diff --git a/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-day.js b/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-day.js
index acd15f04db..9b43411db3 100644
--- a/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-day.js
+++ b/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-day.js
@@ -3,7 +3,7 @@
 
 /*---
 esid: sec-temporal.calendar.prototype.dateuntil
-description: Temporal.Calendar.prototype.dateUntil with largestUnit === "day"
+description: Temporal.Calendar.prototype.dateUntil with largestUnit: "day"
 info: |
   1. Let calendar be the this value.
   2. Perform ? RequireInternalSlot(calendar, [[InitializedTemporalCalendar]]).
@@ -15,28 +15,45 @@ info: |
   8. Let result be ! DifferenceISODate(one.[[ISOYear]], one.[[ISOMonth]], one.[[ISODay]], two.[[ISOYear]], two.[[ISOMonth]], two.[[ISODay]], largestUnit).
   9. Return ? CreateTemporalDuration(result.[[Years]], result.[[Months]], result.[[Weeks]], result.[[Days]], 0, 0, 0, 0, 0, 0).
 features: [Temporal]
+includes: [temporalHelpers.js]
 ---*/
 let cal = new Temporal.Calendar("iso8601");
 
 ["day", "days"].forEach(function(largestUnit) {
   let opt = {largestUnit};
-  assert.sameValue("PT0S", cal.dateUntil("2021-07-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("P1D", cal.dateUntil("2021-07-16", "2021-07-17", opt).toJSON());
-  assert.sameValue("P32D", cal.dateUntil("2021-07-16", "2021-08-17", opt).toJSON());
-  assert.sameValue("P62D", cal.dateUntil("2021-07-16", "2021-09-16", opt).toJSON());
-  assert.sameValue("P365D",
-      cal.dateUntil("2021-07-16", "2022-07-16", opt).toJSON());
-  assert.sameValue("P3652D"
-      ,cal.dateUntil("2021-07-16", "2031-07-16", opt).toJSON());
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-16", opt),
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, "same day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-17", opt),
+      0, 0, 0, 1, 0, 0, 0, 0, 0, 0, "one day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-08-17", opt),
+      0, 0, 0, 32, 0, 0, 0, 0, 0, 0, "32 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-09-16", opt),
+      0, 0, 0, 62, 0, 0, 0, 0, 0, 0, "62 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2022-07-16", opt),
+      0, 0, 0, 365, 0, 0, 0, 0, 0, 0, "365 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2031-07-16", opt),
+      0, 0, 0, 3652, 0, 0, 0, 0, 0, 0, "3652 days");
 
-  assert.sameValue("-P1D",
-      cal.dateUntil("2021-07-17", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P32D",
-      cal.dateUntil("2021-08-17", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P62D",
-      cal.dateUntil("2021-09-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P365D",
-      cal.dateUntil("2022-07-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P3652D",
-      cal.dateUntil("2031-07-16", "2021-07-16", opt).toJSON());
+
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-17", "2021-07-16", opt),
+      0, 0, 0, -1, 0, 0, 0, 0, 0, 0, "negative one day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-08-17", "2021-07-16", opt),
+      0, 0, 0, -32, 0, 0, 0, 0, 0, 0, "negative 32 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-09-16", "2021-07-16", opt),
+      0, 0, 0, -62, 0, 0, 0, 0, 0, 0, "negative 62 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2022-07-16", "2021-07-16", opt),
+      0, 0, 0, -365, 0, 0, 0, 0, 0, 0, "negative 365 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2031-07-16", "2021-07-16", opt),
+      0, 0, 0, -3652, 0, 0, 0, 0, 0, 0, "negative 3652 days");
 });
diff --git a/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-month.js b/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-month.js
index 79571e26a3..fa055aa35c 100644
--- a/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-month.js
+++ b/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-month.js
@@ -3,7 +3,7 @@
 
 /*---
 esid: sec-temporal.calendar.prototype.dateuntil
-description: Temporal.Calendar.prototype.dateUntil with largestUnit === "month"
+description: Temporal.Calendar.prototype.dateUntil with largestUnit: "month"
 info: |
   1. Let calendar be the this value.
   2. Perform ? RequireInternalSlot(calendar, [[InitializedTemporalCalendar]]).
@@ -15,44 +15,80 @@ info: |
   8. Let result be ! DifferenceISODate(one.[[ISOYear]], one.[[ISOMonth]], one.[[ISODay]], two.[[ISOYear]], two.[[ISOMonth]], two.[[ISODay]], largestUnit).
   9. Return ? CreateTemporalDuration(result.[[Years]], result.[[Months]], result.[[Weeks]], result.[[Days]], 0, 0, 0, 0, 0, 0).
 features: [Temporal]
+includes: [temporalHelpers.js]
 ---*/
 let cal = new Temporal.Calendar("iso8601");
 
