[Apple-Mobile][Globalization] Refactoring of CalendarData.iOS and new DateTimeFormatInfo* tests (#102464)

* enable ShortDatePattern tests + refactor

* LongDatePattern correct format

* LongDatePattern tests

* fix EnumDatePatterns AddRange for Apple Hybrid

* remove duplicate invariant ShorDatePattern test

* remove duplicate en-US LongDatePattern case

* MonthDayPattern test cases

* add _ICU suffix to DatePattern names

* DayNames ICU test cases

* AbbreviatedDayNames ICU tests

* Move GetCalendarInfoNative to EnumCalendarInfo ICU

* MonthNames test suit for ICU

* AbbreviatedMonthGenitiveNames ICU test suit

* AbbreviatedMonthNames ICU test suit

* MonthGenitive ICU test suit

* refactor CalendarData.iOS.cs
to use more of the shared CalendarData.ICU code

* refactor new DateTiemFormatInfo* API tests

src/libraries/System.Private.CoreLib/src/System/Globalization/CalendarData.Icu.cs

@@ -436,7 +436,12 @@ namespace System.Globalization
 #pragma warning disable CS8500 // takes address of managed type
         private static unsafe bool EnumCalendarInfo(string localeName, CalendarId calendarId, CalendarDataType dataType, IcuEnumCalendarsData* callbackContext)
         {
+#if TARGET_MACCATALYST || TARGET_IOS || TARGET_TVOS
+            callbackContext->Results.AddRange(GetCalendarInfoNative(localeName, calendarId, dataType).Split("||"));
+            return callbackContext->Results.Count > 0;
+#else
             return Interop.Globalization.EnumCalendarInfo(&EnumCalendarInfoCallback, localeName, calendarId, dataType, (IntPtr)callbackContext);
+#endif
         }
 #pragma warning restore CS8500
 

src/libraries/System.Private.CoreLib/src/System/Globalization/CalendarData.iOS.cs

@@ -17,24 +17,15 @@ namespace System.Globalization
 
             sNativeName = GetCalendarInfoNative(localeName, calendarId, CalendarDataType.NativeName);
             sMonthDay = GetCalendarInfoNative(localeName, calendarId, CalendarDataType.MonthDay);
-            saShortDates = GetCalendarInfoNative(localeName, calendarId, CalendarDataType.ShortDates).Split("||");
-            // Handle ShortDatePattern to have "yyyy" year format
-            List<string> shortDatePatternList = new List<string>(saShortDates);
-            for (int i = 0; i < shortDatePatternList.Count; i++)
-            {
-                shortDatePatternList[i] = NormalizeDatePattern(shortDatePatternList[i]);
-            }
-            FixDefaultShortDatePattern(shortDatePatternList);
-            saShortDates = shortDatePatternList.ToArray();
-
-            saLongDates = GetCalendarInfoNative(localeName, calendarId, CalendarDataType.LongDates).Split("||");
-            saYearMonths = GetCalendarInfoNative(localeName, calendarId, CalendarDataType.YearMonths).Split("||");
-            saDayNames = GetCalendarInfoNative(localeName, calendarId, CalendarDataType.DayNames).Split("||");
-            saAbbrevDayNames = GetCalendarInfoNative(localeName, calendarId, CalendarDataType.AbbrevDayNames).Split("||");
-            saSuperShortDayNames = GetCalendarInfoNative(localeName, calendarId, CalendarDataType.SuperShortDayNames).Split("||");
+            EnumDatePatterns(localeName, calendarId, CalendarDataType.ShortDates, out this.saShortDates!);
+            EnumDatePatterns(localeName, calendarId, CalendarDataType.LongDates, out this.saLongDates!);
+            EnumDatePatterns(localeName, calendarId, CalendarDataType.YearMonths, out this.saYearMonths!);
+            EnumCalendarInfo(localeName, calendarId, CalendarDataType.DayNames, out this.saDayNames!);
+            EnumCalendarInfo(localeName, calendarId, CalendarDataType.AbbrevDayNames, out this.saAbbrevDayNames!);
+            EnumCalendarInfo(localeName, calendarId, CalendarDataType.SuperShortDayNames, out this.saSuperShortDayNames!);
 
