As COVID-19 testing demand surges across Penobscot County amid the rapid spread of the delta variant, residents are finding it harder to book appointments for virus tests and seeing longer wait times for results, especially if they are not symptomatic. More than 13,000 COVID-19 tests were done in Penobscot County in the two weeks leading up to Thursday, a rate that is 15 percent higher than the rest of Maine, according to Maine Center for Disease Control data.