 ["month", "months"].forEach(function(largestUnit) {
   let opt = {largestUnit};
-  assert.sameValue("PT0S", cal.dateUntil("2021-07-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("P1D", cal.dateUntil("2021-07-16", "2021-07-17", opt).toJSON());
-  assert.sameValue("P7D", cal.dateUntil("2021-07-16", "2021-07-23", opt).toJSON());
-  assert.sameValue("P1M", cal.dateUntil("2021-07-16", "2021-08-16", opt).toJSON());
-  assert.sameValue("P1M", cal.dateUntil("2020-12-16", "2021-01-16", opt).toJSON());
-  assert.sameValue("P1M", cal.dateUntil("2021-01-05", "2021-02-05", opt).toJSON());
-  assert.sameValue("P2M", cal.dateUntil("2021-01-07", "2021-03-07", opt).toJSON());
-  assert.sameValue("P1M1D", cal.dateUntil("2021-07-16", "2021-08-17", opt).toJSON());
-  assert.sameValue("P28D", cal.dateUntil("2021-07-16", "2021-08-13", opt).toJSON());
-  assert.sameValue("P2M", cal.dateUntil("2021-07-16", "2021-09-16", opt).toJSON());
-  assert.sameValue("P12M",
-      cal.dateUntil("2021-07-16", "2022-07-16", opt).toJSON());
-  assert.sameValue("P120M"
-      ,cal.dateUntil("2021-07-16", "2031-07-16", opt).toJSON());
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-16", opt),
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, "same day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-17", opt),
+      0, 0, 0, 1, 0, 0, 0, 0, 0, 0, "one day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-23", opt),
+      0, 0, 0, 7, 0, 0, 0, 0, 0, 0, "7 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-08-16", opt),
+      0, 1, 0, 0, 0, 0, 0, 0, 0, 0, "1 month in same year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2020-12-16", "2021-01-16", opt),
+      0, 1, 0, 0, 0, 0, 0, 0, 0, 0, "1 month in different year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-01-05", "2021-02-05", opt),
+      0, 1, 0, 0, 0, 0, 0, 0, 0, 0, "1 month in same year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-01-07", "2021-03-07", opt),
+      0, 2, 0, 0, 0, 0, 0, 0, 0, 0, "2 month in same year across Feb 28");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-08-17", opt),
+      0, 1, 0, 1, 0, 0, 0, 0, 0, 0, "1 month and 1 day in a month with 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-08-13", opt),
+      0, 0, 0, 28, 0, 0, 0, 0, 0, 0, "28 days roll across a month which has 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-09-16", opt),
+      0, 2, 0, 0, 0, 0, 0, 0, 0, 0, "2 months with both months which have 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2022-07-16", opt),
+      0, 12, 0, 0, 0, 0, 0, 0, 0, 0, "12 months");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2031-07-16", opt),
+      0, 120, 0, 0, 0, 0, 0, 0, 0, 0, "120 months");
 
-  assert.sameValue("-P1D",
-      cal.dateUntil("2021-07-17", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P1M1D",
-      cal.dateUntil("2021-08-17", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P28D",
-      cal.dateUntil("2021-08-13", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P1M",
-      cal.dateUntil("2021-08-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P1M3D",
-      cal.dateUntil("2021-08-16", "2021-07-13", opt).toJSON());
-  assert.sameValue("-P2M",
-      cal.dateUntil("2021-09-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P2M5D",
-      cal.dateUntil("2021-09-21", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P12M",
-      cal.dateUntil("2022-07-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P12M1D",
-      cal.dateUntil("2022-07-17", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P120M",
-      cal.dateUntil("2031-07-16", "2021-07-16", opt).toJSON());
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-17", "2021-07-16", opt),
+      0, 0, 0, -1, 0, 0, 0, 0, 0, 0, "negative one day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-23", "2021-07-16", opt),
+      0, 0, 0, -7, 0, 0, 0, 0, 0, 0, "negative 7 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-08-16", "2021-07-16", opt),
+      0, -1, 0, 0, 0, 0, 0, 0, 0, 0, "negative 1 month in same year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-01-16", "2020-12-16", opt),
+      0, -1, 0, 0, 0, 0, 0, 0, 0, 0, "negative 1 month in different year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-02-05", "2021-01-05", opt),
+      0, -1, 0, 0, 0, 0, 0, 0, 0, 0, "negative 1 month in same year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-03-07", "2021-01-07", opt),
+      0, -2, 0, 0, 0, 0, 0, 0, 0, 0, "negative 2 month in same year across Feb 28");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-08-17", "2021-07-16", opt),
+      0, -1, 0, -1, 0, 0, 0, 0, 0, 0, "negative 1 month and 1 day in a month with 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-08-13", "2021-07-16", opt),
+      0, 0, 0, -28, 0, 0, 0, 0, 0, 0, "negative 28 days roll across a month which has 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-09-16", "2021-07-16", opt),
+      0, -2, 0, 0, 0, 0, 0, 0, 0, 0, "negative 2 months with both months which have 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2022-07-16", "2021-07-16", opt),
+      0, -12, 0, 0, 0, 0, 0, 0, 0, 0, "negative 12 months");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2031-07-16", "2021-07-16", opt),
+      0, -120, 0, 0, 0, 0, 0, 0, 0, 0, "negative 120 months");
 });
diff --git a/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-week.js b/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-week.js
index 562633a32c..12031ec319 100644
--- a/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-week.js
+++ b/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-week.js
@@ -3,7 +3,7 @@
 
