diff --git a/test/built-ins/Temporal/PlainTime/from/argument-number.js b/test/built-ins/Temporal/PlainTime/from/argument-number.js
new file mode 100644
index 0000000000..6f215a4e4a
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/from/argument-number.js
@@ -0,0 +1,12 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.from
+description: Number argument is converted to string
+includes: [compareArray.js, temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const result = Temporal.PlainTime.from(1523);
+TemporalHelpers.assertPlainTime(result, 15, 23, 0, 0, 0, 0);
diff --git a/test/built-ins/Temporal/PlainTime/from/argument-object-leap-second.js b/test/built-ins/Temporal/PlainTime/from/argument-object-leap-second.js
new file mode 100644
index 0000000000..de580b2331
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/from/argument-object-leap-second.js
@@ -0,0 +1,23 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.from
+description: Object argument handles leap seconds according to the overflow option.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+for (const options of [undefined, {}, { overflow: "constrain" }]) {
+  TemporalHelpers.assertPlainTime(Temporal.PlainTime.from({ hour: 23, minute: 59, second: 60 }, options),
+    23, 59, 59, 0, 0, 0);
+  TemporalHelpers.assertPlainTime(Temporal.PlainTime.from({ hour: 12, minute: 30, second: 60 }, options),
+    12, 30, 59, 0, 0, 0);
+  TemporalHelpers.assertPlainTime(Temporal.PlainTime.from({ hour: 23, minute: 59, second: 60, millisecond: 170 }, options),
+    23, 59, 59, 170, 0, 0);
+}
+
+const options = { overflow: "reject" };
+assert.throws(RangeError, () => Temporal.PlainTime.from({ hour: 23, minute: 59, second: 60 }, options));
+assert.throws(RangeError, () => Temporal.PlainTime.from({ hour: 12, minute: 30, second: 60 }, options));
+assert.throws(RangeError, () => Temporal.PlainTime.from({ hour: 23, minute: 59, second: 60, millisecond: 170 }, options));
diff --git a/test/built-ins/Temporal/PlainTime/from/argument-object.js b/test/built-ins/Temporal/PlainTime/from/argument-object.js
new file mode 100644
index 0000000000..59a69c8806
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/from/argument-object.js
@@ -0,0 +1,21 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.from
+description: Plain object argument is supported and ignores plural properties
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from({ hour: 15, minute: 23 }),
+  15, 23, 0, 0, 0, 0);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from({ minute: 30, microsecond: 555 }),
+  0, 30, 0, 0, 555, 0);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from({ year: 2019, month: 10, day: 1, hour: 14, minute: 20, second: 36 }),
+  14, 20, 36, 0, 0, 0);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from({ hours: 2, minute: 30, microsecond: 555 }),
+  0, 30, 0, 0, 555, 0);
+
+assert.throws(TypeError, () => Temporal.PlainTime.from({}));
+assert.throws(TypeError, () => Temporal.PlainTime.from({ minutes: 12 }));
diff --git a/test/built-ins/Temporal/PlainTime/from/argument-string-leap-second.js b/test/built-ins/Temporal/PlainTime/from/argument-string-leap-second.js
new file mode 100644
index 0000000000..cb960920ee
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/from/argument-string-leap-second.js
@@ -0,0 +1,18 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.from
+description: Leap second is replaced by :59 in ISO strings.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+for (const options of [undefined, {}, { overflow: "constrain" }, { overflow: "reject" }]) {
+  TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("23:59:60", options),
+    23, 59, 59, 0, 0, 0);
+  TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("12:30:60", options),
+    12, 30, 59, 0, 0, 0);
+  TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("23:59:60.170", options),
+    23, 59, 59, 170, 0, 0);
+}
diff --git a/test/built-ins/Temporal/PlainTime/from/overflow-constrain.js b/test/built-ins/Temporal/PlainTime/from/overflow-constrain.js
new file mode 100644
index 0000000000..9048d1b7a0
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/from/overflow-constrain.js
@@ -0,0 +1,14 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.from
+description: constrain value for overflow option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from({ hour: 26 }, { overflow: "constrain" }),
+  23, 0, 0, 0, 0, 0);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from({ hour: 22 }, { overflow: "constrain" }),
+  22, 0, 0, 0, 0, 0);
diff --git a/test/built-ins/Temporal/PlainTime/from/overflow-reject.js b/test/built-ins/Temporal/PlainTime/from/overflow-reject.js
new file mode 100644
index 0000000000..7f76deab50
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/from/overflow-reject.js
@@ -0,0 +1,13 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.from
+description: reject value for overflow option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+assert.throws(RangeError, () => Temporal.PlainTime.from({ hour: 26 }, { overflow: "reject" }));
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from({ hour: 22 }, { overflow: "reject" }),
+  22, 0, 0, 0, 0, 0);
diff --git a/test/built-ins/Temporal/PlainTime/negative-zero.js b/test/built-ins/Temporal/PlainTime/negative-zero.js
new file mode 100644
index 0000000000..4959e4323d
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/negative-zero.js
@@ -0,0 +1,12 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime
+description: Negative zero arguments are treated as zero.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(-0, -0, -0, -0, -0, -0);
+TemporalHelpers.assertPlainTime(plainTime, 0, 0, 0, 0, 0, 0);
diff --git a/test/built-ins/Temporal/PlainTime/prototype/add/argument-duration.js b/test/built-ins/Temporal/PlainTime/prototype/add/argument-duration.js
new file mode 100644
index 0000000000..0a4e1070f3
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/add/argument-duration.js
@@ -0,0 +1,14 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.add