             string? leapHebrewMonthName = null;
-            saMonthNames = NormalizeMonthArray(GetCalendarInfoNative(localeName, calendarId, CalendarDataType.MonthNames).Split("||"), calendarId, ref leapHebrewMonthName);
+            EnumMonthNames(localeName, calendarId, CalendarDataType.MonthNames, out this.saMonthNames!, ref leapHebrewMonthName);
             if (leapHebrewMonthName != null)
             {
                 Debug.Assert(saMonthNames != null);
@@ -51,12 +42,12 @@ namespace System.Globalization
                 saMonthNames[6] = leapHebrewMonthName;
 
             }
-            saAbbrevMonthNames = NormalizeMonthArray(GetCalendarInfoNative(localeName, calendarId, CalendarDataType.AbbrevMonthNames).Split("||"), calendarId, ref leapHebrewMonthName);
-            saMonthGenitiveNames = NormalizeMonthArray(GetCalendarInfoNative(localeName, calendarId, CalendarDataType.MonthGenitiveNames).Split("||"), calendarId, ref leapHebrewMonthName);
-            saAbbrevMonthGenitiveNames = NormalizeMonthArray(GetCalendarInfoNative(localeName, calendarId, CalendarDataType.AbbrevMonthGenitiveNames).Split("||"), calendarId, ref leapHebrewMonthName);
+            EnumMonthNames(localeName, calendarId, CalendarDataType.AbbrevMonthNames, out this.saAbbrevMonthNames!, ref leapHebrewMonthName);
+            EnumMonthNames(localeName, calendarId, CalendarDataType.MonthGenitiveNames, out this.saMonthGenitiveNames!, ref leapHebrewMonthName);
+            EnumMonthNames(localeName, calendarId, CalendarDataType.AbbrevMonthGenitiveNames, out this.saAbbrevMonthGenitiveNames!, ref leapHebrewMonthName);
 
-            saEraNames = NormalizeEraNames(calendarId, GetCalendarInfoNative(localeName, calendarId, CalendarDataType.EraNames).Split("||"));
-            saAbbrevEraNames = Array.Empty<string>();
+            EnumEraNames(localeName, calendarId, CalendarDataType.EraNames, out this.saEraNames!);
+            EnumEraNames(localeName, calendarId, CalendarDataType.AbbrevEraNames, out this.saAbbrevEraNames!);
 
             return sNativeName != null && saShortDates != null && saLongDates != null && saYearMonths != null &&
                    saDayNames != null && saAbbrevDayNames != null && saSuperShortDayNames != null && saMonthNames != null &&
@@ -64,49 +55,6 @@ namespace System.Globalization
                    saEraNames != null && saAbbrevEraNames != null;
         }
 
-        private static string[] NormalizeEraNames(CalendarId calendarId, string[]? eraNames)
-        {
-            // .NET expects that only the Japanese calendars have more than 1 era.
-            // So for other calendars, only return the latest era.
-            if (calendarId != CalendarId.JAPAN && calendarId != CalendarId.JAPANESELUNISOLAR && eraNames?.Length > 0)
-                return new string[] { eraNames![eraNames.Length - 1] };
-
-            return eraNames ?? Array.Empty<string>();
-        }
-
-        private static string[] NormalizeMonthArray(string[] months, CalendarId calendarId, ref string? leapHebrewMonthName)
-        {
-            if (months.Length == 13)
-                return months;
-
-            string[] normalizedMonths = new string[13];
-            // the month-name arrays are expected to have 13 elements.  If only returns 12, add an
-            // extra empty string to fill the array.
-            if (months.Length == 12)
-            {
-                normalizedMonths[12] = "";
-                months.CopyTo(normalizedMonths, 0);
-                return normalizedMonths;
-            }
-
-            if (months.Length > 13)
-            {
-                Debug.Assert(calendarId == CalendarId.HEBREW && months.Length == 14);
-
-                if (calendarId == CalendarId.HEBREW)
-                {
-                    leapHebrewMonthName = months[13];
-                }
-                for (int i = 0; i < 13; i++)
-                {
-                    normalizedMonths[i] = months[i];
-                }
-                return normalizedMonths;
-            }
-
-            throw new Exception("CalendarData.GetCalendarInfoNative() returned an unexpected number of month names.");
-        }
-
         private static string GetCalendarInfoNative(string localeName, CalendarId calendarId, CalendarDataType calendarDataType)
         {
             Debug.Assert(localeName != null);

src/libraries/System.Runtime/tests/System.Globalization.Tests/DateTimeFormatInfo/DateTimeFormatInfoAbbreviatedDayNames.cs