 /*---
 esid: sec-temporal.calendar.prototype.dateuntil
-description: Temporal.Calendar.prototype.dateUntil with largestUnit === "week"
+description: Temporal.Calendar.prototype.dateUntil with largestUnit: "week"
 info: |
   1. Let calendar be the this value.
   2. Perform ? RequireInternalSlot(calendar, [[InitializedTemporalCalendar]]).
@@ -15,32 +15,57 @@ info: |
   8. Let result be ! DifferenceISODate(one.[[ISOYear]], one.[[ISOMonth]], one.[[ISODay]], two.[[ISOYear]], two.[[ISOMonth]], two.[[ISODay]], largestUnit).
   9. Return ? CreateTemporalDuration(result.[[Years]], result.[[Months]], result.[[Weeks]], result.[[Days]], 0, 0, 0, 0, 0, 0).
 features: [Temporal]
+includes: [temporalHelpers.js]
 ---*/
 let cal = new Temporal.Calendar("iso8601");
 
 ["week", "weeks"].forEach(function(largestUnit) {
   let opt = {largestUnit};
-  assert.sameValue("PT0S", cal.dateUntil("2021-07-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("P1D", cal.dateUntil("2021-07-16", "2021-07-17", opt).toJSON());
-  assert.sameValue("P1W", cal.dateUntil("2021-07-16", "2021-07-23", opt).toJSON());
-  assert.sameValue("P4W4D", cal.dateUntil("2021-07-16", "2021-08-17", opt).toJSON());
-  assert.sameValue("P4W", cal.dateUntil("2021-07-16", "2021-08-13", opt).toJSON());
-  assert.sameValue("P8W6D", cal.dateUntil("2021-07-16", "2021-09-16", opt).toJSON());
-  assert.sameValue("P52W1D",
-      cal.dateUntil("2021-07-16", "2022-07-16", opt).toJSON());
-  assert.sameValue("P521W5D"
-      ,cal.dateUntil("2021-07-16", "2031-07-16", opt).toJSON());
 
-  assert.sameValue("-P1D",
-      cal.dateUntil("2021-07-17", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P4W4D",
-      cal.dateUntil("2021-08-17", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P4W",
-      cal.dateUntil("2021-08-13", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P8W6D",
-      cal.dateUntil("2021-09-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P52W1D",
-      cal.dateUntil("2022-07-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P521W5D",
-      cal.dateUntil("2031-07-16", "2021-07-16", opt).toJSON());
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-16", opt),
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, "same day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-17", opt),
+      0, 0, 0, 1, 0, 0, 0, 0, 0, 0, "one day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-23", opt),
+      0, 0, 1, 0, 0, 0, 0, 0, 0, 0, "7 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-08-16", opt),
+      0, 0, 4, 3, 0, 0, 0, 0, 0, 0, "4 weeks and 3 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-08-13", opt),
+      0, 0, 4, 0, 0, 0, 0, 0, 0, 0, "4 weeks");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-09-16", opt),
+      0, 0, 8, 6, 0, 0, 0, 0, 0, 0, "8 weeks and 6 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2022-07-16", opt),
+      0, 0, 52, 1, 0, 0, 0, 0, 0, 0, "52 weeks and 1 day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2031-07-16", opt),
+      0, 0, 521, 5, 0, 0, 0, 0, 0, 0, "521 weeks and 5 days");
+
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-17", "2021-07-16", opt),
+      0, 0, 0, -1, 0, 0, 0, 0, 0, 0, "negative one day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-23", "2021-07-16", opt),
+      0, 0, -1, 0, 0, 0, 0, 0, 0, 0, "negative 7 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-08-16", "2021-07-16", opt),
+      0, 0, -4, -3, 0, 0, 0, 0, 0, 0, "negative 4 weeks and 3 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-08-13", "2021-07-16", opt),
+      0, 0, -4, 0, 0, 0, 0, 0, 0, 0, "negative 4 weeks");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-09-16", "2021-07-16", opt),
+      0, 0, -8, -6, 0, 0, 0, 0, 0, 0, "negative 8 weeks and 6 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2022-07-16", "2021-07-16", opt),
+      0, 0, -52, -1, 0, 0, 0, 0, 0, 0, "negative 52 weeks and 1 day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2031-07-16", "2021-07-16", opt),
+      0, 0, -521, -5, 0, 0, 0, 0, 0, 0, "negative 521 weeks and 5 days");
 });
diff --git a/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-year.js b/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-year.js
index 8bb906a98b..c1a01c5669 100644
--- a/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-year.js
+++ b/test/built-ins/Temporal/Calendar/prototype/dateUntil/largest-unit-year.js
@@ -3,7 +3,7 @@
 
