Why did she get a test?
What is the point?
Presumably it was a precaution. It sounds like she and Don Jr. were going to join President Trump at the event. People who are going to be interacting with POTUS are routinely tested nowadays as a precaution so he doesn’t catch it.
Being tested is mandatory if you’re going to be close to the president. Just by being 74 years old puts the president in a high risk group.