```ruby
require 'test_helper'

class SimpleFormGeneratorTest < Rails::Generators::TestCase
  tests SimpleForm::Generators::InstallGenerator
  destination File.expand_path('../../tmp', __FILE__)
  setup :prepare_destination

  test 'generates example locale file' do
    run_generator
    assert_file 'config/locales/simple_form.en.yml'
  end

  test 'generates the simple_form initializer' do
    run_generator
    assert_file 'config/initializers/simple_form.rb'
  end

  test 'generates the simple_form initializer with the bootstrap wrappers' do
    run_generator %w(--bootstrap)
    assert_file 'config/initializers/simple_form.rb', /config\.wrappers :bootstrap/, /config\.default_wrapper = :bootstrap/
  end

  %W(erb haml slim).each do |engine|
    test "generates the scaffold template when using #{engine}" do
      run_generator ['-e', engine]
      assert_file "lib/templates/#{engine}/scaffold/_form.html.#{engine}"
    end
  end
end```

Remove test/tmp dir after running generator tests
user
```ruby
require 'test_helper'

class SimpleFormGeneratorTest < Rails::Generators::TestCase
  tests SimpleForm::Generators::InstallGenerator
  destination File.expand_path('../../tmp', __FILE__)
  setup :prepare_destination
  teardown { rm_rf(destination_root) }

  test 'generates example locale file' do
    run_generator
    assert_file 'config/locales/simple_form.en.yml'
  end

  test 'generates the simple_form initializer' do
    run_generator
    assert_file 'config/initializers/simple_form.rb'
  end

  test 'generates the simple_form initializer with the bootstrap wrappers' do
    run_generator %w(--bootstrap)
    assert_file 'config/initializers/simple_form.rb', /config\.wrappers :bootstrap/, /config\.default_wrapper = :bootstrap/
  end

  %W(erb haml slim).each do |engine|
    test "generates the scaffold template when using #{engine}" do
      run_generator ['-e', engine]
      assert_file "lib/templates/#{engine}/scaffold/_form.html.#{engine}"
    end
  end
end
```
assistant