Add tests for RoundDuration when unit is "month" and the fractionalDays sign gets flipped

test/built-ins/Temporal/Duration/prototype/round/fractional-days-with-flipped-sign-1.js

@@ -0,0 +1,145 @@
+// Copyright (C) 2023 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.duration.prototype.round
+description: >
+  Fractional days parts correctly handled when weeksInDays has a flipped sign.
+info: |
+  RoundDuration ( ... )
+
+  RoundDuration is called with months=1, weeks=1, days=4, and hours=12.
+
+  Step 4.c:
+    Let fractionalDays be days + nanoseconds / nsPerDay.
+
+    With days=4 and hours=12, this computes fractionalDays=4.5
+
+  Step 8.e:
+    Let yearsMonthsLater be ? CalendarDateAdd(calendar, plainRelativeTo, yearsMonths, undefined, dateAdd).
+
+    The calendar's `dateAdd` method is overridden to change the duration from
+    "P1M" to "P5D".
+
+  Step 8.g:
+    Let yearsMonthsWeeksLater be ? CalendarDateAdd(calendar, plainRelativeTo, yearsMonthsWeeks, undefined, dateAdd).
+
+    The calendar's `dateAdd` method is overridden to change the duration from
+    "P1M1W" to "P0D".
+
+  Step 8.h:
+    Let weeksInDays be DaysUntil(yearsMonthsLater, yearsMonthsWeeksLater).
+
+    This computes weeksInDays=-5 with the modified durations from steps 8.e, 8.g.
+
+  Step 8.j:
+    Set fractionalDays to fractionalDays + weeksInDays.
+
+    With fractionalDays=4.5 and weeksInDays=-5, this sets fractionalDays to -0.5.
+
+  Step 8.k:
+    If fractionalDays < 0, let sign be -1; else, let sign be 1.
+
+    fractionalDays is -0.5, so `sign` is set to -1.
+
+  Step 8.m:
+    Let moveResult be ? MoveRelativeDate(calendar, plainRelativeTo, oneMonth, dateAdd).
+
+    The calendar's `dateAdd` method is overridden to change the duration from
+    "-P1M" to "P1D".
+
+  Step 8.o:
+    Let oneMonthDays be moveResult.[[Days]].
+
+    This computes oneMonthDays=1 with the modified duration from step 8.m.
+
+  Step 8.p:
+    Repeat, while abs(fractionalDays) ≥ abs(oneMonthDays),
+
+    With fractionalDays=-0.5 and oneMonthDays=1, abs(-0.5) ≥ abs(1) is false, so
+    the loop is not entered.
+
+  Step 8.q:
+    Let fractionalMonths be months + fractionalDays / abs(oneMonthDays).
+
+    With months=1, fractionalDays=-0.5, and oneMonthDays=1, this computes
+    fractionalMonths=0.5.
+
+  Step 8.r:
+    Set months to RoundNumberToIncrement(fractionalMonths, increment, roundingMode).
+
+    With fractionalMonths=0.5, increment=1, and roundingMode="ceil", this
+    computes months=ceil(0.5)=1.
+
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+let duration = Temporal.Duration.from({
+  months: 1,
+  weeks: 1,
+  days: 4,
+  hours: 12,
+});
+
+let expectedCalls = [
+  // RoundDuration
+  // 8.b Let yearsMonths be ! CreateTemporalDuration(years, months, 0, 0, 0, 0, 0, 0, 0, 0).
+  // 8.e Let yearsMonthsLater be ? CalendarDateAdd(calendar, plainRelativeTo, yearsMonths, undefined, dateAdd).
+  {
+    expected: {months: 1},
+    override: {days: 5},
+  },
+
+  // RoundDuration
+  // 8.f Let yearsMonthsWeeks be ! CreateTemporalDuration(years, months, weeks, 0, 0, 0, 0, 0, 0, 0).
+  // 8.g Let yearsMonthsWeeksLater be ? CalendarDateAdd(calendar, plainRelativeTo, yearsMonthsWeeks, undefined, dateAdd).
+  {
+    expected: {months: 1, weeks: 1},
+    override: {days: 0},
+  },
+
+  // RoundDuration
+  // 8.l Let oneMonth be ! CreateTemporalDuration(0, sign, 0, 0, 0, 0, 0, 0, 0, 0).
