Speed up your unit tests - heartcombo/devise GitHub Wiki

Note: this setting is now provided by default!

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In your configuration (devise.rb initializer), set the number of stretches to 1 for your test environment:

config.stretches = Rails.env.test? ? 1 : 10

This will increase performance dramatically if you use bcrypt and create a lot of users (e.g. if you use Factory Bot or Machinist).

Key stretching is a method of improving the security of passwords at the expense of speed. In the test environment, we are more concerned about speed than people trying to hack the passwords in the test database, so we turn the number of stretches down to 1.