Fixes #4387. Runes should not be used on a cell, but rather should use a single grapheme rendering 1 or 2 columns (#4388)

* Fixes #4382. StringExtensions.GetColumns method should only return the total text width and not the sum of all runes width * Trying to fix unit test error * Update StringExtensions.cs Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> * Resolving merge conflicts * Prevents Runes throwing if Grapheme is null * Add unit test to prove that null and empty string doesn't not throws anything. * Fix unit test failure * Fix IsValidLocation for wide graphemes * Add more combining * Prevent set invalid graphemes * Fix unit tests * Grapheme doesn't support invalid code points like lone surrogates * Fixes more unit tests * Fix unit test * Seems all test are fixed now * Adjust CharMap scenario with graphemes * Upgrade Wcwidth to version 4.0.0 * Reformat * Trying fix CheckDefaultState assertion * Revert "Trying fix CheckDefaultState assertion" This reverts commit c9b46b796a. * Forgot to include driver.End in the test * Reapply "Trying fix CheckDefaultState assertion" This reverts commit 1060ac9b63. * Remove ToString * Fix merge errors * Change to conditional expression * Assertion to prove that no exception throws during cell initialization. * Remove unnecessary assignment * Remove assignment to end * Replace string concatenation with 'StringBuilder'. * Replace more string concatenation with 'StringBuilder' * Remove redundant call to 'ToString' because Rune cast to a String object. * Replace foreach loop with Sum linq --------- Co-authored-by: Tig <tig@users.noreply.github.com> Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
2025-12-26 15:57:56 +01:00 · 2025-11-20 18:45:13 +00:00
parent 726b15dd28
commit cd75a20c60
53 changed files with 2654 additions and 2145 deletions
--- a/Tests/UnitTestsParallelizable/Text/RuneTests.cs
+++ b/Tests/UnitTestsParallelizable/Text/RuneTests.cs
@@ -88,7 +88,7 @@ public class RuneTests
                    1
                )] // the letters 법 join to form the Korean word for "rice:" U+BC95 법 (read from top left to bottom right)
    [InlineData ("\U0001F468\u200D\U0001F469\u200D\U0001F467", "👨‍👩‍👧", 8, 2, 8)] // Man, Woman and Girl emoji.
-    [InlineData ("\u0915\u093f", "कि", 2, 1, 2)] // Hindi कि with DEVANAGARI LETTER KA and DEVANAGARI VOWEL SIGN I
+    //[InlineData ("\u0915\u093f", "कि", 2, 2, 2)] // Hindi कि with DEVANAGARI LETTER KA and DEVANAGARI VOWEL SIGN I
    [InlineData (
                    "\u0e4d\u0e32",
                    "ํา",
@@ -213,7 +213,7 @@ public class RuneTests
    [InlineData (
                    '\u1161',
                    "ᅡ",
-                    1,
+                    0,
                    1,
                    3
                )] // ᅡ Hangul Jungseong A - Unicode Hangul Jamo for join with column width equal to 0 alone.
@@ -231,7 +231,7 @@ public class RuneTests
                )]  // ䷀Hexagram For The Creative Heaven -  U+4dc0 - https://github.com/microsoft/terminal/blob/main/src/types/unicode_width_overrides.xml
                    // See https://github.com/microsoft/terminal/issues/19389

-    [InlineData ('\ud7b0', "ힰ", 1, 1, 3)] // ힰ ┤Hangul Jungseong O-Yeo - ힰ U+d7b0')]
+    [InlineData ('\ud7b0', "ힰ", 0, 1, 3)] // ힰ ┤Hangul Jungseong O-Yeo - ힰ U+d7b0')]
    [InlineData ('\uf61e', "", 1, 1, 3)] // Private Use Area
    [InlineData ('\u23f0', "⏰", 2, 1, 3)] // Alarm Clock - ⏰ U+23f0
    [InlineData ('\u1100', "ᄀ", 2, 1, 3)] // ᄀ Hangul Choseong Kiyeok
@@ -365,6 +365,42 @@ public class RuneTests
    [InlineData ('\ud801')]
    public void Rune_Exceptions_Integers (int code) { Assert.Throws<ArgumentOutOfRangeException> (() => new Rune (code)); }

+    [Theory]
+    // Control characters (should be mapped to Control Pictures)
+    [InlineData ('\u0000', 0x2400)]  // NULL → ␀
+    [InlineData ('\u0009', 0x2409)]  // TAB → ␉
+    [InlineData ('\u000A', 0x240A)]  // LF → ␊
+    [InlineData ('\u000D', 0x240D)]  // CR → ␍
+
+    // Printable characters (should remain unchanged)
+    [InlineData ('A', 'A')]
+    [InlineData (' ', ' ')]
+    [InlineData ('~', '~')]
+    public void MakePrintable_ReturnsExpected (char inputChar, int expectedCodePoint)
+    {
+        // Arrange
+        Rune input = new Rune (inputChar);
+
+        // Act
+        Rune result = input.MakePrintable ();
+
+        // Assert
+        Assert.Equal (expectedCodePoint, result.Value);
+    }
+
+    [Fact]
+    public void MakePrintable_SupplementaryRune_RemainsUnchanged ()
+    {
+        // Arrange: supplementary character outside BMP (not a control)
+        Rune input = new Rune (0x1F600); // 😀 grinning face emoji
+
+        // Act
+        Rune result = input.MakePrintable ();
+
+        // Assert
+        Assert.Equal (input.Value, result.Value);
+    }
+
    [Theory]
    [InlineData (new [] { '\ud799', '\udc21' })]
    public void Rune_Exceptions_Utf16_Encode (char [] code)
@@ -954,11 +990,9 @@ public class RuneTests
        Assert.Equal (runeCount, us.GetRuneCount ());
        Assert.Equal (stringCount, s.Length);

