database_resetter.rb

if Rails.env.test?
  require 'active_record/fixtures'
  require File.expand_path('../../test/config/geocoder.rb', __FILE__)

  DatabaseCleaner.strategy = :transaction

  class DatabaseResetter
    def self.start
      DatabaseCleaner.start

      # Reload the fixtures
      fixtures_path = File.join Rails.root, 'test', 'fixtures'
      ActiveRecord::FixtureSet.reset_cache
      Dir["#{fixtures_path}/**/*.yml"].map {|f| f[(fixtures_path.size + 1)..-5] }.each { |f_name| ActiveRecord::FixtureSet.create_fixtures(fixtures_path, f_name) }
    end

    def self.stop(controller)
      controller.session.delete :identity_id
      DatabaseCleaner.clean
    end
  end
end

routes.rb

namespace :api do
  if Rails.env.test?
    post '/tests' => 'tests#create'
    delete '/tests' => 'tests#destroy'
  end
end

tests_controller.rb

require 'database_resetter'

class Api::TestsController < ApplicationController
  before_action :ensure_test

  layout false

  def create
    DatabaseResetter.start
    head(:ok)
  end

  def destroy
    DatabaseResetter.stop(self)
    head(:ok)
  end

  private

  def ensure_test
    raise unless Rails.env.test?
  end
end