Memoized Tests

Memoized will memoize the results of your methods. It acts much like ActiveSupport::Memoizable without all of that freezing business. The API for unmemoizing is also a bit more explicit.

Install

$ gem install memoized

Usage

To define a memoized instance method, use memoize def:

class A
  include Memoized

  memoize def hello
    'hello!'
  end
end

You may also memoize one or more methods after they have been defined:

class B
  include Memoized

  def hello
    'hello!'
  end

  def goodbye
    'goodbye :('
  end

  memoize :hello, :goodbye
end

Memoizing class methods works the same way:

class C
  class << self
    include Memoized

    memoize def hello
      'hello!'
    end
  end
end

To unmemoize a specific method:

instance = A.new
instance.hello              # the hello method is now memoized
instance.unmemoize(:hello)  # the hello method is no longer memoized
instance.hello              # the hello method is run again and re-memoized

To unmemoize all methods for an instance:

instance = B.new
instance.hello          # the hello method is now memoized
instance.goodbye        # the goodbye method is now memoized
instance.unmemoize_all  # neither hello nor goodbye are memoized anymore

Limitations

When you are using Memoized with default arguments or default keyword arguments, there are some edge cased you have to keep in mind.

When you memoize a method with (keyword) arguments that have an expression as default value, you should be aware that the expression is evaluated only once.

memoize def print_time(time = Time.now)
  time
end

print_time
=> 2021-07-23 14:23:18 +0200

sleep(1.minute)
print_time
=> 2021-07-23 14:23:18 +0200

When you memoize a method with (keyword) arguments that have default values, you should be aware that Memoized differentiates between a method call without arguments and the default values.

def true_or_false(default = true)
  puts 'calculate value ...'
  default
end

true_or_false
calculate value ...
=> true

true_or_false
=> true

true_or_false(true)
calculate value ...
=> true

Development

There are tests in spec. We only accept PRs with tests. To run tests:

  • Install Ruby 2.6.1
  • Install development dependencies using bundle install
  • Run tests using bundle exec rake current_rspec

We recommend to test large changes against multiple versions of Ruby. Supported combinations are configured in .github/workflows/test.yml. We provide some rake tasks to help with this:

  • Install development dependencies using bundle exec rake matrix:install
  • Run tests using bundle exec rake matrix:spec

Note that we have configured GitHub Actions to automatically run tests in all supported Ruby versions and dependency sets after each push. We will only merge pull requests after a green GitHub Actions run.

I'm very eager to keep this gem leightweight and on topic. If you're unsure whether a change would make it into the gem, talk to me beforehand.

License

See LICENSE.txt

Credits