 /*---
 esid: sec-temporal.calendar.prototype.dateuntil
-description: Temporal.Calendar.prototype.dateUntil with largestUnit === "year"
+description: Temporal.Calendar.prototype.dateUntil with largestUnit: "year"
 info: |
   1. Let calendar be the this value.
   2. Perform ? RequireInternalSlot(calendar, [[InitializedTemporalCalendar]]).
@@ -15,110 +15,190 @@ info: |
   8. Let result be ! DifferenceISODate(one.[[ISOYear]], one.[[ISOMonth]], one.[[ISODay]], two.[[ISOYear]], two.[[ISOMonth]], two.[[ISODay]], largestUnit).
   9. Return ? CreateTemporalDuration(result.[[Years]], result.[[Months]], result.[[Weeks]], result.[[Days]], 0, 0, 0, 0, 0, 0).
 features: [Temporal]
+includes: [temporalHelpers.js]
 ---*/
 let cal = new Temporal.Calendar("iso8601");
 
 ["year", "years"].forEach(function(largestUnit) {
   let opt = {largestUnit};
-  assert.sameValue("PT0S", cal.dateUntil("2021-07-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("P1D", cal.dateUntil("2021-07-16", "2021-07-17", opt).toJSON());
-  assert.sameValue("P7D", cal.dateUntil("2021-07-16", "2021-07-23", opt).toJSON());
-  assert.sameValue("P1M", cal.dateUntil("2021-07-16", "2021-08-16", opt).toJSON());
-  assert.sameValue("P1M", cal.dateUntil("2020-12-16", "2021-01-16", opt).toJSON());
-  assert.sameValue("P1M", cal.dateUntil("2021-01-05", "2021-02-05", opt).toJSON());
-  assert.sameValue("P2M", cal.dateUntil("2021-01-07", "2021-03-07", opt).toJSON());
-  assert.sameValue("P1M1D", cal.dateUntil("2021-07-16", "2021-08-17", opt).toJSON());
-  assert.sameValue("P28D", cal.dateUntil("2021-07-16", "2021-08-13", opt).toJSON());
-  assert.sameValue("P2M", cal.dateUntil("2021-07-16", "2021-09-16", opt).toJSON());
-  assert.sameValue("P1Y",
-      cal.dateUntil("2021-07-16", "2022-07-16", opt).toJSON());
-  assert.sameValue("P1Y3D",
-      cal.dateUntil("2021-07-16", "2022-07-19", opt).toJSON());
-  assert.sameValue("P1Y2M3D",
-      cal.dateUntil("2021-07-16", "2022-09-19", opt).toJSON());
-  assert.sameValue("P10Y",
-      cal.dateUntil("2021-07-16", "2031-07-16", opt).toJSON());
-  assert.sameValue("P10Y5M",
-      cal.dateUntil("2021-07-16", "2031-12-16", opt).toJSON());
-  assert.sameValue("P23Y7M",
-      cal.dateUntil("1997-12-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("P24Y",
-      cal.dateUntil("1997-07-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("P23Y11M29D",
-      cal.dateUntil("1997-07-16", "2021-07-15", opt).toJSON());
-  assert.sameValue("P23Y11M30D",
-      cal.dateUntil("1997-06-16", "2021-06-15", opt).toJSON());
-  assert.sameValue("P60Y1M",
-      cal.dateUntil("1960-02-16", "2020-03-16", opt).toJSON());
-  assert.sameValue("P61Y27D",
-      cal.dateUntil("1960-02-16", "2021-03-15", opt).toJSON());
-  assert.sameValue("P60Y28D",
-      cal.dateUntil("1960-02-16", "2020-03-15", opt).toJSON());
+ TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-16", opt),
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, "same day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-17", opt),
+      0, 0, 0, 1, 0, 0, 0, 0, 0, 0, "one day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-23", opt),
+      0, 0, 0, 7, 0, 0, 0, 0, 0, 0, "7 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-08-16", opt),
+      0, 1, 0, 0, 0, 0, 0, 0, 0, 0, "1 month in same year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2020-12-16", "2021-01-16", opt),
+      0, 1, 0, 0, 0, 0, 0, 0, 0, 0, "1 month in different year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-01-05", "2021-02-05", opt),
+      0, 1, 0, 0, 0, 0, 0, 0, 0, 0, "1 month in same year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-01-07", "2021-03-07", opt),
+      0, 2, 0, 0, 0, 0, 0, 0, 0, 0, "2 month in same year across Feb 28");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-08-17", opt),
+      0, 1, 0, 1, 0, 0, 0, 0, 0, 0, "1 month and 1 day in a month with 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-08-13", opt),
+      0, 0, 0, 28, 0, 0, 0, 0, 0, 0, "28 days roll across a month which has 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-09-16", opt),
+      0, 2, 0, 0, 0, 0, 0, 0, 0, 0, "2 months with both months which have 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2022-07-16", opt),
+      1, 0, 0, 0, 0, 0, 0, 0, 0, 0, "1 year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2031-07-16", opt),
+      10, 0, 0, 0, 0, 0, 0, 0, 0, 0, "10 years");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2022-07-19", opt),
+      1, 0, 0, 3, 0, 0, 0, 0, 0, 0, "1 year and 3 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2022-09-19", opt),
+      1, 2, 0, 3, 0, 0, 0, 0, 0, 0, "1 year 2 months and 3 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2031-12-16", opt),
+      10, 5, 0, 0, 0, 0, 0, 0, 0, 0, "10 years and 5 months");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("1997-12-16", "2021-07-16", opt),
+      23, 7, 0, 0, 0, 0, 0, 0, 0, 0, "23 years and 7 months");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("1997-07-16", "2021-07-16", opt),
+      24, 0, 0, 0, 0, 0, 0, 0, 0, 0, "24 years");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("1997-07-16", "2021-07-15", opt),
+      23, 11, 0, 29, 0, 0, 0, 0, 0, 0, "23 years, 11 months and 29 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("1997-06-16", "2021-06-15", opt),
+      23, 11, 0, 30, 0, 0, 0, 0, 0, 0, "23 years, 11 months and 30 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("1960-02-16", "2020-03-16", opt),
+      60, 1, 0, 0, 0, 0, 0, 0, 0, 0, "60 years, 1 month");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("1960-02-16", "2021-03-15", opt),
+      61, 0, 0, 27, 0, 0, 0, 0, 0, 0, "61 years, 27 days in non leap year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("1960-02-16", "2020-03-15", opt),
+      60, 0, 0, 28, 0, 0, 0, 0, 0, 0, "60 years, 28 days in leap year");
 