+  // 8.m Let moveResult be ? MoveRelativeDate(calendar, plainRelativeTo, oneMonth, dateAdd).
+  {
+    expected: {months: -1},
+    override: {days: 1},
+  },
+
+  // BalanceDateDurationRelative
+  // 8 Let oneMonth be ! CreateTemporalDuration(0, sign, 0, 0, 0, 0, 0, 0, 0, 0).
+  // 12.c Let moveResult be ? MoveRelativeDate(calendar, plainRelativeTo, oneMonth, dateAdd).
+  {
+    expected: {months: 1},
+    override: {months: 1},
+  },
+];
+
+let calendar = new class extends Temporal.Calendar {
+  dateAdd(date, duration, options) {
+    assert(expectedCalls.length > 0, "too many dateAdd calls");
+
+    let {expected, override} = expectedCalls.shift();
+    TemporalHelpers.assertDurationsEqual(duration, Temporal.Duration.from(expected));
+
+    return super.dateAdd(date, override, options);
+  }
+}("iso8601");
+
+let relativeTo = new Temporal.PlainDate(2020, 1, 1, calendar);
+
+let result = duration.round({
+  smallestUnit: "months",
+  roundingMode: "ceil",
+  roundingIncrement: 1,
+  relativeTo,
+});
+
+assert.sameValue(expectedCalls.length, 0, "All expected dateAdd calls happened");
+
+let expected = Temporal.Duration.from({
+  months: 1,
+});
+
+TemporalHelpers.assertDurationsEqual(result, expected, "Rounded duration is P1M");

test/built-ins/Temporal/Duration/prototype/round/fractional-days-with-flipped-sign-2.js

@@ -0,0 +1,179 @@
+// Copyright (C) 2023 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.duration.prototype.round
+description: >
+  Fractional days parts correctly handled when weeksInDays has a flipped sign.
+info: |
+  RoundDuration ( ... )
+
+  RoundDuration is called with months=1, weeks=1, days=4, and hours=12.
+
+  Step 4.c:
+    Let fractionalDays be days + nanoseconds / nsPerDay.
+
+    With days=4 and hours=12, this computes fractionalDays=4.5
+
+  Step 8.e:
+    Let yearsMonthsLater be ? CalendarDateAdd(calendar, plainRelativeTo, yearsMonths, undefined, dateAdd).
+
+    The calendar's `dateAdd` method is overridden to change the duration from
+    "P1M" to "P6D".
+
+  Step 8.g:
+    Let yearsMonthsWeeksLater be ? CalendarDateAdd(calendar, plainRelativeTo, yearsMonthsWeeks, undefined, dateAdd).
+
+    The calendar's `dateAdd` method is overridden to change the duration from
+    "P1M1W" to "P0D".
+
+  Step 8.h:
+    Let weeksInDays be DaysUntil(yearsMonthsLater, yearsMonthsWeeksLater).
+
+    This computes weeksInDays=-6 with the modified durations from steps 8.e, 8.g.
+
+  Step 8.j:
+    Set fractionalDays to fractionalDays + weeksInDays.
+
+    With fractionalDays=4.5 and weeksInDays=-6, this sets fractionalDays to -1.5.
+
+  Step 8.k:
+    If fractionalDays < 0, let sign be -1; else, let sign be 1.
+
+    fractionalDays is -1.5, so `sign` is set to -1.
+
+  Step 8.m:
+    Let moveResult be ? MoveRelativeDate(calendar, plainRelativeTo, oneMonth, dateAdd).
+
+    The calendar's `dateAdd` method is overridden to change the duration from
+    "-P1M" to "-P1D".
+
+  Step 8.o:
+    Let oneMonthDays be moveResult.[[Days]].
+
+    This computes oneMonthDays=-1 with the modified duration from step 8.m.
+
+  Step 8.p:
+    Repeat, while abs(fractionalDays) ≥ abs(oneMonthDays),
+
+    With fractionalDays=-1.5 and oneMonthDays=-1, abs(-1.5) ≥ abs(-1) is true,
+    so the loop is entered.
+
+  Step 8.p.i:
+    Set months to months + sign.
+
+    With months=1 and sign=-1, this sets months=0.
+
+  Step 8.p.ii:
+    Set fractionalDays to fractionalDays - oneMonthDays.
