Everywhere: Hoist the Libraries folder to the top-level

Author: https://github.com/trflynn89
Commit: https://github.com/LadybirdBrowser/ladybird/commit/93712b24bf2
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2256
Reviewed-by: https://github.com/sideshowbarker

Libraries/LibJS/Tests/builtins/Temporal/Now/Now.plainDateISO.js

@@ -0,0 +1,57 @@
+describe("correct behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.Now.plainDateISO).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        const plainDate = Temporal.Now.plainDateISO();
+        expect(plainDate).toBeInstanceOf(Temporal.PlainDate);
+        expect(plainDate.calendar.id).toBe("iso8601");
+    });
+
+    test("custom time zone", () => {
+        const timeZone = {
+            getOffsetNanosecondsFor() {
+                return 86399999999999;
+            },
+        };
+        const plainDate = Temporal.Now.plainDateISO("UTC");
+        const plainDateWithOffset = Temporal.Now.plainDateISO(timeZone);
+        if (plainDate.dayOfYear === plainDate.daysInYear) {
+            expect(plainDateWithOffset.year).toBe(plainDate.year + 1);
+            expect(plainDateWithOffset.month).toBe(1);
+            expect(plainDateWithOffset.day).toBe(1);
+        } else {
+            expect(plainDateWithOffset.year).toBe(plainDate.year);
+            if (plainDate.day === plainDate.daysInMonth) {
+                expect(plainDateWithOffset.month).toBe(plainDate.month + 1);
+                expect(plainDateWithOffset.day).toBe(1);
+            } else {
+                expect(plainDateWithOffset.month).toBe(plainDate.month);
+                expect(plainDateWithOffset.day).toBe(plainDate.day + 1);
+            }
+        }
+    });
+
+    test("cannot have a time zone with more than a day", () => {
+        [86400000000000, -86400000000000, 86400000000001, 86400000000002].forEach(offset => {
+            const timeZone = {
+                getOffsetNanosecondsFor() {
+                    return offset;
+                },
+            };
+            expect(() => Temporal.Now.plainDateISO(timeZone)).toThrowWithMessage(
+                RangeError,
+                "Invalid offset nanoseconds value, must be in range -86400 * 10^9 + 1 to 86400 * 10^9 - 1"
+            );
+        });
+    });
+});
+
+describe("errors", () => {
+    test("custom time zone doesn't have a getOffsetNanosecondsFor function", () => {
+        expect(() => {
+            Temporal.Now.plainDateISO({});
+        }).toThrowWithMessage(TypeError, "getOffsetNanosecondsFor is undefined");
+    });
+});