If you've got to use fixtures, the least you can do is make sure they're actually valid.

fixtures_test.rb

require 'test_helper'

class FixturesTest < ActiveSupport::TestCase
  fixtures(:all).each do |fixture|
    define_method("test: #{fixture} is valid") do
      fixture_instances = @loaded_fixtures[fixture]

      invalid_fixtures = fixture_instances.keys.select do |fixture_name|
        !fixture_instances[fixture_name].find.valid?
      end

      assert_equal 0, invalid_fixtures.length, "Expected #{fixture} fixtures to be valid, but #{invalid_fixtures.to_sentence} #{invalid_fixtures.length == 1 ? "is" : "are"} not."
    end
  end
end