The test framework returns the location for a test so that an editor can jump to it when the user clicks on it. For tests that use testWidgets it returns the location of the test call inside testWidgets so it won't take the user to where they expect.

Example:

{
	"test": {
		"id": 3,
		"name": "Changing locale",
		"suiteID": 0,
		"groupIDs": [
			2
		],
		"line": 60,
		"column": 18,
		"url": "package:flutter_test/src/widget_tester.dart"
	},
	"type": "testStart",
	"time": 21952
}

I need to use this information to navigate to the test when a user clicks in the tree on the left. Currently I ignore any package: URIs so it just does nothing, but it makes the test runner much less useful.