My test\_helper.rb looked like this:
```ruby
require 'minitest/autorun'
require 'app'
```
The output when running a unit test was this:
```ruby
0 tests, 0 assertions, 0 failures, 0 errors
```
The solution was to move the minitest require:
```ruby
require 'minitest/autorun'
require 'app'
```
Now my tests are run again when executing:
```ruby
ruby test/functional/xxx_controller_test.rb
```