Thorough tests for ISO-like calendar math

Splits test/thorough/gregorian.mjs into two new test files:

- calendarisolike.mjs tests that the year and month differences for the
  four ISO-like calendars are equal to the same differences calculated
  in the ISO calendar.

- calendardaymath.mjs tests that week and day differences for all non-
  ISO calendars (except, temporarily, 'chinese' and 'dangi') are equal
  to the same differences calculated in the ISO calendar. (Days are
  always equivalent, and weeks are always 7 days in all currently
  supported calendars.)

This is in order to test the simplest invariants in other non-ISO
calendars and not just 'gregory'.

Author: ptomato

polyfill/test/thorough/all.sh

@@ -15,13 +15,14 @@ cd $(dirname $0)
 interpreter=${1-node}
 there_were_errors=0
 for test in \
+  calendardaymath \
+  calendarisolike \
   dateaddition \
   datedifference \
   datetimeaddition \
   datetimedifference \
   datetimerounding \
   durationaddition \
-  gregorian \
   instantaddition \
   instantdifference \
   instantrounding \

polyfill/test/thorough/calendardaymath.mjs

@@ -0,0 +1,60 @@
+import {
+  assertDurationsEqual,
+  assertTemporalEqual,
+  getProgressBar,
+  makeDateCases,
+  temporalImpl as T,
+  time
+} from './support.mjs';
+
+const largestUnits = [{ largestUnit: 'weeks' }, { largestUnit: 'days' }];
+// 'chinese' and 'dangi' are temporarily omitted because there are some dates
+// that the current version of ICU4C can't handle well enough to calculate the
+// snapshots
+const calendars = [
+  'buddhist',
+  'coptic',
+  'ethioaa',
+  'ethiopic',
+  'gregory',
+  'hebrew',
+  'indian',
+  'islamic-civil',
+  'islamic-tbla',
+  'islamic-umalqura',
+  'japanese',
+  'persian',
+  'roc'
+];
+
+const interestingCases = makeDateCases();
+const total = calendars.length * ((interestingCases.length * (interestingCases.length - 1)) / 2);
+
+await time((start) => {
+  const progress = getProgressBar(start, total);
+
+  for (const calendar of calendars) {
+    for (const [oneISO, str1] of interestingCases) {
+      const one = oneISO.withCalendar(calendar);
+      for (const [twoISO, str2] of interestingCases) {
+        if (T.PlainDate.compare(oneISO, twoISO) === 1) continue;
+        progress.tick(1, { test: `${calendar} ${str1} : ${str2}` });
+        const two = twoISO.withCalendar(calendar);
+        for (const opts of largestUnits) {
+          const dif = oneISO.until(twoISO, opts);
+          assertDurationsEqual(twoISO.since(oneISO, opts), dif, `${str1} and ${str2} symmetric in ${opts.largestUnit}`);
+          assertDurationsEqual(one.until(two, opts), dif, `${str1} until ${str2} ${opts.largestUnit}`);
+          assertDurationsEqual(one.since(two, opts), dif.negated(), `${str1} since ${str2} ${opts.largestUnit}`);
+          assertDurationsEqual(two.until(one, opts), dif.negated(), `${str2} until ${str1} ${opts.largestUnit}`);
+          assertDurationsEqual(two.since(one, opts), dif, `${str2} since ${str1} ${opts.largestUnit}`);
+          assertTemporalEqual(one.add(dif), two, `${str1} + ${dif} = ${str2}`);
+          assertTemporalEqual(one.subtract(dif.negated()), two, `${str1} - -${dif} = ${str2}`);
+          assertTemporalEqual(two.add(dif.negated()), one, `${str2} + -${dif} = ${str1}`);
+          assertTemporalEqual(two.subtract(dif), one, `${str2} - ${dif} = ${str1}`);
+        }
+      }
+    }
+  }
+
+  return total;
+});

polyfill/test/thorough/calendarisolike.mjs

@@ -0,0 +1,43 @@
+import {
+  assertDurationsEqual,
+  assertTemporalEqual,
+  getProgressBar,
+  makeDateCases,
+  temporalImpl as T,
+  time
+} from './support.mjs';
+
+const largestUnits = [{ largestUnit: 'years' }, { largestUnit: 'months' }];
+const calendars = ['buddhist', 'gregory', 'japanese', 'roc'];
+
+const interestingCases = makeDateCases();
+const total = calendars.length * ((interestingCases.length * (interestingCases.length - 1)) / 2);
+
+await time((start) => {
+  const progress = getProgressBar(start, total);
+
+  for (const calendar of calendars) {
+    for (const [oneISO, str1] of interestingCases) {
+      const one = oneISO.withCalendar(calendar);
+      for (const [twoISO, str2] of interestingCases) {
+        if (T.PlainDate.compare(oneISO, twoISO) === 1) continue;
+        progress.tick(1, { test: `${calendar} ${str1} : ${str2}` });
+        const two = twoISO.withCalendar(calendar);
+        for (const opts of largestUnits) {
+          const dif1 = oneISO.until(twoISO, opts);
+          const dif2 = twoISO.since(oneISO, opts);
+          assertDurationsEqual(one.until(two, opts), dif1, `${str1} until ${str2} ${opts.largestUnit}`);
+          assertDurationsEqual(one.since(two, opts), dif1.negated(), `${str1} since ${str2} ${opts.largestUnit}`);
+          assertDurationsEqual(two.until(one, opts), dif2.negated(), `${str2} until ${str1} ${opts.largestUnit}`);
+          assertDurationsEqual(two.since(one, opts), dif2, `${str2} since ${str1} ${opts.largestUnit}`);
+          assertTemporalEqual(one.add(dif1), two, `${str1} + ${dif1} = ${str2}`);
+          assertTemporalEqual(one.subtract(dif1.negated()), two, `${str1} - -${dif1} = ${str2}`);
+          assertTemporalEqual(two.add(dif2.negated()), one, `${str2} + -${dif2} = ${str1}`);
+          assertTemporalEqual(two.subtract(dif2), one, `${str2} - ${dif2} = ${str1}`);
+        }
+      }
+    }
+  }
+
+  return total;
+});