Rails: Hash#assert_valid_keys

Documentation
None

Usage
Hash#assert_valid_keys gives you the ability to verify that each of the keys in the Hash are expected. For example, if you take an options Hash as an argument to a method you may want to validate that only expected options are passed as part of the hash; assert_valid_keys gives you the ability to list the keys you expect.

Test

require 'rubygems'
require 'active_support'
require 'test/unit'
require 'dust'

unit_tests do
  test "raise argument error on unexpected key" do
    assert_raises ArgumentError do
      {:invalid_key => :a, :valid_key => :b}.assert_valid_keys(:valid_key)
    end
  end
end