How to load fixtures one at a time in Rails 5

load_fixtures.rb

# When Rails loads fixtures, it does so via a big multi-insert. If there is something wrong with a 
# fixture, it's extremely difficult to find out _which_ fixture is wrong.
# This can be run in a binding.pry OR in a Rails console.

require "active_record/fixtures" 

all = fixture_set_names = Dir["spec/fixtures/**/*.yml"].map { |f| File.basename f, '.yml' }

all.each do |fix|
  puts fix; ActiveRecord::FixtureSet.create_fixtures("#{Rails.root}/spec/fixtures", [fix])
end