@@ -28,6 +28,12 @@ namespace System.Globalization.Tests
             yield return new object[] { new string[] { "", "", "", "", "", "", "" } };
         }
 
+        public static IEnumerable<object[]> AbbreviatedDayNames_Get_TestData_ICU()
+        {
+            yield return new object[] { CultureInfo.GetCultureInfo("en-US").DateTimeFormat, new string[] { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" } };
+            yield return new object[] { CultureInfo.GetCultureInfo("fr-FR").DateTimeFormat, new string[] { "dim.", "lun.", "mar.", "mer.", "jeu.", "ven.", "sam." } };
+        }
+
         public static IEnumerable<object[]> AbbreviatedDayNames_Get_TestData_HybridGlobalization()
         {
             // see the comments on the right to check the non-Hybrid result, if it differs
@@ -86,6 +92,13 @@ namespace System.Globalization.Tests
             yield return new object[] { "zh-CN", new string[] { "周日", "周一", "周二", "周三", "周四", "周五", "周六" } };
         }
 
+        [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsIcuGlobalization))]
+        [MemberData(nameof(AbbreviatedDayNames_Get_TestData_ICU))]
+        public void AbbreviatedDayNames_Get_ReturnsExpected_ICU(DateTimeFormatInfo format, string[] expected)
+        {
+            Assert.Equal(expected, format.AbbreviatedDayNames);
+        }
+
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsHybridGlobalizationOnBrowser))]
         [MemberData(nameof(AbbreviatedDayNames_Get_TestData_HybridGlobalization))]
         public void AbbreviatedDayNames_Get_ReturnsExpected_HybridGlobalization(string cultureName, string[] expected)

src/libraries/System.Runtime/tests/System.Globalization.Tests/DateTimeFormatInfo/DateTimeFormatInfoAbbreviatedMonthGenitiveNames.cs

@@ -8,6 +8,11 @@ namespace System.Globalization.Tests
 {
     public class DateTimeFormatInfoAbbreviatedMonthGenitiveNames
     {
+        public static IEnumerable<object[]> AbbreviatedMonthGenitiveNames_Get_TestData_ICU()
+        {
+            yield return new object[] { CultureInfo.GetCultureInfo("en-US").DateTimeFormat, new string[] { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", "" } };
+            yield return new object[] { CultureInfo.GetCultureInfo("fr-FR").DateTimeFormat, new string[] { "janv.", "févr.", "mars", "avr.", "mai", "juin", "juil.", "août", "sept.", "oct.", "nov.", "déc.", "" } };
+        }
         public static IEnumerable<object[]> AbbreviatedMonthGenitiveNames_Get_TestData_HybridGlobalization()
         {
             // see the comments on the right to check the non-Hybrid result, if it differs
@@ -209,6 +214,13 @@ namespace System.Globalization.Tests
             yield return new object[] { "zh-TW", new string[] { "1月", "2月", "3月", "4月", "5月", "6月", "7月", "8月", "9月", "10月", "11月", "12月", "" } };
         }
 
+        [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsIcuGlobalization))]
+        [MemberData(nameof(AbbreviatedMonthGenitiveNames_Get_TestData_ICU))]
+        public void AbbreviatedMonthGenitiveNames_Get_ReturnsExpected_ICU(DateTimeFormatInfo format, string[] expected)
+        {
+            Assert.Equal(expected, format.AbbreviatedMonthGenitiveNames);
+        }
+
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsHybridGlobalizationOnBrowser))]
         [MemberData(nameof(AbbreviatedMonthGenitiveNames_Get_TestData_HybridGlobalization))]
         public void AbbreviatedMonthGenitiveNames_Get_ReturnsExpected_HybridGlobalization(string cultureName, string[] expected)

src/libraries/System.Runtime/tests/System.Globalization.Tests/DateTimeFormatInfo/DateTimeFormatInfoAbbreviatedMonthNames.cs

