In mountable plugin fixtures from test/dummy/test/fixtures don't load

[yuriihabrusiev]

Steps to reproduce

1. Generate new mountable plugin with rails plugin new cool_plugin --mountable
2. Go to test/dummy and generate few scaffolds
3. Return to plugin root and run bin/rails t

Expected behavior

Tests should pass

Actual behavior

Tests don't pass because in test helper we have

if ActiveSupport::TestCase.respond_to?(:fixture_path=)
  ActiveSupport::TestCase.fixture_path = File.expand_path("../fixtures", __FILE__)
  ...
end

Potential solution

Change

ActiveSupport::TestCase.fixture_path = File.expand_path("../fixtures", __FILE__)

to

ActiveSupport::TestCase.fixture_path = File.expand_path("../dummy/test/fixtures", __FILE__)

in railties/lib/rails/generators/rails/plugin/templates/test/test_helper.rb

System configuration

Rails version: 5.0.0.rc2

Ruby version: 2.3.0

[maclover7]

Would you be willing to submit a PR to change this? We can continue the discussion there :)