diff --git a/src/dateutils.spec.js b/src/dateutils.spec.js
index 3ee87d33b..261ee36e7 100644
--- a/src/dateutils.spec.js
+++ b/src/dateutils.spec.js
@@ -71,6 +71,22 @@ describe('dateutils', function () {
   });
 
   describe('isLTE()', function () {
+    it('a is undefined', function () {
+      const a = undefined;
+      const b = XDate(2014, 1, 20);
+      expect(isLTE(b, a)).toBe(undefined);
+    });
+
+    it('b is undefined', function () {
+      const a = XDate(2013, 12, 31);
+      const b = undefined;
+      expect(isLTE(b, a)).toBe(undefined);
+    });
+
+    it('both are undefined', function () {
+      expect(isLTE(undefined, undefined)).toBe(undefined);
+    });
+
     it('2014-01-20 >= 2013-12-31', function () {
       const a = XDate(2013, 12, 31);
       const b = XDate(2014, 1, 20);
@@ -98,6 +114,22 @@ describe('dateutils', function () {
   });
 
   describe('isGTE()', function () {
+    it('a is undefined', function () {
+      const a = undefined;
+      const b = XDate(2014, 1, 20);
+      expect(isGTE(b, a)).toBe(undefined);
+    });
+
+    it('b is undefined', function () {
+      const a = XDate(2013, 12, 31);
+      const b = undefined;
+      expect(isGTE(b, a)).toBe(undefined);
+    });
+
+    it('both are undefined', function () {
+      expect(isGTE(undefined, undefined)).toBe(undefined);
+    });
+
     it('2014-01-20 >= 2013-12-31', function () {
       const a = XDate(2013, 12, 31);
       const b = XDate(2014, 1, 20);
diff --git a/src/dateutils.ts b/src/dateutils.ts
index 815283dd6..14d427fca 100644
--- a/src/dateutils.ts
+++ b/src/dateutils.ts
@@ -78,11 +78,15 @@ export function isToday(date?: XDate | string) {
 }
 
 export function isGTE(a: XDate, b: XDate) {
-  return b.diffDays(a) > -1;
+  if (a && b) {
+    return b.diffDays(a) > -1;
+  }
 }
 
 export function isLTE(a: XDate, b: XDate) {
-  return a.diffDays(b) > -1;
+  if (a && b) {
+    return a.diffDays(b) > -1;
+  }
 }
 
 export function formatNumbers(date: any) {
diff --git a/src/interface.ts b/src/interface.ts
index 14ab054eb..055743bed 100644
--- a/src/interface.ts
+++ b/src/interface.ts
@@ -20,7 +20,7 @@ export function xdateToData(date: XDate | string) {
 }
 
 export function parseDate(d?: any) {
-  if (!d) {
+  if (d === undefined) {
     return;
   } else if (d.timestamp) {
     // conventional data timestamp
diff --git a/src/timeline/Timeline.tsx b/src/timeline/Timeline.tsx
index 4072096f5..e2140ce86 100644
--- a/src/timeline/Timeline.tsx
+++ b/src/timeline/Timeline.tsx
@@ -265,6 +265,7 @@ const Timeline = (props: TimelineProps) => {
         width={width}
         numberOfDays={numberOfDays}
         timelineLeftInset={timelineLeftInset}
+        testID={`${testID}.hours`}
       />
       {times(numberOfDays, renderTimelineDay)}
     </ScrollView>
diff --git a/src/timeline/TimelineHours.tsx b/src/timeline/TimelineHours.tsx
index 2bec2cacc..f0366d6f9 100644
--- a/src/timeline/TimelineHours.tsx
+++ b/src/timeline/TimelineHours.tsx
@@ -27,6 +27,7 @@ export interface TimelineHoursProps {
   width: number;
   numberOfDays: number;
   timelineLeftInset?: number;
+  testID?: string;
 }
 
 const dimensionWidth = constants.screenWidth;
@@ -45,7 +46,8 @@ const TimelineHours = (props: TimelineHoursProps) => {
     onBackgroundLongPressOut,
     width,
     numberOfDays = 1,
-    timelineLeftInset = 0
+    timelineLeftInset = 0,
+    testID,
   } = props;
 
   const lastLongPressEventTime = useRef<NewEventTime>();
@@ -121,12 +123,14 @@ const TimelineHours = (props: TimelineHoursProps) => {
             {time === start ? null : (
               <View
                 key={`line${time}`}
+                testID={`${testID}.${time}.line`}
                 style={[styles.line, {top: offset * index, width: dimensionWidth - EVENT_DIFF, left: timelineLeftInset - 16}]}
               />
             )}
             {
               <View
                 key={`lineHalf${time}`}
+                testID={`${testID}.${time}.lineHalf`}
                 style={[styles.line, {top: offset * (index + 0.5), width: dimensionWidth - EVENT_DIFF, left: timelineLeftInset - 16}]}
               />
             }