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LibJS: Fix the Now.plainDateTime in case they go over a year boundary

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Since years don't have a constant amount of seconds because they can be
leap years no constant will work in all cases. We now test a timezone in
both the positive and negative direction and check that at least one
worked. Assuming years are at least 2 days long this will always pass
at least one test.
This commit is contained in:
davidot 2021-12-31 11:17:41 +01:00 • committed by Linus Groh
parent c296df6b58
commit c0a3b1467c
2 changed files with 93 additions and 22 deletions
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58
Userland/Libraries/LibJS/Tests/builtins/Temporal/Now/Now.plainDateTime.js
View file

@ -10,7 +10,26 @@ describe("correct behavior", () => {
expect(plainDateTime.calendar).toBe(calendar);
});
test("custom time zone", () => {
const plainDateTimeToEpochSeconds = plainDateTime =>
(plainDateTime.year - 1970) * 31_556_952 +
plainDateTime.dayOfYear * 86_400 +
plainDateTime.hour * 3_600 +
plainDateTime.minute * 60 +
plainDateTime.second +
plainDateTime.millisecond / 1_000 +
plainDateTime.microsecond / 1_000_000 +
plainDateTime.nanosecond / 1_000_000_000;
let timeZoneTested = false;
// Note: We test both positive and negative timezones because one might cross a year boundary.
// Since a year does not have a fixed amount of seconds because it can be a leap year,
// we cannot have a correct constant for seconds per year which is always correct.
// However, by assuming years are at least 2 days long we can simply try the positive
// and negative timezones and skip one if we jump the year. To ensure at least one is
// tested we have the timeZoneTested which is only set to true if one of the tests passed.
test("custom time zone positive", () => {
const calendar = new Temporal.Calendar("iso8601");
const timeZone = {
getOffsetNanosecondsFor() {
@ -18,24 +37,41 @@ describe("correct behavior", () => {
},
};
const plainDateTimeToEpochSeconds = plainDateTime =>
(plainDateTime.year - 1970) * 31_556_952 +
plainDateTime.dayOfYear * 86_400 +
plainDateTime.hour * 3_600 +
plainDateTime.minute * 60 +
plainDateTime.second +
plainDateTime.millisecond / 1_000 +
plainDateTime.microsecond / 1_000_000 +
plainDateTime.nanosecond / 1_000_000_000;
const plainDateTime = Temporal.Now.plainDateTime(calendar);
const plainDateTimeWithOffset = Temporal.Now.plainDateTime(calendar, timeZone);
if (plainDateTime.year !== plainDateTimeWithOffset.year) return;
// Let's hope the duration between the above two lines is less than a second :^)
const differenceSeconds =
plainDateTimeToEpochSeconds(plainDateTimeWithOffset) -
plainDateTimeToEpochSeconds(plainDateTime);
expect(Math.floor(differenceSeconds)).toBe(86400);
timeZoneTested = true;
});
test("custom time zone negative", () => {
const calendar = new Temporal.Calendar("iso8601");
const timeZone = {
getOffsetNanosecondsFor() {
return -86400000000000;
},
};
const plainDateTime = Temporal.Now.plainDateTime(calendar);
const plainDateTimeWithOffset = Temporal.Now.plainDateTime(calendar, timeZone);
if (plainDateTime.year !== plainDateTimeWithOffset.year) return;
// Let's hope the duration between the above two lines is less than a second :^)
const differenceSeconds =
plainDateTimeToEpochSeconds(plainDateTimeWithOffset) -
plainDateTimeToEpochSeconds(plainDateTime);
expect(Math.floor(differenceSeconds)).toBe(-86400);
timeZoneTested = true;
});
expect(timeZoneTested).toBeTrue();
});
describe("errors", () => {

57
Userland/Libraries/LibJS/Tests/builtins/Temporal/Now/Now.plainDateTimeISO.js
View file

@ -9,31 +9,66 @@ describe("correct behavior", () => {
expect(plainDateTime.calendar.id).toBe("iso8601");
});
test("custom time zone", () => {
const plainDateTimeToEpochSeconds = plainDateTime =>
(plainDateTime.year - 1970) * 31_556_952 +
plainDateTime.dayOfYear * 86_400 +
plainDateTime.hour * 3_600 +
plainDateTime.minute * 60 +
plainDateTime.second +
plainDateTime.millisecond / 1_000 +
plainDateTime.microsecond / 1_000_000 +
plainDateTime.nanosecond / 1_000_000_000;
let timeZoneTested = false;
// Note: We test both positive and negative timezones because one might cross a year boundary.
// Since a year does not have a fixed amount of seconds because it can be a leap year,
// we cannot have a correct constant for seconds per year which is always correct.
// However, by assuming years are at least 2 days long we can simply try the positive
// and negative timezones and skip one if we jump the year. To ensure at least one is
// tested we have the timeZoneTested which is only set to true if one of the tests passed.
test("custom time zone positive", () => {
const timeZone = {
getOffsetNanosecondsFor() {
return 86400000000000;
},
};
const plainDateTimeToEpochSeconds = plainDateTime =>
(plainDateTime.year - 1970) * 31_556_952 +
plainDateTime.dayOfYear * 86_400 +
plainDateTime.hour * 3_600 +
plainDateTime.minute * 60 +
plainDateTime.second +
plainDateTime.millisecond / 1_000 +
plainDateTime.microsecond / 1_000_000 +
plainDateTime.nanosecond / 1_000_000_000;
const plainDateTime = Temporal.Now.plainDateTimeISO();
const plainDateTimeWithOffset = Temporal.Now.plainDateTimeISO(timeZone);
if (plainDateTime.year !== plainDateTimeWithOffset.year) return;
// Let's hope the duration between the above two lines is less than a second :^)
const differenceSeconds =
plainDateTimeToEpochSeconds(plainDateTimeWithOffset) -
plainDateTimeToEpochSeconds(plainDateTime);
expect(Math.floor(differenceSeconds)).toBe(86400);
timeZoneTested = true;
});
test("custom time zone negative", () => {
const timeZone = {
getOffsetNanosecondsFor() {
return -86400000000000;
},
};
const plainDateTime = Temporal.Now.plainDateTimeISO();
const plainDateTimeWithOffset = Temporal.Now.plainDateTimeISO(timeZone);
if (plainDateTime.year !== plainDateTimeWithOffset.year) return;
// Let's hope the duration between the above two lines is less than a second :^)
const differenceSeconds =
plainDateTimeToEpochSeconds(plainDateTimeWithOffset) -
plainDateTimeToEpochSeconds(plainDateTime);
expect(Math.floor(differenceSeconds)).toBe(-86400);
timeZoneTested = true;
});
expect(timeZoneTested).toBeTrue();
});
describe("errors", () => {