@@ -28,6 +28,13 @@ namespace System.Globalization.Tests
             yield return new object[] { new string[] { "", "", "", "", "", "", "", "", "", "", "", "", "" } };
         }
 
+        public static IEnumerable<object[]> AbbreviatedMonthNames_Get_TestData_ICU()
+        {
+            yield return new object[] { CultureInfo.GetCultureInfo("en-US").DateTimeFormat, new string[] { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", "" } };
+            yield return new object[] { CultureInfo.GetCultureInfo("fr-FR").DateTimeFormat, new string[] { "janv.", "févr.", "mars", "avr.", "mai", "juin", "juil.", "août", "sept.", "oct.", "nov.", "déc.", "" } };
+        }
+
+
         public static IEnumerable<object[]> AbbreviatedMonthNames_Get_TestData_HybridGlobalization()
         {
             // see the comments on the right to check the non-Hybrid result, if it differs
@@ -232,6 +239,13 @@ namespace System.Globalization.Tests
             yield return new object[] { "zh-TW", new string[] { "1月", "2月", "3月", "4月", "5月", "6月", "7月", "8月", "9月", "10月", "11月", "12月", "" } };
         }
 
+        [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsIcuGlobalization))]
+        [MemberData(nameof(AbbreviatedMonthNames_Get_TestData_ICU))]
+        public void AbbreviatedMonthNames_Get_ReturnsExpected_ICU(DateTimeFormatInfo format, string[] expected)
+        {
+            Assert.Equal(expected, format.AbbreviatedMonthNames);
+        }
+
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsHybridGlobalizationOnBrowser))]
         [MemberData(nameof(AbbreviatedMonthNames_Get_TestData_HybridGlobalization))]
         public void AbbreviatedMonthNames_Get_ReturnsExpected_HybridGlobalization(string cultureName, string[] expected)

src/libraries/System.Runtime/tests/System.Globalization.Tests/DateTimeFormatInfo/DateTimeFormatInfoDayNames.cs

@@ -28,6 +28,12 @@ namespace System.Globalization.Tests
             yield return new object[] { new string[] { "", "", "", "", "", "", "" } };
         }
 
+        public static IEnumerable<object[]> DayNames_Get_TestData_ICU()
+        {
+            yield return new object[] { CultureInfo.GetCultureInfo("en-US").DateTimeFormat, new string[] { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" } };
+            yield return new object[] { CultureInfo.GetCultureInfo("fr-FR").DateTimeFormat, new string[] { "dimanche", "lundi", "mardi", "mercredi", "jeudi", "vendredi", "samedi" } };
+        }
+
         public static IEnumerable<object[]> DayNames_Get_TestData_HybridGlobalization()
         {
             yield return new object[] { "ar-SA", new string[] { "الأحد", "الاثنين", "الثلاثاء", "الأربعاء", "الخميس", "الجمعة", "السبت" } };
@@ -78,6 +84,13 @@ namespace System.Globalization.Tests
             yield return new object[] { "zh-TW", new string[] { "星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六" } };
         }
 
+        [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsIcuGlobalization))]
+        [MemberData(nameof(DayNames_Get_TestData_ICU))]
+        public void DayNames_Get_ReturnsExpected_ICU(DateTimeFormatInfo format, string[] expected)
+        {
+            Assert.Equal(expected, format.DayNames);
+        }
+
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsHybridGlobalizationOnBrowser))]
         [MemberData(nameof(DayNames_Get_TestData_HybridGlobalization))]
         public void DayNames_Get_ReturnsExpected_HybridGlobalization(string cultureName, string[] expected)

src/libraries/System.Runtime/tests/System.Globalization.Tests/DateTimeFormatInfo/DateTimeFormatInfoLongDatePattern.cs

@@ -25,6 +25,12 @@ namespace System.Globalization.Tests
             yield return new object[] { "dddd, dd MMMM yyyy" };
         }
 
