The person described in that Vox article - upper respiratory symptoms, no direct contact with someone with confirmed Covid-19 - wouldn't meet the criteria for testing anywhere that I know of off-hand. Certainly not in the UK or Australia, probably not in South Korea (though they allow people who don't qualify to buy testing out of pocket), not in a whole bunch of EU states, and Italy has much bigger things to worry about. Maybe in the more urban parts of China?
The community spread by this point has hit the entire US surely. They can't track every single confirmed person location-by-location because it's been far too long.
You are wrong about South Korea. Their testing has been incredibly effective from the beginning, patient 31 in South Korea had no known contact and was told to take a CV test by her doctors, but didn't take the advice until a 2 days later.
https://graphics.reuters.com/CHINA-HEALTH-SOUTHKOREA-CLUSTER...
In my country, you get tested even if you haven't had direct contact with confirmed COVID19, but have the symptoms and have travelled to selected countries or states in the last 4 weeks.
as a non-US person, the US can do much more than testing, (which is what most other countries can do). A cure, or a quick vaccine is what matters, testing is just a measure of how bad you are performing. Containment measures are necessary, and they work, but eventually we ll all get the virus, in a vaccine or not