-  assert.sameValue("P3M16D",
-      cal.dateUntil("2021-03-30", "2021-07-16", opt).toJSON());
-  assert.sameValue("P1Y3M16D",
-      cal.dateUntil("2020-03-30", "2021-07-16", opt).toJSON());
-  assert.sameValue("P61Y3M16D",
-      cal.dateUntil("1960-03-30", "2021-07-16", opt).toJSON());
-  assert.sameValue("P1Y6M16D",
-      cal.dateUntil("2019-12-30", "2021-07-16", opt).toJSON());
-  assert.sameValue("P6M16D",
-      cal.dateUntil("2020-12-30", "2021-07-16", opt).toJSON());
-  assert.sameValue("P23Y6M16D",
-      cal.dateUntil("1997-12-30", "2021-07-16", opt).toJSON());
-  assert.sameValue("P2019Y6M21D",
-      cal.dateUntil("0001-12-25", "2021-07-16", opt).toJSON());
-  assert.sameValue("P1Y2M5D",
-      cal.dateUntil("2019-12-30", "2021-03-05", opt).toJSON());
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-03-30", "2021-07-16", opt),
+      0, 3, 0, 16, 0, 0, 0, 0, 0, 0, "3 months and 16 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2020-03-30", "2021-07-16", opt),
+      1, 3, 0, 16, 0, 0, 0, 0, 0, 0, "1 year, 3 months and 16 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("1960-03-30", "2021-07-16", opt),
+      61, 3, 0, 16, 0, 0, 0, 0, 0, 0, "61 years, 3 months and 16 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2019-12-30", "2021-07-16", opt),
+      1, 6, 0, 16, 0, 0, 0, 0, 0, 0, "1 year, 6 months and 16 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2020-12-30", "2021-07-16", opt),
+      0, 6, 0, 16, 0, 0, 0, 0, 0, 0, "6 months and 16 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("1997-12-30", "2021-07-16", opt),
+      23, 6, 0, 16, 0, 0, 0, 0, 0, 0, "23 years, 6 months and 16 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("0001-12-25", "2021-07-16", opt),
+      2019, 6, 0, 21, 0, 0, 0, 0, 0, 0, "2019 years, 6 months and 21 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2019-12-30", "2021-03-05", opt),
+      1, 2, 0, 5, 0, 0, 0, 0, 0, 0, "1 year, 2 months and 5 days");
 
