diff --git a/test/built-ins/Temporal/Calendar/from/calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/from/calendar-case-insensitive.js
new file mode 100644
index 0000000000..c31020a8b7
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/from/calendar-case-insensitive.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.calendar.prototype.from
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const arg = "jApAnEsE";
+
+const result = Temporal.Calendar.from(arg);
+assert.sameValue(result.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/Calendar/prototype/dateAdd/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/dateAdd/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..a2abea1820
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/dateAdd/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// 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.calendar.prototype.dateadd
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.dateAdd(arg, new Temporal.Duration());
+TemporalHelpers.assertPlainDate(result, 1976, 11, "M11", 18, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/day/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/day/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..818bfa4b36
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/day/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.day
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.day(arg);
+assert.sameValue(result, 18, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/dayOfWeek/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/dayOfWeek/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..33aec65e06
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/dayOfWeek/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// 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.calendar.prototype.dayofweek
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.dayOfWeek(arg);
+assert.sameValue(result, 4, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/dayOfYear/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/dayOfYear/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..90d94eae52
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/dayOfYear/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.dayofyear
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.dayOfYear(arg);
+assert.sameValue(result, 323, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/daysInMonth/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/daysInMonth/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..ea94de6225
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/daysInMonth/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// 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.calendar.prototype.daysinmonth
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.daysInMonth(arg);
+assert.sameValue(result, 30, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/daysInWeek/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/daysInWeek/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..a938b2a910
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/daysInWeek/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.daysinweek
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.daysInWeek(arg);
+assert.sameValue(result, 7, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/daysInYear/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/daysInYear/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..bbee13e512
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/daysInYear/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// 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.calendar.prototype.daysinyear
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.daysInYear(arg);
+assert.sameValue(result, 366, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/inLeapYear/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/inLeapYear/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..49f8b41825
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/inLeapYear/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.inleapyear
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.inLeapYear(arg);
+assert.sameValue(result, true, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/month/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/month/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..7314b5f0b8
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/month/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// 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.calendar.prototype.month
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.month(arg);
+assert.sameValue(result, 11, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/monthCode/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/monthCode/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..6ea4441c83
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/monthCode/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.monthcode
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.monthCode(arg);
+assert.sameValue(result, "M11", `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/monthsInYear/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/monthsInYear/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..90a33288ce
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/monthsInYear/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// 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.calendar.prototype.monthsinyear
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.monthsInYear(arg);
+assert.sameValue(result, 12, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/weekOfYear/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/weekOfYear/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..0927a1a430
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/weekOfYear/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.weekofyear
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.weekOfYear(arg);
+assert.sameValue(result, 47, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Calendar/prototype/year/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/Calendar/prototype/year/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..dacab7db74
--- /dev/null
