How to configure minitest for performance and manually create / delete fixtures

Question

How to configure minitest for performance and manually create / delete fixtures

My problems:

The client database is located in the machine through the VPN, so my tests are very slow (about 30-40 seconds each)
This database is not completely suitable for my application, and my data is associated with data that was already in the database
Composite primary keys are present in old database tables, and informix adapter does not support it for fixtures

What I use:

Ruby on Rails 4.2.5
Jruby 9.0.1.0
Informix Database Through JDBC Connection
Minitest
MiniTest-o

What i have done so far:

Testing time was reduced after 5-10 seconds with Devise.stretches = 1and configurations Rails.logger.level = 4.
fixture , , , , , . , .
, , (self.use_transactional_fixtures = false), , , .

reset " " , , , , , . " ", :

class ActiveRecord::FixtureSet
  class << self
    alias :orig_create_fixtures :create_fixtures
  end

  def self.create_fixtures f_dir, fs_names, *args
    reset_cache

    #Deleting my fixture data
    People.delete_all

    orig_create_fixtures f_dir, fs_names, *args
  end
end

delete_all .

, , 8 .

:

ENV["RAILS_ENV"] = "test"
require File.expand_path('../../config/environment', __FILE__)
require "rails/test_help"
require 'minitest/autorun'
require 'minitest/reporters'

Minitest.backtrace_filter = Minitest::BacktraceFilter.new

# Load support files
Dir["#{File.dirname(__FILE__)}/support/**/*.rb"].each { |f| require f }

ActiveSupport::TestCase.class_eval do
  extend MiniTest::Spec::DSL

  # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
  fixtures :all

  self.use_transactional_fixtures = false

  Devise.stretches = 1
  Rails.logger.level = 4

  reporter_options = {color: true, slow_count: 5}
  Minitest::Reporters.use! [Minitest::Reporters::DefaultReporter.new(reporter_options)]
end