-  assert.sameValue("-P1D",
-      cal.dateUntil("2021-07-17", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P1M1D",
-      cal.dateUntil("2021-08-17", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P28D",
-      cal.dateUntil("2021-08-13", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P1M",
-      cal.dateUntil("2021-08-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P1M3D",
-      cal.dateUntil("2021-08-16", "2021-07-13", opt).toJSON());
-  assert.sameValue("-P2M",
-      cal.dateUntil("2021-09-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P2M5D",
-      cal.dateUntil("2021-09-21", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P1Y",
-      cal.dateUntil("2022-07-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P1Y1D",
-      cal.dateUntil("2022-07-17", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P1Y3M1D",
-      cal.dateUntil("2022-10-17", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P10Y",
-      cal.dateUntil("2031-07-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P10Y11M",
-      cal.dateUntil("2032-07-16", "2021-08-16", opt).toJSON());
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-17", "2021-07-16", opt),
+      0, 0, 0, -1, 0, 0, 0, 0, 0, 0, "negative one day");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-23", "2021-07-16", opt),
+      0, 0, 0, -7, 0, 0, 0, 0, 0, 0, "negative 7 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-08-16", "2021-07-16", opt),
+      0, -1, 0, 0, 0, 0, 0, 0, 0, 0, "negative 1 month in same year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-01-16", "2020-12-16", opt),
+      0, -1, 0, 0, 0, 0, 0, 0, 0, 0, "negative 1 month in different year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-02-05", "2021-01-05", opt),
+      0, -1, 0, 0, 0, 0, 0, 0, 0, 0, "negative 1 month in same year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-03-07", "2021-01-07", opt),
+      0, -2, 0, 0, 0, 0, 0, 0, 0, 0, "negative 2 month in same year across Feb 28");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-08-17", "2021-07-16", opt),
+      0, -1, 0, -1, 0, 0, 0, 0, 0, 0, "negative 1 month and 1 day in a month with 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-08-13", "2021-07-16", opt),
+      0, 0, 0, -28, 0, 0, 0, 0, 0, 0, "negative 28 days roll across a month which has 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-09-16", "2021-07-16", opt),
+      0, -2, 0, 0, 0, 0, 0, 0, 0, 0, "negative 2 months with both months which have 31 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2022-07-16", "2021-07-16", opt),
+      -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, "negative 1 year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2031-07-16", "2021-07-16", opt),
+      -10, 0, 0, 0, 0, 0, 0, 0, 0, 0, "negative 10 years");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2022-07-19", "2021-07-16", opt),
+      -1, 0, 0, -3, 0, 0, 0, 0, 0, 0, "negative 1 year and 3 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2022-09-19", "2021-07-16", opt),
+      -1, -2, 0, -3, 0, 0, 0, 0, 0, 0, "negative 1 year 2 months and 3 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2031-12-16", "2021-07-16", opt),
+      -10, -5, 0, 0, 0, 0, 0, 0, 0, 0, "negative 10 years and 5 months");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "1997-12-16", opt),
+      -23, -7, 0, 0, 0, 0, 0, 0, 0, 0, "negative 23 years and 7 months");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "1997-07-16", opt),
+      -24, 0, 0, 0, 0, 0, 0, 0, 0, 0, "negative 24 years");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-15", "1997-07-16", opt),
+      -23, -11, 0, -30, 0, 0, 0, 0, 0, 0, "negative 23 years, 11 months and 30 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-06-15", "1997-06-16", opt),
+      -23, -11, 0, -29, 0, 0, 0, 0, 0, 0, "negative 23 years, 11 months and 29 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2020-03-16", "1960-02-16", opt),
+      -60, -1, 0, 0, 0, 0, 0, 0, 0, 0, "negative 60 years, 1 month");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-03-15", "1960-02-16", opt),
+      -61, 0, 0, -28, 0, 0, 0, 0, 0, 0, "negative 61 years, 28 days in non leap year");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2020-03-15", "1960-02-16", opt),
+      -60, 0, 0, -28, 0, 0, 0, 0, 0, 0, "negative 60 years, 28 days in leap year");
 
