Fixture not showing up in a Rails test

I have the following test for the login controller (I guess it could go anywhere?):

 test "Correct email must find user" do
    u = User.where(email: 'test@email.com').first
    puts "\n\n#{u}\n\n"
    assert false
  end

Here's test/fixtures/users.yml:

one:
  email: 'test@email.com'
#
two: {}
#  column: value

Here's what happens when I run rake test:

LoginControllerTest: test_Correct_email_must_find_user
------------------------------------------------------
D, [2015-09-13T21:05:23.277218 #2735] DEBUG -- : MONGODB | Adding localhost:27017 to the cluster.
  test_Correct_email_must_find_user                              ERROR (0.01s)
KeyError:         KeyError: key not found: "primary"
            test/controllers/login_controller_test.rb:9:in `block in <class:LoginControllerTest>'