+        public static IEnumerable<object[]> LongDatePattern_Get_TestData_ICU()
+        {
+            yield return new object[] { CultureInfo.GetCultureInfo("en-US").DateTimeFormat, "dddd, MMMM d, yyyy" };
+            yield return new object[] { CultureInfo.GetCultureInfo("fr-FR").DateTimeFormat,  "dddd d MMMM yyyy" };
+        }
+
         public static IEnumerable<object[]> LongDatePattern_Get_TestData_HybridGlobalization()
         {
             // see the comments on the right to check the non-Hybrid result, if it differs
@@ -218,6 +224,13 @@ namespace System.Globalization.Tests
             yield return new object[] {"zh-TW", "yyyy年M月d日 dddd" };
         }
 
+        [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsIcuGlobalization))]
+        [MemberData(nameof(LongDatePattern_Get_TestData_ICU))]
+        public void LongDatePattern_Get_ReturnsExpected_ICU(DateTimeFormatInfo format, string expected)
+        {
+            Assert.Equal(expected, format.LongDatePattern);
+        }
+
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsHybridGlobalizationOnBrowser))]
         [MemberData(nameof(LongDatePattern_Get_TestData_HybridGlobalization))]
         public void LongDatePattern_Get_ReturnsExpected_HybridGlobalization(string cultureName, string expected)

src/libraries/System.Runtime/tests/System.Globalization.Tests/DateTimeFormatInfo/DateTimeFormatInfoMonthDayPattern.cs

@@ -26,6 +26,12 @@ namespace System.Globalization.Tests
             yield return new object[] { "m" };
         }
 
+        public static IEnumerable<object[]> MonthDayPattern_Get_TestData_ICU()
+        {
+            yield return new object[] { CultureInfo.GetCultureInfo("en-US").DateTimeFormat, "MMMM d" };
+            yield return new object[] { CultureInfo.GetCultureInfo("fr-FR").DateTimeFormat,  "d MMMM" };
+        }
+
         public static IEnumerable<object[]> MonthDayPattern_Get_TestData_HybridGlobalization()
         {
             // see the comments on the right to check the non-Hybrid result, if it differs
@@ -149,7 +155,6 @@ namespace System.Globalization.Tests
             yield return new object[] { new CultureInfo("en-ZA").DateTimeFormat, "d MMMM" };
             yield return new object[] { new CultureInfo("en-ZM").DateTimeFormat, "d MMMM" };
             yield return new object[] { new CultureInfo("en-ZW").DateTimeFormat, "d MMMM" };
-            yield return new object[] { new CultureInfo("en-US").DateTimeFormat, "MMMM d" };
             yield return new object[] { new CultureInfo("es-419").DateTimeFormat, "d de MMMM" }; // d 'de' MMMM
             yield return new object[] { new CultureInfo("es-ES").DateTimeFormat, "d de MMMM" }; // d 'de' MMMM
             yield return new object[] { new CultureInfo("es-MX").DateTimeFormat, "d de MMMM" }; // d 'de' MMMM
@@ -216,6 +221,13 @@ namespace System.Globalization.Tests
             yield return new object[] { new CultureInfo("zh-HK").DateTimeFormat, "M月d日" };
             yield return new object[] { new CultureInfo("zh-TW").DateTimeFormat, "M月d日" };
         }
+        
+        [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsIcuGlobalization))]
+        [MemberData(nameof(MonthDayPattern_Get_TestData_ICU))]
+        public void MonthDayPattern_Get_ReturnsExpected_ICU(DateTimeFormatInfo format, string expected)
+        {
+            Assert.Equal(expected, format.MonthDayPattern);
+        }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsHybridGlobalizationOnBrowser))]
         [MemberData(nameof(MonthDayPattern_Get_TestData_HybridGlobalization))]

src/libraries/System.Runtime/tests/System.Globalization.Tests/DateTimeFormatInfo/DateTimeFormatInfoMonthGenitiveNames.cs

