lib: Fix timeformat.parseShortDate()

Do the "strip off time and set to midnight" step already for the
reference Date input of parse(). Substracting it afterwards previously
caused the returned date to be off by one day for time zones other than
UTC.

Add `test_timeformat_timezones()` pytest to cover various time zones.

pkg/base1/test-timeformat.ts

@@ -124,10 +124,7 @@ QUnit.test("firstDayOfWeek", assert => {
     assert.equal(timeformat.firstDayOfWeek(), 1);
 });
 
-// FIXME: This test is currently time zone dependent; parseShortDate() always
-// interprets its argument as midnight UTC instead of local time; so it's even
-// off by a day for any TZ east of UTC.
-QUnit.skip("parsing", assert => {
+QUnit.test("parsing", assert => {
     cockpit.language = "en";
     const en = timeformat.parseShortDate("1/20/2024");
     assert.equal(en.getDate(), 20);

pkg/lib/timeformat.ts

@@ -52,12 +52,10 @@ export const distanceToNow = (t: Time, addSuffix?: boolean): string => formatDis
 
 // Parse a string localized date like 30.06.21 to a Date Object
 export function parseShortDate(dateStr: string): Date {
-    const parsed = parse(dateStr, dateShortFormat(), new Date());
-
-    // Strip time which may cause bugs in calendar
-    const time = parsed.getTime();
-    const timePortion = time % (3600 * 1000 * 24);
-    return new Date(time - timePortion);
+    // strip off time (i.e. set to midnight), to avoid confusing calendar widgets
+    const now = new Date();
+    const today = new Date(now.getFullYear(), now.getMonth(), now.getDate());
+    return parse(dateStr, dateShortFormat(), today);
 }
 
 /***

test/pytest/test_browser.py

@@ -46,3 +46,22 @@ def test_browser(html):
     subprocess.run(['test/common/tap-cdp', f'{BUILDDIR}/test-server',
                     sys.executable, '-m', *coverage, 'cockpit.bridge', '--debug',
                     f'./qunit/{html}'], check=True, stderr=subprocess.STDOUT)
+
+
+# run test-timeformat.ts in different time zones: west/UTC/east
+@pytest.mark.parametrize('tz', ['America/Toronto', 'Europe/London', 'UTC', 'Europe/Berlin', 'Australia/Sydney'])
+def test_timeformat_timezones(tz):
+    if not os.path.exists(f'{BUILDDIR}/test-server'):
+        pytest.skip('no test-server')
+    # this doesn't get built in rpm/deb package build environments, similar to test_browser()
+    built_test = './qunit/base1/test-timeformat.html'
+    if not os.path.exists(built_test):
+        pytest.skip(f'{built_test} not found')
+
+    env = os.environ.copy()
+    env['TZ'] = tz
+
+    # Merge 2>&1 so that pytest displays an interleaved log
+    subprocess.run(['test/common/tap-cdp', f'{BUILDDIR}/test-server',
+                    sys.executable, '-m', 'cockpit.bridge', '--debug',
+                    built_test], check=True, stderr=subprocess.STDOUT, env=env)