rework resolveTimestamps validation to fix test

We need a safe way to mark that validation fails in this function, without actually throwing an error. Let's use a third parameter for this purpose which is a callback function 'onFail' to handle the invalid case.
- Updated tests accordingly - now passing

www/__tests__/enketoHelper.test.ts

@@ -87,25 +87,25 @@ it('resolves the timestamps', () => {
   const missingData =
     '<tag> <Start_date>2016-08-28</Start_date> <End_date>2016-07-25</End_date> <End_time>17:30:31.000-06:00</End_time> </tag>';
   const missDataDoc = xmlParser.parseFromString(missingData, 'text/html');
-  expect(resolveTimestamps(missDataDoc, timelineEntry)).toBeNull();
+  expect(resolveTimestamps(missDataDoc, timelineEntry, () => {})).toBeNull();
   //bad time returns undefined
   const badTimes =
     '<tag> <Start_date>2016-08-28</Start_date> <End_date>2016-07-25</End_date> <Start_time>17:32:32.928-06:00</Start_time> <End_time>17:30:31.000-06:00</End_time> </tag>';
   const badTimeDoc = xmlParser.parseFromString(badTimes, 'text/xml');
-  expect(resolveTimestamps(badTimeDoc, timelineEntry)).toBeUndefined();
+  expect(resolveTimestamps(badTimeDoc, timelineEntry, () => {})).toBeUndefined();
   //if within a minute, timelineEntry timestamps
   const timeEntry =
     '<tag> <Start_date>2016-07-25</Start_date> <End_date>2016-07-25</End_date> <Start_time>17:24:32.928-06:00</Start_time> <End_time>17:30:31.000-06:00</End_time> </tag>';
   const xmlDoc1 = xmlParser.parseFromString(timeEntry, 'text/xml');
-  expect(resolveTimestamps(xmlDoc1, timelineEntry)).toMatchObject({
+  expect(resolveTimestamps(xmlDoc1, timelineEntry, () => {})).toMatchObject({
     start_ts: 1469492672.928242,
     end_ts: 1469493031,
   });
   // else survey timestamps
   const timeSurvey =
     '<tag> <Start_date>2016-07-25</Start_date> <End_date>2016-07-25</End_date> <Start_time>17:22:33.928-06:00</Start_time> <End_time>17:33:33.000-06:00</End_time> </tag>';
   const xmlDoc2 = xmlParser.parseFromString(timeSurvey, 'text/xml');
-  expect(resolveTimestamps(xmlDoc2, timelineEntry)).toMatchObject({
+  expect(resolveTimestamps(xmlDoc2, timelineEntry, () => {})).toMatchObject({
     start_ts: 1469492553.928,
     end_ts: 1469493213,
   });
@@ -205,7 +205,7 @@ it('resolves the label, if no labelVars, returns template', async () => {
  * @returns Promise of the saved result, or an Error if there was a problem
  */
 //   export function saveResponse(surveyName: string, enketoForm: Form, appConfig, opts: SurveyOptions) {
-it('gets the saved result or throws an error', () => {
+it('gets the saved result or throws an error', async () => {
   const surveyName = 'TimeUseSurvey';
   const form = {
     getDataStr: () => {
@@ -251,10 +251,9 @@ it('gets the saved result or throws an error', () => {
     label: '1 Personal Care',
     name: 'TimeUseSurvey',
   });
-  expect(saveResponse(surveyName, badForm, config, opts)).resolves.toMatchObject({
-    message:
-      'The times you entered are invalid. Please ensure that the start time is before the end time.',
-  });
+  expect(async () => await saveResponse(surveyName, badForm, config, opts)).rejects.toEqual(
+    'The times you entered are invalid. Please ensure that the start time is before the end time.',
+  );
 });
 
 /*

www/js/survey/enketo/enketoHelper.ts

@@ -169,10 +169,15 @@ export function getInstanceStr(xmlModel: string, opts?: SurveyOptions): string |
  * resolve timestamps label from the survey response
  * @param {XMLDocument} xmlDoc survey response as XML object
  * @param {object} timelineEntry trip or place object
+ * @param {function} onFail callback function to be called if timestamp validation fails
  * @returns {object} object with `start_ts` and `end_ts`
  *    - null if no timestamps are resolved
  */
-export function resolveTimestamps(xmlDoc: XMLDocument, timelineEntry: TimelineEntry) {
+export function resolveTimestamps(
+  xmlDoc: XMLDocument,
+  timelineEntry: TimelineEntry,
+  onFail: (e: Error) => void,
+) {
   // check for Date and Time fields
   const startDate = xmlDoc.getElementsByTagName('Start_date')?.[0]?.innerHTML;
   let startTime = xmlDoc.getElementsByTagName('Start_time')?.[0]?.innerHTML;
@@ -197,7 +202,8 @@ export function resolveTimestamps(xmlDoc: XMLDocument, timelineEntry: TimelineEn
   let additionEndTs = DateTime.fromISO(endDate + 'T' + endTime, { zone: timezone }).toSeconds();
 
   if (additionStartTs > additionEndTs) {
-    throw new Error(i18next.t('survey.enketo-timestamps-invalid')); //"Timestamps are invalid. Please ensure that the start time is before the end time.");
+    onFail(new Error(i18next.t('survey.enketo-timestamps-invalid'))); //"Timestamps are invalid. Please ensure that the start time is before the end time.");
+    return;
   }
 
   /* Enketo survey time inputs are only precise to the minute, while trips/places are precise to
@@ -243,7 +249,9 @@ export function saveResponse(
       let timestamps: TimestampRange | { ts: number; fmt_time: string } | undefined;
       let match_id: string | undefined;
       if (opts?.timelineEntry) {
-        const resolvedTimestamps = resolveTimestamps(xmlDoc, opts.timelineEntry);
+        const resolvedTimestamps = resolveTimestamps(xmlDoc, opts.timelineEntry, (errOnFail) => {
+          return Promise.reject(errOnFail);
+        });
         if (resolvedTimestamps?.start_ts && resolvedTimestamps?.end_ts) {
           timestamps = resolvedTimestamps;
         } else {
@@ -257,7 +265,6 @@ export function saveResponse(
               : opts.timelineEntry.exit_ts,
           };
         }
-
         // UUID generated using this method https://stackoverflow.com/a/66332305
         match_id = URL.createObjectURL(new Blob([])).slice(-36);
       } else {