-  assert.sameValue("-P10Y5M",
-      cal.dateUntil("2031-12-16", "2021-07-16", opt).toJSON());
-  assert.sameValue("-P13Y7M",
-      cal.dateUntil("2011-07-16", "1997-12-16", opt).toJSON());
-  assert.sameValue("-P24Y",
-      cal.dateUntil("2021-07-16", "1997-07-16", opt).toJSON());
-  assert.sameValue("-P23Y11M30D",
-      cal.dateUntil("2021-07-15", "1997-07-16", opt).toJSON());
-  assert.sameValue("-P23Y11M29D",
-      cal.dateUntil("2021-06-15", "1997-06-16", opt).toJSON());
-  assert.sameValue("-P60Y1M",
-      cal.dateUntil("2020-03-16", "1960-02-16", opt).toJSON());
-  assert.sameValue("-P61Y28D",
-      cal.dateUntil("2021-03-15", "1960-02-16", opt).toJSON());
-  assert.sameValue("-P60Y28D",
-      cal.dateUntil("2020-03-15", "1960-02-16", opt).toJSON());
-
-  assert.sameValue("-P61Y3M17D",
-      cal.dateUntil("2021-07-16", "1960-03-30", opt).toJSON());
-
-  assert.sameValue("-P2019Y6M22D",
-      cal.dateUntil("2021-07-16", "0001-12-25", opt).toJSON());
-  assert.sameValue("-P23Y6M17D",
-      cal.dateUntil("2021-07-16", "1997-12-30", opt).toJSON());
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-03-30", opt),
+      0, -3, 0, -17, 0, 0, 0, 0, 0, 0, "negative 3 months and 17 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2020-03-30", opt),
+      -1, -3, 0, -17, 0, 0, 0, 0, 0, 0, "negative 1 year, 3 months and 17 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "1960-03-30", opt),
+      -61, -3, 0, -17, 0, 0, 0, 0, 0, 0, "negative 61 years, 3 months and 17 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2019-12-30", opt),
+      -1, -6, 0, -17, 0, 0, 0, 0, 0, 0, "negative 1 year, 6 months and 17 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2020-12-30", opt),
+      0, -6, 0, -17, 0, 0, 0, 0, 0, 0, "negative 6 months and 17 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "1997-12-30", opt),
+      -23, -6, 0, -17, 0, 0, 0, 0, 0, 0, "negative 23 years, 6 months and 17 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "0001-12-25", opt),
+      -2019, -6, 0, -22, 0, 0, 0, 0, 0, 0, "negative 2019 years, 6 months and 22 days");
+  TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-03-05", "2019-12-30", opt),
+      -1, -2, 0, -6, 0, 0, 0, 0, 0, 0, "negative 1 year, 2 months and 6 days");
 });
diff --git a/test/built-ins/Temporal/Calendar/prototype/dateUntil/no-options.js b/test/built-ins/Temporal/Calendar/prototype/dateUntil/no-options.js
index e0eea3ecf8..962400e354 100644
--- a/test/built-ins/Temporal/Calendar/prototype/dateUntil/no-options.js
+++ b/test/built-ins/Temporal/Calendar/prototype/dateUntil/no-options.js
@@ -3,7 +3,7 @@
 
 /*---
 esid: sec-temporal.calendar.prototype.dateuntil
-description: Temporal.Calendar.prototype.dateUntil w/o options
+description: Temporal.Calendar.prototype.dateUntil with no options
 info: |
   1. Let calendar be the this value.
   2. Perform ? RequireInternalSlot(calendar, [[InitializedTemporalCalendar]]).
@@ -15,18 +15,42 @@ info: |
   8. Let result be ! DifferenceISODate(one.[[ISOYear]], one.[[ISOMonth]], one.[[ISODay]], two.[[ISOYear]], two.[[ISOMonth]], two.[[ISODay]], largestUnit).
   9. Return ? CreateTemporalDuration(result.[[Years]], result.[[Months]], result.[[Weeks]], result.[[Days]], 0, 0, 0, 0, 0, 0).
 features: [Temporal]
+includes: [temporalHelpers.js]
 ---*/
 let cal = new Temporal.Calendar("iso8601");
 
-assert.sameValue("PT0S", cal.dateUntil("2021-07-16", "2021-07-16").toJSON());
-assert.sameValue("P1D", cal.dateUntil("2021-07-16", "2021-07-17").toJSON());
-assert.sameValue("P32D", cal.dateUntil("2021-07-16", "2021-08-17").toJSON());
-assert.sameValue("P62D", cal.dateUntil("2021-07-16", "2021-09-16").toJSON());
-assert.sameValue("P365D", cal.dateUntil("2021-07-16", "2022-07-16").toJSON());
-assert.sameValue("P3652D", cal.dateUntil("2021-07-16", "2031-07-16").toJSON());
+TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-16"),
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, "same day");
+TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-07-17"),
+      0, 0, 0, 1, 0, 0, 0, 0, 0, 0, "one day");
+TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-08-17"),
+      0, 0, 0, 32, 0, 0, 0, 0, 0, 0, "32 days");
+TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2021-09-16"),
+      0, 0, 0, 62, 0, 0, 0, 0, 0, 0, "62 days");
+TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2022-07-16"),
+      0, 0, 0, 365, 0, 0, 0, 0, 0, 0, "365 days");
+TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-16", "2031-07-16"),
+      0, 0, 0, 3652, 0, 0, 0, 0, 0, 0, "3652 days");
 
