raise ::Chef::Exceptions::NoAuditsProvided unless block
        name = args[0]
        raise AuditNameMissing if name.nil? || name.empty?

        run_context.controls[name] = { :args => args, :block => block }
      end

    end
  end
end
```

Raise error if duplicate controls block given.
user
```ruby
#
# Author:: Tyler Ball (<tball@getchef.com>)
# Copyright:: Copyright (c) 2014 Opscode, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

require 'chef/exceptions'

class Chef
  module DSL
    module Audit

      # Can encompass tests in a `control` block or `describe` block
      # Adds the controls group and block (containing controls to execute) to the runner's list of pending examples
      def controls(*args, &block)
        raise Chef::Exceptions::NoAuditsProvided unless block

        name = args[0]
        if name.nil? || name.empty?
          raise Chef::Exceptions::AuditNameMissing
        elsif run_context.controls.has_key?(name)
          raise Chef::Exceptions::AuditControlGroupDuplicate.new(name)
        end

        run_context.controls[name] = { :args => args, :block => block }
      end

    end
  end
end
```
assistant