```ruby
begin
  gem 'minitest'
rescue LoadError
end

require 'active_model'
require 'format_validator'
require 'minitest/autorun'
```

Change the name active_model to activemodel
user
```ruby
begin
  gem 'minitest'
rescue LoadError
end

require 'activemodel'
require 'format_validator'
require 'minitest/autorun'
```
assistant