testCompleted event should contain file path

If I run elm-test --report json elm-test will find all files in my test folder and run them.

Unfortunatly the testCompleted event, doesn't let us know which file it is from.

{
  "event": "testCompleted",
  "status": "fail",
  "labels": [
    "RoutingTests",
    "Route.fromUrl",
    "Parsing hash: \"#login\""
  ],
  "failures": [
    {
      "given": null,
      "message": "Expect.equal",
      "reason": {
        "type": "Equality",
        "data": {
          "expected": "Just Login",
          "actual": "Nothing",
          "comparison": "Expect.equal"
        }
      }
    }
  ],
  "duration": "3"
}

Start by tracing where the JSON output for the testCompleted event is assembled when running elm-test --report json. Compare the event data with the test files discovered by the runner, then verify that each event includes its source file path and that the existing JSON report output remains valid.