The memory_test_fix rails plugin, as a gem


A simple fix to run your Rails tests with sqlite. From the example by Chris Roos.


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Add the gem to your bundle by adding

gem 'memory_test_fix'

to your Gemfile.

In your database.yml, use:

  adapter: sqlite3
  database: ":memory:"

It runs much faster!

You can also adjust the verbosity of the output:

  adapter: sqlite3
  database: ":memory:"
  verbosity: silent

To use rails migrations instead of loading db/schema.rb

  adapter: sqlite3
  database: ":memory:"
  migrate: true

You can also use this with other (testing) environments, not just 'test'.

Rails Versions

In general, Bundler should pick a compatible version for you if you don't specify one in your Gemfile.

That said, the latest version of this gem is compatible with Rails 5.0. If you're still on Rails 4, you can use version 1.3.0. Unfortunately, the hard requirement of Ruby 2.2 or above for Rails 5 means memory_test_fix cannot support Rails 4 and 5 at the same time.

If you're using a version of Rails older than 4, your first priority should be upgrading Rails. If that's really not an option, you can use version 1.2.2 of this gem with Rails 3.2. If you're using Rails 3.1 or 3.0, use version 1.1.0. If you're using Rails 2.3, use version 0.2.2. If you're using an even older version of Rails, use version 0.1.3.


The original hack this gem is based on was created by Chris Roos.

The hack was adapted as a Rails plugin by Geoffrey Grosenbach.

The following people have contributed:

  • Kakutani Shintaro
  • Matijs van Zuijlen
  • Erik Hanson & Matt Scilipoti
  • Greg Weber
  • Stephan Zalewski

MemoryTestFix is maintained by Matijs van Zuijlen