-assert.sameValue("-P1D", cal.dateUntil("2021-07-17", "2021-07-16").toJSON());
-assert.sameValue("-P32D", cal.dateUntil("2021-08-17", "2021-07-16").toJSON());
-assert.sameValue("-P62D", cal.dateUntil("2021-09-16", "2021-07-16").toJSON());
-assert.sameValue("-P365D", cal.dateUntil("2022-07-16", "2021-07-16").toJSON());
-assert.sameValue("-P3652D", cal.dateUntil("2031-07-16", "2021-07-16").toJSON());
+
+TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-07-17", "2021-07-16"),
+      0, 0, 0, -1, 0, 0, 0, 0, 0, 0, "negative one day");
+TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-08-17", "2021-07-16"),
+      0, 0, 0, -32, 0, 0, 0, 0, 0, 0, "negative 32 days");
+TemporalHelpers.assertDuration(
+      cal.dateUntil("2021-09-16", "2021-07-16"),
+      0, 0, 0, -62, 0, 0, 0, 0, 0, 0, "negative 62 days");
+TemporalHelpers.assertDuration(
+      cal.dateUntil("2022-07-16", "2021-07-16"),
+      0, 0, 0, -365, 0, 0, 0, 0, 0, 0, "negative 365 days");
+TemporalHelpers.assertDuration(
+      cal.dateUntil("2031-07-16", "2021-07-16"),
+      0, 0, 0, -3652, 0, 0, 0, 0, 0, 0, "negative 3652 days");
diff --git a/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-range-error-ToLargestTemporalUnit.js b/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-range-error-ToLargestTemporalUnit.js
new file mode 100644
index 0000000000..6f5ddc7b99
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-range-error-ToLargestTemporalUnit.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.dateuntil
+description: Temporal.Calendar.prototype.dateUntil throw RangeError on ToLargestTemporalUnit with invalide or disallowed unit
+info: |
+  7. Let largestUnit be ? ToLargestTemporalUnit(options, « "hour", "minute", "second", "millisecond", "microsecond", "nanosecond" », "auto", "day").
+features: [Temporal]
+---*/
+let cal = new Temporal.Calendar("iso8601");
+
+["invalid", "hour", "minute", "second", "millisecond", "microsecond",
+    "nanosecond"].forEach(function(largestUnit) {
+  assert.throws(RangeError, () => cal.dateUntil("2021-07-16", "2022-03-04", {largestUnit}),
+      "Invalid or disallowed largestUnit cause ToLargestTemporalUnit to throw RangeError");
+})
diff --git a/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-range-error-ToTemporalDate.js b/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-range-error-ToTemporalDate.js
new file mode 100644
index 0000000000..dc0c3ed57c
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-range-error-ToTemporalDate.js
@@ -0,0 +1,18 @@
+// Copyright (C) 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.dateuntil
+description: Temporal.Calendar.prototype.dateUntil throw RangeError on ToTemporalDate
+info: |
+  1. Let calendar be the this value.
+  4. Set one to ? ToTemporalDate(one).
+  5. Set two to ? ToTemporalDate(two).
+features: [Temporal]
+---*/
+let cal = new Temporal.Calendar("iso8601");
+
+assert.throws(RangeError, () => cal.dateUntil("2021-07-16", "invalide date"),
+      "Invalid date string will cause ToTemporalDate to throw RangeError");
+assert.throws(RangeError, () => cal.dateUntil("invalide date", "2021-07-16"),
+      "Invalid date string will cause ToTemporalDate to throw RangeError");
diff --git a/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-type-error-GetOptionsObject.js b/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-type-error-GetOptionsObject.js
new file mode 100644
index 0000000000..2aca08890b
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-type-error-GetOptionsObject.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.dateuntil
+description: Temporal.Calendar.prototype.dateUntil throw TypeError on GetOptionsObject
+info: |
+  6. Set options to ? GetOptionsObject(options).
+features: [Temporal]
+---*/
+let cal = new Temporal.Calendar("iso8601");
+
+["string", null, true, false, 123, 456n, Symbol(), Infinity, NaN].forEach(function (opt) {
+  assert.throws(TypeError, () => cal.dateUntil("2021-07-16", "2021-08-11", opt),
+      "Invalid options will cause GetOptionsObject to throw TypeError");
+})
diff --git a/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-type-error-RequireInternalSlot.js b/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-type-error-RequireInternalSlot.js
new file mode 100644
index 0000000000..b4deb5b3de
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/dateUntil/throws-type-error-RequireInternalSlot.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.dateuntil
+description: Temporal.Calendar.prototype.dateUntil throw TypeError on RequireInternalSlot
+info: |
+  1. Let calendar be the this value.
+  2. Perform ? RequireInternalSlot(calendar, [[InitializedTemporalCalendar]]).
+features: [Temporal]
+---*/
+let cal = new Temporal.Calendar("iso8601");
+let badCal = { dateUntil: cal.dateUntil };
+
+assert.throws(TypeError, () => badCal.dateUntil("2021-07-16", "2021-07-17"),
+      "call dateUntil from object without internal slot should throw TypeError");