+description: Duration arguments are supported.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(15, 23, 30, 123, 456, 789);
+const duration = Temporal.Duration.from("PT16H");
+TemporalHelpers.assertPlainTime(plainTime.add(duration),
+  7, 23, 30, 123, 456, 789);
diff --git a/test/built-ins/Temporal/PlainTime/prototype/add/argument-higher-units.js b/test/built-ins/Temporal/PlainTime/prototype/add/argument-higher-units.js
new file mode 100644
index 0000000000..af4913e217
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/add/argument-higher-units.js
@@ -0,0 +1,29 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.add
+description: Higher units are ignored.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(15, 23, 30, 123, 456, 789);
+const values = [
+  new Temporal.Duration(0, 0, 0, 1),
+  new Temporal.Duration(0, 0, 1),
+  new Temporal.Duration(0, 1),
+  new Temporal.Duration(1),
+  { days: 1 },
+  { weeks: 1 },
+  { months: 1 },
+  { years: 1 },
+  "P1D",
+  "P1W",
+  "P1M",
+  "P1Y",
+];
+for (const value of values) {
+  TemporalHelpers.assertPlainTime(plainTime.add(value),
+    15, 23, 30, 123, 456, 789);
+}
diff --git a/test/built-ins/Temporal/PlainTime/prototype/add/argument-object.js b/test/built-ins/Temporal/PlainTime/prototype/add/argument-object.js
new file mode 100644
index 0000000000..4f0bdaa2b5
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/add/argument-object.js
@@ -0,0 +1,37 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.add
+description: Plain object arguments are supported.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.add({ hours: 16 }),
+  7, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.add({ minutes: 45 }),
+  16, 8, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.add({ seconds: 800 }),
+  15, 36, 50, 123, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.add({ milliseconds: 800 }),
+  15, 23, 30, 923, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.add({ microseconds: 800 }),
+  15, 23, 30, 124, 256, 789);
+TemporalHelpers.assertPlainTime(plainTime.add({ nanoseconds: 300 }),
+  15, 23, 30, 123, 457, 89);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("07:23:30.123456789").add({ hours: -16 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("16:08:30.123456789").add({ minutes: -45 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("15:36:50.123456789").add({ seconds: -800 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("15:23:30.923456789").add({ milliseconds: -800 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("15:23:30.124256789").add({ microseconds: -800 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("15:23:30.123457089").add({ nanoseconds: -300 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.add({ minute: 1, hours: 1 }),
+  16, 23, 30, 123, 456, 789);
diff --git a/test/built-ins/Temporal/PlainTime/prototype/round/rounding-cross-midnight.js b/test/built-ins/Temporal/PlainTime/prototype/round/rounding-cross-midnight.js
new file mode 100644
index 0000000000..9b28178314
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/round/rounding-cross-midnight.js
@@ -0,0 +1,14 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.round
+description: Rounding can cross midnight
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = Temporal.PlainTime.from("23:59:59.999999999");
+for (const smallestUnit of ["hour", "minute", "second", "millisecond", "microsecond"]) {
+  TemporalHelpers.assertPlainTime(plainTime.round({ smallestUnit }), 0, 0, 0, 0, 0, 0);
+}
diff --git a/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-hours.js b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-hours.js
new file mode 100644
index 0000000000..666fd223d0
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-hours.js
@@ -0,0 +1,33 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.round
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(3, 34, 56, 987, 654, 321);
+
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "hours", roundingIncrement: 1 }),
+  4, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "hours", roundingIncrement: 2 }),
+  4, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "hours", roundingIncrement: 3 }),
+  3, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "hours", roundingIncrement: 4 }),
+  4, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "hours", roundingIncrement: 6 }),
+  6, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "hours", roundingIncrement: 8 }),
+  0, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "hours", roundingIncrement: 12 }),
+  0, 0, 0, 0, 0, 0, "hours");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-microseconds.js b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-microseconds.js
new file mode 100644
index 0000000000..6eb685312a
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-microseconds.js
@@ -0,0 +1,57 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.round
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(3, 34, 56, 987, 654, 321);
+
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 1 }),
+  3, 34, 56, 987, 654, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 2 }),
+  3, 34, 56, 987, 654, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 4 }),
+  3, 34, 56, 987, 656, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 5 }),
+  3, 34, 56, 987, 655, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 8 }),
+  3, 34, 56, 987, 656, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 10 }),
+  3, 34, 56, 987, 650, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 20 }),
+  3, 34, 56, 987, 660, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 25 }),
+  3, 34, 56, 987, 650, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 40 }),
+  3, 34, 56, 987, 640, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 50 }),
+  3, 34, 56, 987, 650, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 100 }),
+  3, 34, 56, 987, 700, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 125 }),