+
+    With fractionalDays=-1.5 and oneMonthDays=-1, this sets fractionalDays=-0.5.
+
+  Step 8.p.iii:
+    Set moveResult to ? MoveRelativeDate(calendar, plainRelativeTo, oneMonth, dateAdd).
+
+    The calendar's `dateAdd` method is overridden to change the duration from
+    "-P1M" to "-P1D".
+
+  Step 8.p.iv:
+    Set oneMonthDays to moveResult.[[Days]].
+
+    This computes oneMonthDays=-1 with the modified duration from step 8.p.iii.
+
+  Step 8.p:
+    Repeat, while abs(fractionalDays) ≥ abs(oneMonthDays),
+
+    With fractionalDays=-0.5 and oneMonthDays=-1, abs(-0.5) ≥ abs(-1) is false,
+    so the loop is not entered again.
+
+  Step 8.q:
+    Let fractionalMonths be months + fractionalDays / abs(oneMonthDays).
+
+    With months=0, fractionalDays=-0.5, and oneMonthDays=1, this computes
+    fractionalMonths=-0.5.
+
+  Step 8.r:
+    Set months to RoundNumberToIncrement(fractionalMonths, increment, roundingMode).
+
+    With fractionalMonths=-0.5, increment=1, and roundingMode="floor", this
+    computes months=floor(-0.5)=-1.
+
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+let duration = Temporal.Duration.from({
+  months: 1,
+  weeks: 1,
+  days: 4,
+  hours: 12,
+});
+
+let expectedCalls = [
+  // RoundDuration
+  // 8.b Let yearsMonths be ! CreateTemporalDuration(years, months, 0, 0, 0, 0, 0, 0, 0, 0).
+  // 8.e Let yearsMonthsLater be ? CalendarDateAdd(calendar, plainRelativeTo, yearsMonths, undefined, dateAdd).
+  {
+    expected: {months: 1},
+    override: {days: 6},
+  },
+
+  // RoundDuration
+  // 8.f Let yearsMonthsWeeks be ! CreateTemporalDuration(years, months, weeks, 0, 0, 0, 0, 0, 0, 0).
+  // 8.g Let yearsMonthsWeeksLater be ? CalendarDateAdd(calendar, plainRelativeTo, yearsMonthsWeeks, undefined, dateAdd).
+  {
+    expected: {months: 1, weeks: 1},
+    override: {days: 0},
+  },
+
+  // RoundDuration
+  // 8.l Let oneMonth be ! CreateTemporalDuration(0, sign, 0, 0, 0, 0, 0, 0, 0, 0).
+  // 8.m Let moveResult be ? MoveRelativeDate(calendar, plainRelativeTo, oneMonth, dateAdd).
+  {
+    expected: {months: -1},
+    override: {days: -1},
+  },
+
+  // RoundDuration
+  // 8.p.iii Set moveResult to ? MoveRelativeDate(calendar, plainRelativeTo, oneMonth, dateAdd).
+  {
+    expected: {months: -1},
+    override: {days: -1},
+  },
+
+  // BalanceDateDurationRelative
+  // 8 Let oneMonth be ! CreateTemporalDuration(0, sign, 0, 0, 0, 0, 0, 0, 0, 0).
+  // 12.c Let moveResult be ? MoveRelativeDate(calendar, plainRelativeTo, oneMonth, dateAdd).
+  {
+    expected: {months: -1},
+    override: {months: -1},
+  },
+];
+
+let calendar = new class extends Temporal.Calendar {
+  dateAdd(date, duration, options) {
+    assert(expectedCalls.length > 0, "too many dateAdd calls");
+
+    let {expected, override} = expectedCalls.shift();
+    TemporalHelpers.assertDurationsEqual(duration, Temporal.Duration.from(expected));
+
+    return super.dateAdd(date, override, options);
+  }
+}("iso8601");
+
+let relativeTo = new Temporal.PlainDate(2020, 1, 1, calendar);
+
+let result = duration.round({
+  smallestUnit: "months",
+  roundingMode: "floor",
+  roundingIncrement: 1,
+  relativeTo,
+});
+
+assert.sameValue(expectedCalls.length, 0, "All expected dateAdd calls happened");
+
+let expected = Temporal.Duration.from({
+  months: -1,
+});
+
+TemporalHelpers.assertDurationsEqual(result, expected, "Rounded duration is -P1M");