@@ -13,7 +13,7 @@ namespace System.Globalization.Tests
             yield return new object[] { DateTimeFormatInfo.InvariantInfo, new string[] { "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December", "" } };
             yield return new object[]
             {
-                new CultureInfo("ru-RU").DateTimeFormat,
+                CultureInfo.GetCultureInfo("ru-RU").DateTimeFormat,
                 new string[]
                 {
                     "\u044F\u043D\u0432\u0430\u0440\u044F",
@@ -31,6 +31,11 @@ namespace System.Globalization.Tests
                     ""
                 }
             };
+            if (PlatformDetection.IsIcuGlobalization)
+            {
+                yield return new object[] { CultureInfo.GetCultureInfo("en-US").DateTimeFormat, new string[] { "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December", "" } };
+                yield return new object[] { CultureInfo.GetCultureInfo("fr-FR").DateTimeFormat, new string[] { "janvier", "février", "mars", "avril", "mai", "juin", "juillet", "août", "septembre", "octobre", "novembre", "décembre", "" } };
+            }
             if (PlatformDetection.IsHybridGlobalizationOnBrowser)
             {
                 // see the comments on the right to check the non-Hybrid result, if it differs

src/libraries/System.Runtime/tests/System.Globalization.Tests/DateTimeFormatInfo/DateTimeFormatInfoMonthNames.cs

@@ -28,6 +28,12 @@ namespace System.Globalization.Tests
             yield return new object[] { new string[] { "", "", "", "", "", "", "", "", "", "", "", "", "" } };
         }
 
+        public static IEnumerable<object[]> MonthNames_Get_TestData_ICU()
+        {
+            yield return new object[] { CultureInfo.GetCultureInfo("en-US").DateTimeFormat, new string[] { "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December", "" } };
+            yield return new object[] { CultureInfo.GetCultureInfo("fr-FR").DateTimeFormat, new string[] { "janvier", "février", "mars", "avril", "mai", "juin", "juillet", "août", "septembre", "octobre", "novembre", "décembre", "" } };
+        }
+
         public static IEnumerable<object[]> MonthNames_Get_TestData_HybridGlobalization()
         {
             // see the comments on the right to check the non-Hybrid result, if it differs
@@ -227,6 +233,13 @@ namespace System.Globalization.Tests
             yield return new object[] { new CultureInfo("zh-TW").DateTimeFormat, new string[] { "1月", "2月", "3月", "4月", "5月", "6月", "7月", "8月", "9月", "10月", "11月", "12月", "" } };
         }
 
+        [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsIcuGlobalization))]
+        [MemberData(nameof(MonthNames_Get_TestData_ICU))]
+        public void MonthNames_Get_ReturnsExpected_ICU(DateTimeFormatInfo format, string[] expected)
+        {
+            Assert.Equal(expected, format.MonthNames);
+        }
+
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsHybridGlobalizationOnBrowser))]
         [MemberData(nameof(MonthNames_Get_TestData_HybridGlobalization))]
         public void MonthNames_Get_ReturnsExpected(DateTimeFormatInfo format, string[] expected)

src/libraries/System.Runtime/tests/System.Globalization.Tests/DateTimeFormatInfo/DateTimeFormatInfoShortDatePattern.cs

@@ -8,12 +8,12 @@ namespace System.Globalization.Tests
 {
     public class DateTimeFormatInfoShortDatePattern
     {
-        public static IEnumerable<object[]> ShortDatePattern_Get_TestData()
+        public static IEnumerable<object[]> ShortDatePattern_Get_TestData_ICU()
         {
-            yield return new object[] { DateTimeFormatInfo.InvariantInfo, "MM/dd/yyyy", "invariant" };
-            yield return new object[] { new CultureInfo("en-US").DateTimeFormat, "M/d/yyyy", "en-US" };
-            yield return new object[] { new CultureInfo("fr-FR").DateTimeFormat, "dd/MM/yyyy", "fr-FR" };
+            yield return new object[] { CultureInfo.GetCultureInfo("en-US").DateTimeFormat, "M/d/yyyy" };
+            yield return new object[] { CultureInfo.GetCultureInfo("fr-FR").DateTimeFormat, "dd/MM/yyyy" };
         }
+
         public static IEnumerable<object[]> ShortDatePattern_Get_TestData_HybridGlobalization()
         {
             // see the comments on the right to check the non-Hybrid result, if it differs
@@ -205,11 +205,11 @@ namespace System.Globalization.Tests
             yield return new object[] { "zh-TW", "yyyy/M/d" };
         }
 