+  3, 34, 56, 987, 625, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 200 }),
+  3, 34, 56, 987, 600, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 250 }),
+  3, 34, 56, 987, 750, 0, "microseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "microseconds", roundingIncrement: 500 }),
+  3, 34, 56, 987, 500, 0, "microseconds");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-milliseconds.js b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-milliseconds.js
new file mode 100644
index 0000000000..a33615f4d1
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-milliseconds.js
@@ -0,0 +1,57 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.round
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(3, 34, 56, 987, 654, 321);
+
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 1 }),
+  3, 34, 56, 988, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 2 }),
+  3, 34, 56, 988, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 4 }),
+  3, 34, 56, 988, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 5 }),
+  3, 34, 56, 990, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 8 }),
+  3, 34, 56, 984, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 10 }),
+  3, 34, 56, 990, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 20 }),
+  3, 34, 56, 980, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 25 }),
+  3, 34, 57, 0, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 40 }),
+  3, 34, 57, 0, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 50 }),
+  3, 34, 57, 0, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 100 }),
+  3, 34, 57, 0, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 125 }),
+  3, 34, 57, 0, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 200 }),
+  3, 34, 57, 0, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 250 }),
+  3, 34, 57, 0, 0, 0, "milliseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "milliseconds", roundingIncrement: 500 }),
+  3, 34, 57, 0, 0, 0, "milliseconds");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-minutes.js b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-minutes.js
new file mode 100644
index 0000000000..297407eb17
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-minutes.js
@@ -0,0 +1,45 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.round
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(3, 34, 56, 987, 654, 321);
+
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "minutes", roundingIncrement: 1 }),
+  3, 35, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "minutes", roundingIncrement: 2 }),
+  3, 34, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "minutes", roundingIncrement: 3 }),
+  3, 36, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "minutes", roundingIncrement: 4 }),
+  3, 36, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "minutes", roundingIncrement: 5 }),
+  3, 35, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "minutes", roundingIncrement: 6 }),
+  3, 36, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "minutes", roundingIncrement: 10 }),
+  3, 30, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "minutes", roundingIncrement: 12 }),
+  3, 36, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "minutes", roundingIncrement: 15 }),
+  3, 30, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "minutes", roundingIncrement: 20 }),
+  3, 40, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "minutes", roundingIncrement: 30 }),
+  3, 30, 0, 0, 0, 0, "minutes");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-nanoseconds.js b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-nanoseconds.js
new file mode 100644
index 0000000000..0992ce73a2
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-nanoseconds.js
@@ -0,0 +1,57 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.round
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(3, 34, 56, 987, 654, 321);
+
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 1 }),
+  3, 34, 56, 987, 654, 321, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 2 }),
+  3, 34, 56, 987, 654, 322, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 4 }),
+  3, 34, 56, 987, 654, 320, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 5 }),
+  3, 34, 56, 987, 654, 320, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 8 }),
+  3, 34, 56, 987, 654, 320, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 10 }),
+  3, 34, 56, 987, 654, 320, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 20 }),
+  3, 34, 56, 987, 654, 320, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 25 }),
+  3, 34, 56, 987, 654, 325, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 40 }),
+  3, 34, 56, 987, 654, 320, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 50 }),
+  3, 34, 56, 987, 654, 300, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 100 }),
+  3, 34, 56, 987, 654, 300, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 125 }),
+  3, 34, 56, 987, 654, 375, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 200 }),
+  3, 34, 56, 987, 654, 400, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 250 }),
+  3, 34, 56, 987, 654, 250, "nanoseconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "nanoseconds", roundingIncrement: 500 }),
+  3, 34, 56, 987, 654, 500, "nanoseconds");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-seconds.js b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-seconds.js
new file mode 100644
index 0000000000..11bbb6a7a6
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/round/roundingincrement-seconds.js
@@ -0,0 +1,45 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.round
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(3, 34, 56, 987, 654, 321);
+
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "seconds", roundingIncrement: 1 }),
+  3, 34, 57, 0, 0, 0, "seconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "seconds", roundingIncrement: 2 }),
+  3, 34, 56, 0, 0, 0, "seconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "seconds", roundingIncrement: 3 }),