+++ b/test/built-ins/Temporal/Calendar/prototype/year/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// 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.calendar.prototype.year
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.year(arg);
+assert.sameValue(result, 1976, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/Instant/prototype/toZonedDateTime/calendar-case-insensitive.js b/test/built-ins/Temporal/Instant/prototype/toZonedDateTime/calendar-case-insensitive.js
new file mode 100644
index 0000000000..1cb96e3c66
--- /dev/null
+++ b/test/built-ins/Temporal/Instant/prototype/toZonedDateTime/calendar-case-insensitive.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.instant.prototype.tozoneddatetime
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Instant(1_000_000_000_000_000_000n);
+
+const arg = "jApAnEsE";;
+const result = instance.toZonedDateTime({ calendar: arg, timeZone: "UTC" });
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/Now/plainDate/calendar-case-insensitive.js b/test/built-ins/Temporal/Now/plainDate/calendar-case-insensitive.js
new file mode 100644
index 0000000000..9ba3be014f
--- /dev/null
+++ b/test/built-ins/Temporal/Now/plainDate/calendar-case-insensitive.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.now.prototype.plaindate
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const arg = "jApAnEsE";
+
+const result = Temporal.Now.plainDate(arg);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/Now/plainDateTime/calendar-case-insensitive.js b/test/built-ins/Temporal/Now/plainDateTime/calendar-case-insensitive.js
new file mode 100644
index 0000000000..e3599cc28a
--- /dev/null
+++ b/test/built-ins/Temporal/Now/plainDateTime/calendar-case-insensitive.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.now.prototype.plaindatetime
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const arg = "jApAnEsE";
+
+const result = Temporal.Now.plainDateTime(arg);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/Now/zonedDateTime/calendar-case-insensitive.js b/test/built-ins/Temporal/Now/zonedDateTime/calendar-case-insensitive.js
new file mode 100644
index 0000000000..f314c9a757
--- /dev/null
+++ b/test/built-ins/Temporal/Now/zonedDateTime/calendar-case-insensitive.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.now.prototype.zoneddatetime
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const arg = "jApAnEsE";
+
+const result = Temporal.Now.zonedDateTime(arg);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/PlainDate/calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDate/calendar-case-insensitive.js
new file mode 100644
index 0000000000..298b706c9e
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDate/calendar-case-insensitive.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.plaindate.prototype.constructor
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const arg = "jApAnEsE";
+
+const result = new Temporal.PlainDate(2000, 5, 2, arg);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/PlainDate/from/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDate/from/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..eb1159dc0d
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDate/from/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,15 @@
+// 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.plaindate.prototype.from
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = Temporal.PlainDate.from(arg);
+TemporalHelpers.assertPlainDate(result, 1976, 11, "M11", 18, `Calendar created from string "${calendar}"`);
\ No newline at end of file
diff --git a/test/built-ins/Temporal/PlainDate/prototype/equals/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDate/prototype/equals/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..1913409488
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDate/prototype/equals/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// 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.plaindate.prototype.equals
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainDate(1976, 11, 18);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.equals(arg);
+assert.sameValue(result, true, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainDate/prototype/since/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDate/prototype/since/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..617fa439c3
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDate/prototype/since/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.since
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainDate(1976, 11, 18);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.since(arg);
+TemporalHelpers.assertDuration(result, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainDate/prototype/until/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDate/prototype/until/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..3cddfb4546
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDate/prototype/until/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// 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.plaindate.prototype.until
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainDate(1976, 11, 18);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.until(arg);
+TemporalHelpers.assertDuration(result, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainDate/prototype/withCalendar/calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDate/prototype/withCalendar/calendar-case-insensitive.js
new file mode 100644
index 0000000000..f98ac8611c
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDate/prototype/withCalendar/calendar-case-insensitive.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.plaindate.prototype.withcalendar
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainDate(1976, 11, 18, { id: "replace-me" });
+
+const arg = "jApAnEsE";;
+const result = instance.withCalendar(arg);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/PlainDateTime/calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDateTime/calendar-case-insensitive.js
new file mode 100644
index 0000000000..b8bb312ef5
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDateTime/calendar-case-insensitive.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.plaindatetime.prototype.constructor
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const arg = "jApAnEsE";
+
+const result = new Temporal.PlainDateTime(2000, 5, 2, 15, 23, 30, 987, 654, 321, arg);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/PlainDateTime/from/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDateTime/from/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..ef4c0770d9
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDateTime/from/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,15 @@
+// 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.plaindatetime.prototype.from
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = Temporal.PlainDateTime.from(arg);
+TemporalHelpers.assertPlainDateTime(result, 1976, 11, "M11", 18, 0, 0, 0, 0, 0, 0, `Calendar created from string "${calendar}"`);
\ No newline at end of file
diff --git a/test/built-ins/Temporal/PlainDateTime/prototype/equals/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDateTime/prototype/equals/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..6bde0037fd
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDateTime/prototype/equals/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// 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.plaindatetime.prototype.equals
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainDateTime(1976, 11, 18);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.equals(arg);
+assert.sameValue(result, true, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainDateTime/prototype/since/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDateTime/prototype/since/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..01824a81cc
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDateTime/prototype/since/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.since
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainDateTime(1976, 11, 18);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.since(arg);
+TemporalHelpers.assertDuration(result, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainDateTime/prototype/until/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDateTime/prototype/until/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..f07d2cb61c
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDateTime/prototype/until/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// 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.plaindatetime.prototype.until
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainDateTime(1976, 11, 18);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.until(arg);
+TemporalHelpers.assertDuration(result, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainDateTime/prototype/withCalendar/calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDateTime/prototype/withCalendar/calendar-case-insensitive.js
new file mode 100644
index 0000000000..c731bcb3e3
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDateTime/prototype/withCalendar/calendar-case-insensitive.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.plaindatetime.prototype.withcalendar
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainDateTime(1976, 11, 18, 15, 23, 30, 123, 456, 789, { id: "replace-me" });
+
+const arg = "jApAnEsE";;
+const result = instance.withCalendar(arg);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/PlainDateTime/prototype/withPlainDate/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainDateTime/prototype/withPlainDate/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..aae3d153b6
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDateTime/prototype/withPlainDate/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// 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.plaindatetime.prototype.withplaindate
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainDateTime(2000, 5, 2, 12, 34, 56, 987, 654, 321);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.withPlainDate(arg);
+TemporalHelpers.assertPlainDateTime(result, 1976, 11, "M11", 18, 12, 34, 56, 987, 654, 321, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainMonthDay/calendar-case-insensitive.js b/test/built-ins/Temporal/PlainMonthDay/calendar-case-insensitive.js
new file mode 100644
index 0000000000..ffb4ba82d6
--- /dev/null
+++ b/test/built-ins/Temporal/PlainMonthDay/calendar-case-insensitive.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.plainmonthday.prototype.constructor
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const arg = "jApAnEsE";
+
+const result = new Temporal.PlainMonthDay(12, 15, arg, 1972);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/PlainMonthDay/from/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainMonthDay/from/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..5ccfbc6ad3
--- /dev/null
+++ b/test/built-ins/Temporal/PlainMonthDay/from/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,15 @@
+// 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.plainmonthday.prototype.from
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const calendar = "IsO8601";
+
+const arg = { monthCode: "M11", day: 18, calendar };
+const result = Temporal.PlainMonthDay.from(arg);
+TemporalHelpers.assertPlainMonthDay(result, "M11", 18, `Calendar created from string "${calendar}"`);
\ No newline at end of file
diff --git a/test/built-ins/Temporal/PlainMonthDay/prototype/equals/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainMonthDay/prototype/equals/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..b7b355879a
--- /dev/null
+++ b/test/built-ins/Temporal/PlainMonthDay/prototype/equals/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plainmonthday.prototype.equals
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainMonthDay(11, 18);
+
+const calendar = "IsO8601";
+
+const arg = { monthCode: "M11", day: 18, calendar };
+const result = instance.equals(arg);
+assert.sameValue(result, true, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainTime/prototype/toPlainDateTime/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainTime/prototype/toPlainDateTime/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..8ae9de839e
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/toPlainDateTime/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// 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.toplaindatetime
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainTime(12, 34, 56, 987, 654, 321);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.toPlainDateTime(arg);
+TemporalHelpers.assertPlainDateTime(result, 1976, 11, "M11", 18, 12, 34, 56, 987, 654, 321, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainTime/prototype/toZonedDateTime/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainTime/prototype/toZonedDateTime/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..e439eb627f
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/toZonedDateTime/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaintime.prototype.tozoneddatetime
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainTime(12, 34, 56, 987, 654, 321);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.toZonedDateTime({ plainDate: arg, timeZone: "UTC" });
+assert.sameValue(result.epochNanoseconds, 217_168_496_987_654_321n, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainYearMonth/calendar-case-insensitive.js b/test/built-ins/Temporal/PlainYearMonth/calendar-case-insensitive.js
new file mode 100644
index 0000000000..2ae1fee560
--- /dev/null
+++ b/test/built-ins/Temporal/PlainYearMonth/calendar-case-insensitive.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.plainyearmonth.prototype.constructor
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const arg = "jApAnEsE";
+
+const result = new Temporal.PlainYearMonth(2000, 5, arg, 1);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/PlainYearMonth/from/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainYearMonth/from/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..5f7b14ba1a
--- /dev/null
+++ b/test/built-ins/Temporal/PlainYearMonth/from/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,15 @@
+// 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.plainyearmonth.prototype.from
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const calendar = "IsO8601";
+
+const arg = { year: 2019, monthCode: "M06", calendar };
+const result = Temporal.PlainYearMonth.from(arg);
+TemporalHelpers.assertPlainYearMonth(result, 2019, 6, "M06", `Calendar created from string "${calendar}"`);
\ No newline at end of file
diff --git a/test/built-ins/Temporal/PlainYearMonth/prototype/equals/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainYearMonth/prototype/equals/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..cb9d139626
--- /dev/null
+++ b/test/built-ins/Temporal/PlainYearMonth/prototype/equals/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plainyearmonth.prototype.equals
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainYearMonth(2019, 6);
+
+const calendar = "IsO8601";
+
+const arg = { year: 2019, monthCode: "M06", calendar };
+const result = instance.equals(arg);
+assert.sameValue(result, true, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainYearMonth/prototype/since/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainYearMonth/prototype/since/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..dec89eaee2
--- /dev/null
+++ b/test/built-ins/Temporal/PlainYearMonth/prototype/since/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// 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.plainyearmonth.prototype.since
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainYearMonth(2019, 6);
+
+const calendar = "IsO8601";
+
+const arg = { year: 2019, monthCode: "M06", calendar };
+const result = instance.since(arg);
+TemporalHelpers.assertDuration(result, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/PlainYearMonth/prototype/until/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/PlainYearMonth/prototype/until/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..0ad74623a1
--- /dev/null
+++ b/test/built-ins/Temporal/PlainYearMonth/prototype/until/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plainyearmonth.prototype.until
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const instance = new Temporal.PlainYearMonth(2019, 6);
+
+const calendar = "IsO8601";
+
+const arg = { year: 2019, monthCode: "M06", calendar };
+const result = instance.until(arg);
+TemporalHelpers.assertDuration(result, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/TimeZone/prototype/getInstantFor/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/TimeZone/prototype/getInstantFor/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..c96b247377
--- /dev/null
+++ b/test/built-ins/Temporal/TimeZone/prototype/getInstantFor/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// 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.timezone.prototype.getinstantfor
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.TimeZone("UTC");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.getInstantFor(arg);
+assert.sameValue(result.epochNanoseconds, 217_123_200_000_000_000n, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/TimeZone/prototype/getPlainDateTimeFor/calendar-case-insensitive.js b/test/built-ins/Temporal/TimeZone/prototype/getPlainDateTimeFor/calendar-case-insensitive.js
new file mode 100644
index 0000000000..e9071463ee
--- /dev/null
+++ b/test/built-ins/Temporal/TimeZone/prototype/getPlainDateTimeFor/calendar-case-insensitive.js
@@ -0,0 +1,14 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.timezone.prototype.getplaindatetimefor
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.TimeZone("UTC");
+
+const arg = "jApAnEsE";;
+const result = instance.getPlainDateTimeFor(new Temporal.Instant(0n), arg);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/TimeZone/prototype/getPossibleInstantsFor/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/TimeZone/prototype/getPossibleInstantsFor/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..61e434ece7
--- /dev/null
+++ b/test/built-ins/Temporal/TimeZone/prototype/getPossibleInstantsFor/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.timezone.prototype.getpossibleinstantsfor
+description: The calendar name is case-insensitive
+includes: [compareArray.js]
+features: [Temporal]
+---*/
+
+const instance = new Temporal.TimeZone("UTC");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.getPossibleInstantsFor(arg);
+assert.compareArray(result.map(i => i.epochNanoseconds), [217_123_200_000_000_000n], `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/ZonedDateTime/calendar-case-insensitive.js b/test/built-ins/Temporal/ZonedDateTime/calendar-case-insensitive.js
new file mode 100644
index 0000000000..d4d6cdbba5
--- /dev/null
+++ b/test/built-ins/Temporal/ZonedDateTime/calendar-case-insensitive.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.zoneddatetime.prototype.constructor
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const arg = "jApAnEsE";
+
+const result = new Temporal.ZonedDateTime(0n, "UTC", arg);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/ZonedDateTime/from/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/ZonedDateTime/from/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..135b340259
--- /dev/null
+++ b/test/built-ins/Temporal/ZonedDateTime/from/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,15 @@
+// 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.zoneddatetime.prototype.from
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const calendar = "IsO8601";
+
+const timeZone = new Temporal.TimeZone("UTC");
+const arg = { year: 1970, monthCode: "M01", day: 1, timeZone, calendar };
+const result = Temporal.ZonedDateTime.from(arg);
+assert.sameValue(result.calendar.id, "iso8601", `Calendar created from string "${calendar}"`);
\ No newline at end of file
diff --git a/test/built-ins/Temporal/ZonedDateTime/prototype/equals/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/ZonedDateTime/prototype/equals/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..2f7cb2c7ea
--- /dev/null
+++ b/test/built-ins/Temporal/ZonedDateTime/prototype/equals/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.zoneddatetime.prototype.equals
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const timeZone = new Temporal.TimeZone("UTC");
+const instance = new Temporal.ZonedDateTime(0n, timeZone);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1970, monthCode: "M01", day: 1, timeZone, calendar };
+const result = instance.equals(arg);
+assert.sameValue(result, true, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/ZonedDateTime/prototype/since/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/ZonedDateTime/prototype/since/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..05a024365d
--- /dev/null
+++ b/test/built-ins/Temporal/ZonedDateTime/prototype/since/argument-propertybag-calendar-case-insensitive.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.zoneddatetime.prototype.since
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const timeZone = new Temporal.TimeZone("UTC");
+const instance = new Temporal.ZonedDateTime(0n, timeZone);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1970, monthCode: "M01", day: 1, timeZone, calendar };
+const result = instance.since(arg);
+TemporalHelpers.assertDuration(result, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/ZonedDateTime/prototype/until/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/ZonedDateTime/prototype/until/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..e51382f9c9
--- /dev/null
+++ b/test/built-ins/Temporal/ZonedDateTime/prototype/until/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,18 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.zoneddatetime.prototype.until
+description: The calendar name is case-insensitive
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const timeZone = new Temporal.TimeZone("UTC");
+const instance = new Temporal.ZonedDateTime(0n, timeZone);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1970, monthCode: "M01", day: 1, timeZone, calendar };
+const result = instance.until(arg);
+TemporalHelpers.assertDuration(result, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, `Calendar created from string "${calendar}"`);
diff --git a/test/built-ins/Temporal/ZonedDateTime/prototype/withCalendar/calendar-case-insensitive.js b/test/built-ins/Temporal/ZonedDateTime/prototype/withCalendar/calendar-case-insensitive.js
new file mode 100644
index 0000000000..ef0fc6bb7a
--- /dev/null
+++ b/test/built-ins/Temporal/ZonedDateTime/prototype/withCalendar/calendar-case-insensitive.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.zoneddatetime.prototype.withcalendar
+description: Calendar names are case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UTC", { id: "replace-me" });
+
+const arg = "jApAnEsE";;
+const result = instance.withCalendar(arg);
+assert.sameValue(result.calendar.id, "japanese", "Calendar is case-insensitive");
diff --git a/test/built-ins/Temporal/ZonedDateTime/prototype/withPlainDate/argument-propertybag-calendar-case-insensitive.js b/test/built-ins/Temporal/ZonedDateTime/prototype/withPlainDate/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..efe768386a
--- /dev/null
+++ b/test/built-ins/Temporal/ZonedDateTime/prototype/withPlainDate/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,17 @@
+// 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.zoneddatetime.prototype.withplaindate
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const timeZone = new Temporal.TimeZone("UTC");
+const instance = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, timeZone);
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.withPlainDate(arg);
+assert.sameValue(result.epochNanoseconds, 217_129_600_000_000_000n, `Calendar created from string "${calendar}"`);
diff --git a/test/intl402/Temporal/Calendar/prototype/era/argument-propertybag-calendar-case-insensitive.js b/test/intl402/Temporal/Calendar/prototype/era/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..3f2e14a44a
--- /dev/null
+++ b/test/intl402/Temporal/Calendar/prototype/era/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.era
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.era(arg);
+assert.sameValue(result, undefined, `Calendar created from string "${calendar}"`);
diff --git a/test/intl402/Temporal/Calendar/prototype/eraYear/argument-propertybag-calendar-case-insensitive.js b/test/intl402/Temporal/Calendar/prototype/eraYear/argument-propertybag-calendar-case-insensitive.js
new file mode 100644
index 0000000000..17f3a91ded
--- /dev/null
+++ b/test/intl402/Temporal/Calendar/prototype/eraYear/argument-propertybag-calendar-case-insensitive.js
@@ -0,0 +1,16 @@
+// 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.calendar.prototype.erayear
+description: The calendar name is case-insensitive
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Calendar("iso8601");
+
+const calendar = "IsO8601";
+
+const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
+const result = instance.eraYear(arg);
+assert.sameValue(result, undefined, `Calendar created from string "${calendar}"`);