```ruby
require 'test_helper'

class MongoMapperTest < Test::Unit::TestCase

  context "The MongoMapper extension" do
    setup do
      setup_fixtures
      @person = MongoMapperPerson.create
    end

    should "be able to find the object in the database" do
      assert_equal @person, MongoMapperPerson._t_find(@person.id)
    end

    should "be able to find the associates of an object" do
      person_1 = MongoMapperPerson.create(:active_record_account_id => 101)
      person_2 = MongoMapperPerson.create(:active_record_account_id => 101)
      person_3 = MongoMapperPerson.create(:active_record_account_id => 102)
      assert_set_equal [person_1, person_2], MongoMapperPerson._t_find_all_by_associate(:active_record_account_id, 101)
    end

    should "be able to associate many objects with the given object" do
    end

    should "be able to get the ids of the objects associated with the given object" do
    end
  end

end
```

Add a few more mongo mapper extension tests
user
```ruby
require 'test_helper'

class MongoMapperTest < Test::Unit::TestCase

  context "The MongoMapper extension" do
    setup do
      setup_fixtures
    end

    should "be able to find the object in the database" do
      person = MongoMapperPerson.create
      assert_equal person, MongoMapperPerson._t_find(person.id)
    end

    should "be able to find the associates of an object" do
      person_1 = MongoMapperPerson.create(:active_record_account_id => 101)
      person_2 = MongoMapperPerson.create(:active_record_account_id => 101)
      person_3 = MongoMapperPerson.create(:active_record_account_id => 102)
      assert_set_equal [person_1, person_2], MongoMapperPerson._t_find_all_by_associate(:active_record_account_id, 101)
    end

    should "be able to associate many objects with the given object" do
      transaction_1 = ActiveRecordTransaction.create
      transaction_2 = ActiveRecordTransaction.create
      transaction_3 = ActiveRecordTransaction.create
      person = MongoMapperPerson.create
      person._t_associate_many(:active_record_transactions, [transaction_1.id, transaction_2.id, transaction_3.id])
      assert_set_equal [transaction_1.id, transaction_2.id, transaction_3.id], person._t_active_record_transaction_ids
    end

    should "be able to get the ids of the objects associated with the given object" do
      transaction_1 = ActiveRecordTransaction.create
      transaction_2 = ActiveRecordTransaction.create
      transaction_3 = ActiveRecordTransaction.create
      person = MongoMapperPerson.create
      person._t_associate_many(:active_record_transactions, [transaction_1.id, transaction_2.id, transaction_3.id])
      assert_set_equal [transaction_1.id, transaction_2.id, transaction_3.id], person._t_get_associate_ids(:active_record_transactions)
    end
  end

end
```
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