+  3, 34, 57, 0, 0, 0, "seconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "seconds", roundingIncrement: 4 }),
+  3, 34, 56, 0, 0, 0, "seconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "seconds", roundingIncrement: 5 }),
+  3, 34, 55, 0, 0, 0, "seconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "seconds", roundingIncrement: 6 }),
+  3, 34, 54, 0, 0, 0, "seconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "seconds", roundingIncrement: 10 }),
+  3, 35, 0, 0, 0, 0, "seconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "seconds", roundingIncrement: 12 }),
+  3, 35, 0, 0, 0, 0, "seconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "seconds", roundingIncrement: 15 }),
+  3, 35, 0, 0, 0, 0, "seconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "seconds", roundingIncrement: 20 }),
+  3, 35, 0, 0, 0, 0, "seconds");
+TemporalHelpers.assertPlainTime(
+  plainTime.round({ smallestUnit: "seconds", roundingIncrement: 30 }),
+  3, 35, 0, 0, 0, 0, "seconds");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-hours.js b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-hours.js
new file mode 100644
index 0000000000..dc57609720
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-hours.js
@@ -0,0 +1,34 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.since
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "hours", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "hours", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "hours", roundingIncrement: 3 }),
+  0, 0, 0, 0, 9, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "hours", roundingIncrement: 4 }),
+  0, 0, 0, 0, 8, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "hours", roundingIncrement: 6 }),
+  0, 0, 0, 0, 6, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "hours", roundingIncrement: 8 }),
+  0, 0, 0, 0, 8, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "hours", roundingIncrement: 12 }),
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, "hours");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-microseconds.js b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-microseconds.js
new file mode 100644
index 0000000000..ded0e0d908
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-microseconds.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.since
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 4 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 196, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 5 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 195, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 8 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 192, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 10 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 190, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 20 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 180, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 25 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 175, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 40 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 160, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 50 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 150, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 100 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 100, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 125 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 125, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 200 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 0, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 250 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 0, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "microseconds", roundingIncrement: 500 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 0, 0, "microseconds");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-milliseconds.js b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-milliseconds.js
new file mode 100644
index 0000000000..4a6c867dde
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-milliseconds.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.since
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 35, 23, 864, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 4 }),
+  0, 0, 0, 0, 10, 35, 23, 864, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 5 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 8 }),
+  0, 0, 0, 0, 10, 35, 23, 864, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 10 }),
+  0, 0, 0, 0, 10, 35, 23, 860, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 20 }),
+  0, 0, 0, 0, 10, 35, 23, 860, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 25 }),
+  0, 0, 0, 0, 10, 35, 23, 850, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 40 }),
+  0, 0, 0, 0, 10, 35, 23, 840, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 50 }),
+  0, 0, 0, 0, 10, 35, 23, 850, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 100 }),
+  0, 0, 0, 0, 10, 35, 23, 800, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 125 }),
+  0, 0, 0, 0, 10, 35, 23, 750, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 200 }),
+  0, 0, 0, 0, 10, 35, 23, 800, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 250 }),
+  0, 0, 0, 0, 10, 35, 23, 750, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "milliseconds", roundingIncrement: 500 }),
+  0, 0, 0, 0, 10, 35, 23, 500, 0, 0, "milliseconds");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-minutes.js b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-minutes.js
new file mode 100644
index 0000000000..05a62d4269
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-minutes.js
@@ -0,0 +1,46 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.since
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "minutes", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 35, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "minutes", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 34, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "minutes", roundingIncrement: 3 }),