-        [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsHybridGlobalizationOnApplePlatform))]
-        [MemberData(nameof(ShortDatePattern_Get_TestData))]
-        public void ShortDatePattern_Get_ReturnsExpected(DateTimeFormatInfo format, string expected, string cultureName)
+        [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsIcuGlobalization))]
+        [MemberData(nameof(ShortDatePattern_Get_TestData_ICU))]
+        public void ShortDatePattern_Get_ReturnsExpected_ICU(DateTimeFormatInfo format, string expected)
         {
-            Assert.True(expected == format.ShortDatePattern, $"Failed for culture: {cultureName}. Expected: {expected}, Actual: {format.ShortDatePattern}");
+            Assert.Equal(expected, format.ShortDatePattern);
         }
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsHybridGlobalizationOnBrowser))]

src/libraries/System.Runtime/tests/System.Globalization.Tests/Hybrid/AppleHybrid.Tests.csproj

@@ -0,0 +1,37 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFrameworks>$(NetCoreAppCurrent)-ios;$(NetCoreAppCurrent)-tvos;$(NetCoreAppCurrent)-maccatalyst</TargetFrameworks>
+    <TestRuntime>true</TestRuntime>
+    <HybridGlobalization>true</HybridGlobalization>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <IncludeRemoteExecutor>true</IncludeRemoteExecutor>
+    <UnicodeUcdVersion>15.0</UnicodeUcdVersion>
+  </PropertyGroup>
+  <ItemGroup>
+    <RdXmlFile Include="..\default.rd.xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="..\AssemblyInfo.cs" />
+    <Compile Include="..\IcuTests.cs" />
+    <Compile Include="..\DateTimeFormatInfo\DateTimeFormatInfoLongDatePattern.cs" />
+    <Compile Include="..\DateTimeFormatInfo\DateTimeFormatInfoShortDatePattern.cs" />
+    <Compile Include="..\DateTimeFormatInfo\DateTimeFormatInfoMonthDayPattern.cs" />
+    <!-- Helpers -->
+    <Compile Include="$(CommonTestPath)System\RandomDataGenerator.cs"
+             Link="..\Common\System\RandomDataGenerator.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="System.Private.Runtime.UnicodeData" Version="$(SystemPrivateRuntimeUnicodeDataVersion)" ExcludeAssets="contentFiles" GeneratePathProperty="true" />
+    <EmbeddedResource Include="$(PkgSystem_Private_Runtime_UnicodeData)\contentFiles\any\any\$(UnicodeUcdVersion).0\ucd\UnicodeData.txt">
+      <Link>CharUnicodeInfo\UnicodeData.$(UnicodeUcdVersion).txt</Link>
+      <LogicalName>UnicodeData.txt</LogicalName>
+    </EmbeddedResource>
+    <EmbeddedResource Include="$(PkgSystem_Private_Runtime_UnicodeData)\contentFiles\any\any\$(UnicodeUcdVersion).0\ucd\auxiliary\GraphemeBreakTest.txt">
+      <Link>CharUnicodeInfo\GraphemeBreakTest-$(UnicodeUcdVersion).0.txt</Link>
+      <LogicalName>GraphemeBreakTest.txt</LogicalName>
+    </EmbeddedResource>
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="$(CommonTestPath)TestUtilities.Unicode\TestUtilities.Unicode.csproj" />
+  </ItemGroup>
+</Project>

src/native/libs/System.Globalization.Native/pal_calendarData.m

@@ -130,7 +130,7 @@ const char* GlobalizationNative_GetCalendarInfoNative(const char* localeName, Ca
                 NSString *longFormatString = [dateFormat dateFormat];
                 [dateFormat setDateStyle:NSDateFormatterFullStyle];
                 NSString *fullFormatString = [dateFormat dateFormat];
-                result = @[longFormatString, fullFormatString];
+                result = @[fullFormatString, longFormatString];
                 break;
             }
             case CalendarData_DayNames: