[Test Only] Fix Idn tests

src/libraries/System.Globalization.Extensions/tests/IdnMapping/Data/ConformanceIdnaTestResult.cs

@@ -27,22 +27,30 @@ public class ConformanceIdnaTestResult
         /// </summary>
         public string Value { get; private set; }
 
+        public string? Source { get; private set; }
+
         public IdnaTestResultType ResultType { get; private set; }
 
         public string StatusValue { get; private set; }
 
         public ConformanceIdnaTestResult(string entry, string fallbackValue, IdnaTestResultType resultType = IdnaTestResultType.ToAscii)
-            : this(entry, fallbackValue, null, null, useValueForStatus: true, resultType)
+            : this(entry, fallbackValue, null, null, useValueForStatus: true, resultType, null)
         {
         }
 
         public ConformanceIdnaTestResult(string entry, string fallbackValue, string statusValue, string statusFallbackValue, IdnaTestResultType resultType = IdnaTestResultType.ToAscii)
-            : this(entry, fallbackValue, statusValue, statusFallbackValue, useValueForStatus: false, resultType)
+            : this(entry, fallbackValue, statusValue, statusFallbackValue, useValueForStatus: false, resultType, null)
+        {
+        }
+
+        public ConformanceIdnaTestResult(string entry, string fallbackValue, string statusValue, string statusFallbackValue, string? source, IdnaTestResultType resultType = IdnaTestResultType.ToAscii)
+            : this(entry, fallbackValue, statusValue, statusFallbackValue, useValueForStatus: false, resultType, source)
         {
         }
 
-        private ConformanceIdnaTestResult(string entry, string fallbackValue, string statusValue, string statusFallbackValue, bool useValueForStatus, IdnaTestResultType resultType)
+        private ConformanceIdnaTestResult(string entry, string fallbackValue, string statusValue, string statusFallbackValue, bool useValueForStatus, IdnaTestResultType resultType, string? source)
         {
+            Source = source;
             ResultType = resultType;
             SetValue(string.IsNullOrEmpty(entry.Trim()) ? fallbackValue : entry);
             SetSuccess(useValueForStatus ?
@@ -81,11 +89,120 @@ private void SetSuccess(string statusValue)
             }
         }
 
+        // Fullwidth Full Stop, Ideographic Full Stop, and Halfwidth Ideographic Full Stop
+        private static char[] AllDots = ['.', '\uFF0E', '\u3002', '\uFF61'];
+
+        private const char SoftHyphen = '\u00AD';
+
+        private bool IsIgnorableA4_2Rule()
+        {
+            if (Source is null)
+            {
+                return false;
+            }
+
+            // Check the label lengths for the ASCII
+            int lastIndex = 0;
+            int index = Value.IndexOfAny(AllDots);
+            while (index >= 0)
+            {
+                if (index - lastIndex > 63) // 63 max label length
+                {
+                    return false;
+                }
+
+                lastIndex = index + 1;
+                index = Value.IndexOfAny(AllDots, lastIndex);
+            }
+
+            if (Value.Length - lastIndex > 63)
+            {
+                return false;
+            }
+
+            // Remove Hyphen as it is ignored
+            if (Source.IndexOf(SoftHyphen) >= 0)
+            {
+                Span<char> span = stackalloc char[Source.Length];
+                int spanIndex = 0;
+
+                for (int i = 0; i < Source.Length; i++)
+                {
+                    if (Source[i] != SoftHyphen)
+                    {
+                        span[spanIndex++] = Source[i];
+                    }
+                }
+
+                Source = span.Slice(0, spanIndex).ToString();
+            }
+
+            // Check the label lengths for the Source
+            lastIndex = 0;
+            index = Source.IndexOfAny(AllDots);
+            while (index >= 0)
+            {
+                if (index - lastIndex > 63) // 63 max label length
+                {
+                    return false;
+                }
+
+                lastIndex = index + 1;
+                index = Source.IndexOfAny(AllDots, lastIndex);
+            }
+
+            if (Source.Length - lastIndex > 63)
+            {
+                return false;
+            }
+
+            if (Source[0] is '.') // Leading dot
+            {
+                return false;
+            }
+
+            for (int i = 0; i < Source.Length - 1; i++)
+            {
+                // Consequence dots
+                if ((Source[i] is '.' or '\uFF0E' or '\u3002' or '\uFF61') && (Source[i + 1] is '.' or '\uFF0E' or '\u3002' or '\uFF61'))
+                {
+                    return false;
+                }
+
+                // Check Historical Ranges
+                if (Source[i] >= 0x2C00 && Source[i] <= 0x2C5F) // Glagolitic (U+2C00–U+2C5F)
+                    return false;
+
+                switch (Source[i])
+                {
+                    case '\uD800':
+                        if (Source[i + 1] >= 0xDFA0 && Source[i + 1] <= 0xDFDF) return false; // Old Persian (U+103A0–U+103DF)
+                        if (Source[i + 1] >= 0xDF30 && Source[i + 1] <= 0xDF4F) return false; // Gothic (U+10330–U+1034F)
+                        if (Source[i + 1] >= 0xDC00 && Source[i + 1] <= 0xDC7F) return false; // Linear B (U+10000–U+1007F)
+                        break;
+                    case '\uD802':
+                        if (Source[i + 1] >= 0xDD00  && Source[i + 1] <= 0xDD1F) return false; // Phoenician (U+10900–U+1091F)
+                        break;
+                    case '\uD803':
+                        if (Source[i + 1] >= 0xDEA0 && Source[i + 1] <= 0xDEAF) return false; // Elymaic (U+10EA0–U+10EAF)
+                        break;
+                    case '\uD808':
+                        if (Source[i + 1] >= 0xDC00 && Source[i + 1] <= 0xDFFF) return false; // Cuneiform (U+12000–U+123FF)
+                        break;
+                    case '\uD838':
+                        if (Source[i + 1] >= 0xDC00 && Source[i + 1] <= 0xDCDF) return false; // Indic Siyaq Numbers (U+1E800–U+1E8DF)
+                        break;
+                }
+            }
+
+            return true;
+        }
+
         private bool IsIgnoredError(string statusCode)
         {
             // We don't validate for BIDI rule so we can ignore BIDI codes
             // If we're validating ToAscii we ignore rule V2 (UIDNA_ERROR_HYPHEN_3_4) for compatibility with windows.
-            return statusCode.StartsWith('B') || (ResultType == IdnaTestResultType.ToAscii && statusCode == "V2");
+            return statusCode.StartsWith('B') || (ResultType == IdnaTestResultType.ToAscii && statusCode == "V2") || (statusCode.StartsWith("A4_2") && IsIgnorableA4_2Rule());
         }
     }
 }

src/libraries/System.Globalization.Extensions/tests/IdnMapping/Data/ConformanceIdnaUnicodeTestResult.cs

@@ -13,6 +13,12 @@ public ConformanceIdnaUnicodeTestResult(string entry, string fallbackValue, bool
             ValidDomainName = validDomainName;
         }
 
+        public ConformanceIdnaUnicodeTestResult(string entry, string fallbackValue, string statusValue, string statusFallbackValue, string? source, bool validDomainName = true)
+            : base(entry, fallbackValue, statusValue, statusFallbackValue, source, IdnaTestResultType.ToUnicode)
+        {
+            ValidDomainName = validDomainName;
+        }
+
         public ConformanceIdnaUnicodeTestResult(string entry, string fallbackValue, string statusValue, string statusFallbackValue, bool validDomainName = true)
             : base(entry, fallbackValue, statusValue, statusFallbackValue, IdnaTestResultType.ToUnicode)
         {

src/libraries/System.Globalization.Extensions/tests/IdnMapping/Data/Factory.cs

@@ -26,8 +26,12 @@ private static string RemoveComment(string line)
         private static Stream GetIdnaTestTxt()
         {
             string fileName = null;
-            if (PlatformDetection.ICUVersion >= new Version(74, 0))
+            if (PlatformDetection.ICUVersion >= new Version(76, 0))
+                fileName = "IdnaTest_16.txt";
+            else if (PlatformDetection.ICUVersion >= new Version(72, 1, 0, 4))
                 fileName = "IdnaTest_15_1.txt";
+            else if (PlatformDetection.ICUVersion >= new Version(72, 0))
+                fileName = "IdnaTest_15_0.txt";
             else if (PlatformDetection.ICUVersion >= new Version(66, 0))
                 fileName = "IdnaTest_13.txt";
             else if (PlatformDetection.IsWindows7)
@@ -63,8 +67,12 @@ private static IEnumerable<IConformanceIdnaTest> ParseFile(Stream stream, Func<s
 
         private static IConformanceIdnaTest GetConformanceIdnaTest(string line, int lineCount)
         {
-            if (PlatformDetection.ICUVersion >= new Version(74, 0))
+            if (PlatformDetection.ICUVersion >= new Version(76, 0))
+                return new Unicode_16_0_IdnaTest(line, lineCount);
+            else if (PlatformDetection.ICUVersion >= new Version(72, 1, 0, 4))
                 return new Unicode_15_1_IdnaTest(line, lineCount);
+            else if (PlatformDetection.ICUVersion >= new Version(72, 0))
+                return new Unicode_15_0_IdnaTest(line, lineCount);
             else if (PlatformDetection.ICUVersion >= new Version(66, 0))
                 return new Unicode_13_0_IdnaTest(line, lineCount);
             else if (PlatformDetection.IsWindows7)