+  0, 0, 0, 0, 10, 33, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "minutes", roundingIncrement: 4 }),
+  0, 0, 0, 0, 10, 32, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "minutes", roundingIncrement: 5 }),
+  0, 0, 0, 0, 10, 35, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "minutes", roundingIncrement: 6 }),
+  0, 0, 0, 0, 10, 30, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "minutes", roundingIncrement: 10 }),
+  0, 0, 0, 0, 10, 30, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "minutes", roundingIncrement: 12 }),
+  0, 0, 0, 0, 10, 24, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "minutes", roundingIncrement: 15 }),
+  0, 0, 0, 0, 10, 30, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "minutes", roundingIncrement: 20 }),
+  0, 0, 0, 0, 10, 20, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "minutes", roundingIncrement: 30 }),
+  0, 0, 0, 0, 10, 30, 0, 0, 0, 0, "minutes");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-nanoseconds.js b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-nanoseconds.js
new file mode 100644
index 0000000000..cc43a8e3e9
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-nanoseconds.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.since
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 533, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 532, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 4 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 532, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 5 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 530, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 8 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 528, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 10 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 530, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 20 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 520, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 25 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 525, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 40 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 520, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 50 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 500, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 100 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 500, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 125 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 500, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 200 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 400, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 250 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 500, "nanoseconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "nanoseconds", roundingIncrement: 500 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 500, "nanoseconds");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-seconds.js b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-seconds.js
new file mode 100644
index 0000000000..ac24ee8ce8
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/since/roundingincrement-seconds.js
@@ -0,0 +1,46 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.since
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "seconds", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 35, 23, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "seconds", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 35, 22, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "seconds", roundingIncrement: 3 }),
+  0, 0, 0, 0, 10, 35, 21, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "seconds", roundingIncrement: 4 }),
+  0, 0, 0, 0, 10, 35, 20, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "seconds", roundingIncrement: 5 }),
+  0, 0, 0, 0, 10, 35, 20, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "seconds", roundingIncrement: 6 }),
+  0, 0, 0, 0, 10, 35, 18, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "seconds", roundingIncrement: 10 }),
+  0, 0, 0, 0, 10, 35, 20, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "seconds", roundingIncrement: 12 }),
+  0, 0, 0, 0, 10, 35, 12, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "seconds", roundingIncrement: 15 }),
+  0, 0, 0, 0, 10, 35, 15, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "seconds", roundingIncrement: 20 }),
+  0, 0, 0, 0, 10, 35, 20, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  later.since(earlier, { smallestUnit: "seconds", roundingIncrement: 30 }),
+  0, 0, 0, 0, 10, 35, 0, 0, 0, 0, "seconds");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/subtract/argument-duration.js b/test/built-ins/Temporal/PlainTime/prototype/subtract/argument-duration.js
new file mode 100644
index 0000000000..eff64119bc
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/subtract/argument-duration.js
@@ -0,0 +1,14 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.subtract
+description: Duration arguments are supported.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(15, 23, 30, 123, 456, 789);
+const duration = Temporal.Duration.from("PT16H");
+TemporalHelpers.assertPlainTime(plainTime.subtract(duration),
+  23, 23, 30, 123, 456, 789);
diff --git a/test/built-ins/Temporal/PlainTime/prototype/subtract/argument-higher-units.js b/test/built-ins/Temporal/PlainTime/prototype/subtract/argument-higher-units.js
new file mode 100644
index 0000000000..8e64720573
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/subtract/argument-higher-units.js
@@ -0,0 +1,29 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.subtract
+description: Higher units are ignored.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(15, 23, 30, 123, 456, 789);
+const values = [
+  new Temporal.Duration(0, 0, 0, 1),
+  new Temporal.Duration(0, 0, 1),
+  new Temporal.Duration(0, 1),
+  new Temporal.Duration(1),
+  { days: 1 },
+  { weeks: 1 },
+  { months: 1 },
+  { years: 1 },
+  "P1D",
