4 files changed, 40 insertions, 4 deletions
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.from.js b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.from.js
index 5230c153a7..9cc4432aa7 100644
--- a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.from.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.from.js
@@ -96,7 +96,7 @@ describe("correct behavior", () => {
     });
 
     test("PlainDateTime string argument", () => {
-        const plainDateTime = Temporal.PlainDateTime.from("2021-07-06T23:42:01Z");
+        const plainDateTime = Temporal.PlainDateTime.from("2021-07-06T23:42:01");
         expect(plainDateTime.year).toBe(2021);
         expect(plainDateTime.month).toBe(7);
         expect(plainDateTime.day).toBe(6);
@@ -177,4 +177,13 @@ describe("errors", () => {
             Temporal.PlainDateTime.from(zonedDateTime);
         }).toThrowWithMessage(TypeError, "null is not a function");
     });
+
+    test("string must not contain a UTC designator", () => {
+        expect(() => {
+            Temporal.PlainDateTime.from("2021-07-06T23:42:01Z");
+        }).toThrowWithMessage(
+            RangeError,
+            "Invalid date time string '2021-07-06T23:42:01Z': must not contain a UTC designator"
+        );
+    });
 });
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainMonthDay/PlainMonthDay.from.js b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainMonthDay/PlainMonthDay.from.js
index 99f6ce55fb..78388845c3 100644
--- a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainMonthDay/PlainMonthDay.from.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainMonthDay/PlainMonthDay.from.js
@@ -42,7 +42,7 @@ describe("correct behavior", () => {
     });
 
     test("from date time string", () => {
-        const plainMonthDay = Temporal.PlainMonthDay.from("2021-07-06T23:42:01Z");
+        const plainMonthDay = Temporal.PlainMonthDay.from("2021-07-06T23:42:01");
         expect(plainMonthDay.monthCode).toBe("M07");
         expect(plainMonthDay.day).toBe(6);
     });
@@ -66,4 +66,13 @@ describe("errors", () => {
             Temporal.PlainMonthDay.from("foo");
         }).toThrowWithMessage(RangeError, "Invalid month day string 'foo'");
     });
+
+    test("string must not contain a UTC designator", () => {
+        expect(() => {
+            Temporal.PlainMonthDay.from("2021-07-06T23:42:01Z");
+        }).toThrowWithMessage(
+            RangeError,
+            "Invalid month day string '2021-07-06T23:42:01Z': must not contain a UTC designator"
+        );
+    });
 });
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainTime/PlainTime.from.js b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainTime/PlainTime.from.js
index 7f3069c393..d549c5272b 100644
--- a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainTime/PlainTime.from.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainTime/PlainTime.from.js
@@ -38,7 +38,7 @@ describe("correct behavior", () => {
     });
 
     test("PlainTime string argument", () => {
-        const createdPlainTime = Temporal.PlainTime.from("2021-08-27T18:44:11Z");
+        const createdPlainTime = Temporal.PlainTime.from("2021-08-27T18:44:11");
         expect(createdPlainTime.hour).toBe(18);
         expect(createdPlainTime.minute).toBe(44);
         expect(createdPlainTime.second).toBe(11);
@@ -55,4 +55,13 @@ describe("errors", () => {
             Temporal.PlainTime.from(zonedDateTime);
         }).toThrowWithMessage(TypeError, "null is not a function");
     });
+
+    test("string must not contain a UTC designator", () => {
+        expect(() => {
+            Temporal.PlainTime.from("2021-07-06T23:42:01Z");
+        }).toThrowWithMessage(
+            RangeError,
+            "Invalid time string '2021-07-06T23:42:01Z': must not contain a UTC designator"
+        );
+    });
 });
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainYearMonth/PlainYearMonth.from.js b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainYearMonth/PlainYearMonth.from.js
index 0ba572a08b..78a1fbc031 100644
--- a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainYearMonth/PlainYearMonth.from.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainYearMonth/PlainYearMonth.from.js
@@ -63,7 +63,7 @@ describe("correct behavior", () => {
     });
 
     test("from date time string", () => {
-        const plainYearMonth = Temporal.PlainYearMonth.from("2021-07-06T23:42:01Z");
+        const plainYearMonth = Temporal.PlainYearMonth.from("2021-07-06T23:42:01");
         expect(plainYearMonth.year).toBe(2021);
         expect(plainYearMonth.month).toBe(7);
         expect(plainYearMonth.monthCode).toBe("M07");
@@ -92,4 +92,13 @@ describe("errors", () => {
             Temporal.PlainYearMonth.from("foo");
         }).toThrowWithMessage(RangeError, "Invalid year month string 'foo'");
     });
+
+    test("string must not contain a UTC designator", () => {
+        expect(() => {
+            Temporal.PlainYearMonth.from("2021-07-06T23:42:01Z");
+        }).toThrowWithMessage(
+            RangeError,
+            "Invalid year month string '2021-07-06T23:42:01Z': must not contain a UTC designator"
+        );
+    });
 });