Guatemala has a lab test.
Test 'kits' as such are said to retail for around $3000. The CDC is aiming to release (a potentially less accurate) one soon for $40.
Germany is testing live people, so Germany is detecting more asymptomatic spreaders, and thus has an apparently lower overall mortality rate.
Italy is conducting post-mortem tests and thus finding that more people have died from covid-19 complications than they might otherwise have been aware of. Hence in part their notably higher death rate.
The key thing about testing is that it allows one to acquire an understanding of how widespread the infection may have already spread in the general population, and hence how important it is to maintain the lockdown.
Otherwise it's just guesswork.