+  "P1W",
+  "P1M",
+  "P1Y",
+];
+for (const value of values) {
+  TemporalHelpers.assertPlainTime(plainTime.subtract(value),
+    15, 23, 30, 123, 456, 789);
+}
diff --git a/test/built-ins/Temporal/PlainTime/prototype/subtract/argument-object.js b/test/built-ins/Temporal/PlainTime/prototype/subtract/argument-object.js
new file mode 100644
index 0000000000..a981492bdf
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/subtract/argument-object.js
@@ -0,0 +1,37 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.subtract
+description: Plain object arguments are supported.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const plainTime = new Temporal.PlainTime(15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.subtract({ hours: 16 }),
+  23, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.subtract({ minutes: 45 }),
+  14, 38, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.subtract({ seconds: 45 }),
+  15, 22, 45, 123, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.subtract({ milliseconds: 800 }),
+  15, 23, 29, 323, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.subtract({ microseconds: 800 }),
+  15, 23, 30, 122, 656, 789);
+TemporalHelpers.assertPlainTime(plainTime.subtract({ nanoseconds: 800 }),
+  15, 23, 30, 123, 455, 989);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("23:23:30.123456789").subtract({ hours: -16 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("14:38:30.123456789").subtract({ minutes: -45 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("15:22:45.123456789").subtract({ seconds: -45 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("15:23:29.323456789").subtract({ milliseconds: -800 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("15:23:30.122656789").subtract({ microseconds: -800 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(Temporal.PlainTime.from("15:23:30.123455989").subtract({ nanoseconds: -800 }),
+  15, 23, 30, 123, 456, 789);
+TemporalHelpers.assertPlainTime(plainTime.subtract({ minute: 1, hours: 1 }),
+  14, 23, 30, 123, 456, 789);
diff --git a/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-hours.js b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-hours.js
new file mode 100644
index 0000000000..9245498b40
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-hours.js
@@ -0,0 +1,34 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.until
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "hours", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "hours", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "hours", roundingIncrement: 3 }),
+  0, 0, 0, 0, 9, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "hours", roundingIncrement: 4 }),
+  0, 0, 0, 0, 8, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "hours", roundingIncrement: 6 }),
+  0, 0, 0, 0, 6, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "hours", roundingIncrement: 8 }),
+  0, 0, 0, 0, 8, 0, 0, 0, 0, 0, "hours");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "hours", roundingIncrement: 12 }),
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, "hours");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-microseconds.js b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-microseconds.js
new file mode 100644
index 0000000000..2bde9cd4af
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-microseconds.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.until
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 4 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 196, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 5 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 195, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 8 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 192, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 10 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 190, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 20 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 180, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 25 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 175, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 40 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 160, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 50 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 150, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 100 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 100, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 125 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 125, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 200 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 0, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 250 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 0, 0, "microseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "microseconds", roundingIncrement: 500 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 0, 0, "microseconds");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-milliseconds.js b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-milliseconds.js
new file mode 100644
index 0000000000..2eade031db
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-milliseconds.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.until
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 35, 23, 864, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 4 }),
+  0, 0, 0, 0, 10, 35, 23, 864, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 5 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 8 }),
+  0, 0, 0, 0, 10, 35, 23, 864, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 10 }),
+  0, 0, 0, 0, 10, 35, 23, 860, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 20 }),
+  0, 0, 0, 0, 10, 35, 23, 860, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 25 }),
+  0, 0, 0, 0, 10, 35, 23, 850, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 40 }),
+  0, 0, 0, 0, 10, 35, 23, 840, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 50 }),
+  0, 0, 0, 0, 10, 35, 23, 850, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 100 }),
+  0, 0, 0, 0, 10, 35, 23, 800, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 125 }),
+  0, 0, 0, 0, 10, 35, 23, 750, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 200 }),
+  0, 0, 0, 0, 10, 35, 23, 800, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 250 }),
+  0, 0, 0, 0, 10, 35, 23, 750, 0, 0, "milliseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "milliseconds", roundingIncrement: 500 }),
+  0, 0, 0, 0, 10, 35, 23, 500, 0, 0, "milliseconds");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-minutes.js b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-minutes.js
new file mode 100644
index 0000000000..371d8fcb83
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-minutes.js
@@ -0,0 +1,46 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.until
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "minutes", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 35, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "minutes", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 34, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "minutes", roundingIncrement: 3 }),
+  0, 0, 0, 0, 10, 33, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "minutes", roundingIncrement: 4 }),
+  0, 0, 0, 0, 10, 32, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "minutes", roundingIncrement: 5 }),
+  0, 0, 0, 0, 10, 35, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "minutes", roundingIncrement: 6 }),
+  0, 0, 0, 0, 10, 30, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "minutes", roundingIncrement: 10 }),
+  0, 0, 0, 0, 10, 30, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "minutes", roundingIncrement: 12 }),
+  0, 0, 0, 0, 10, 24, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "minutes", roundingIncrement: 15 }),
+  0, 0, 0, 0, 10, 30, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "minutes", roundingIncrement: 20 }),
+  0, 0, 0, 0, 10, 20, 0, 0, 0, 0, "minutes");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "minutes", roundingIncrement: 30 }),
+  0, 0, 0, 0, 10, 30, 0, 0, 0, 0, "minutes");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-nanoseconds.js b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-nanoseconds.js
new file mode 100644
index 0000000000..7ec306ff7a
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-nanoseconds.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.until
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 533, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 532, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 4 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 532, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 5 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 530, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 8 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 528, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 10 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 530, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 20 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 520, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 25 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 525, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 40 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 520, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 50 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 500, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 100 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 500, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 125 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 500, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 200 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 400, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 250 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 500, "nanoseconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "nanoseconds", roundingIncrement: 500 }),
+  0, 0, 0, 0, 10, 35, 23, 865, 198, 500, "nanoseconds");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-seconds.js b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-seconds.js
new file mode 100644
index 0000000000..eb5edd775a
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/until/roundingincrement-seconds.js
@@ -0,0 +1,46 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.until
+description: Valid values for roundingIncrement option
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const earlier = new Temporal.PlainTime(3, 12, 34, 123, 456, 789);
+const later = new Temporal.PlainTime(13, 47, 57, 988, 655, 322);
+
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "seconds", roundingIncrement: 1 }),
+  0, 0, 0, 0, 10, 35, 23, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "seconds", roundingIncrement: 2 }),
+  0, 0, 0, 0, 10, 35, 22, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "seconds", roundingIncrement: 3 }),
+  0, 0, 0, 0, 10, 35, 21, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "seconds", roundingIncrement: 4 }),
+  0, 0, 0, 0, 10, 35, 20, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "seconds", roundingIncrement: 5 }),
+  0, 0, 0, 0, 10, 35, 20, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "seconds", roundingIncrement: 6 }),
+  0, 0, 0, 0, 10, 35, 18, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "seconds", roundingIncrement: 10 }),
+  0, 0, 0, 0, 10, 35, 20, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "seconds", roundingIncrement: 12 }),
+  0, 0, 0, 0, 10, 35, 12, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "seconds", roundingIncrement: 15 }),
+  0, 0, 0, 0, 10, 35, 15, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "seconds", roundingIncrement: 20 }),
+  0, 0, 0, 0, 10, 35, 20, 0, 0, 0, "seconds");
+TemporalHelpers.assertDuration(
+  earlier.until(later, { smallestUnit: "seconds", roundingIncrement: 30 }),
+  0, 0, 0, 0, 10, 35, 0, 0, 0, 0, "seconds");