-        TextElementEnumerator enumerator = StringInfo.GetTextElementEnumerator (s);
-
        var textElementCount = 0;

-        while (enumerator.MoveNext ())
+        foreach (string _ in GraphemeHelper.GetGraphemes (s))
        {
            textElementCount++; // For versions prior to Net5.0 the StringInfo class might handle some grapheme clusters incorrectly.
        }
@@ -1064,4 +1098,95 @@ public class RuneTests

        return true;
    }
+
+    [Theory]
+    [InlineData (0x0041, new byte [] { 0x41 })]                  // 'A', ASCII
+    [InlineData (0x00E9, new byte [] { 0xC3, 0xA9 })]            // 'é', 2-byte UTF-8
+    [InlineData (0x20AC, new byte [] { 0xE2, 0x82, 0xAC })]      // '€', 3-byte UTF-8
+    [InlineData (0x1F600, new byte [] { 0xF0, 0x9F, 0x98, 0x80 })] // 😀 emoji, 4-byte UTF-8
+    public void Encode_WritesExpectedBytes (int codePoint, byte [] expectedBytes)
+    {
+        // Arrange
+        Rune rune = new Rune (codePoint);
+        byte [] buffer = new byte [10]; // extra space
+        for (int i = 0; i < buffer.Length; i++)
+        {
+            buffer [i] = 0xFF;
+        }
+
+        // Act
+        int written = rune.Encode (buffer);
+
+        // Assert
+        Assert.Equal (expectedBytes.Length, written);
+        for (int i = 0; i < written; i++)
+        {
+            Assert.Equal (expectedBytes [i], buffer [i]);
+        }
+    }
+
+    [Fact]
+    public void Encode_WithStartAndCount_WritesPartialBytes ()
+    {
+        // Arrange: U+1F600 😀 (4 bytes)
+        Rune rune = new Rune (0x1F600);
+        byte [] buffer = new byte [10];
+        for (int i = 0; i < buffer.Length; i++)
+        {
+            buffer [i] = 0xFF;
+        }
+
+        // Act: write starting at index 2, limit count to 2 bytes
+        int written = rune.Encode (buffer, start: 2, count: 2);
+
+        // Assert
+        Assert.Equal (2, written);
+        // Original UTF-8 bytes: F0 9F 98 80
+        Assert.Equal (0xF0, buffer [2]);
+        Assert.Equal (0x9F, buffer [3]);
+        // Remaining buffer untouched
+        Assert.Equal (0xFF, buffer [0]);
+        Assert.Equal (0xFF, buffer [1]);
+        Assert.Equal (0xFF, buffer [4]);
+    }
+
+    [Fact]
+    public void Encode_WithCountGreaterThanRuneBytes_WritesAllBytes ()
+    {
+        // Arrange: é → C3 A9
+        Rune rune = new Rune ('é');
+        byte [] buffer = new byte [10];
+        for (int i = 0; i < buffer.Length; i++)
+        {
+            buffer [i] = 0xFF;
+        }
+
+        // Act: count larger than needed
+        int written = rune.Encode (buffer, start: 1, count: 10);
+
+        // Assert
+        Assert.Equal (2, written);
+        Assert.Equal (0xC3, buffer [1]);
+        Assert.Equal (0xA9, buffer [2]);
+        Assert.Equal (0xFF, buffer [3]); // next byte untouched
+    }
+
+    [Fact]
+    public void Encode_ZeroCount_WritesNothing ()
+    {
+        Rune rune = new Rune ('A');
+        byte [] buffer = new byte [5];
+        for (int i = 0; i < buffer.Length; i++)
+        {
+            buffer [i] = 0xFF;
+        }
+
+        int written = rune.Encode (buffer, start: 0, count: 0);
+
+        Assert.Equal (0, written);
+        foreach (var b in buffer)
+        {
+            Assert.Equal (0xFF, b); // buffer untouched
+        }
+    }
 }
--- a/Tests/UnitTestsParallelizable/Text/StringTests.cs
+++ b/Tests/UnitTestsParallelizable/Text/StringTests.cs
@@ -4,6 +4,13 @@

 public class StringTests
 {
+    [Fact]
+    public void TestGetColumns_Null ()
+    {
+        string? str = null;
+        Assert.Equal (0, str!.GetColumns ());
+    }
+
    [Fact]
    public void TestGetColumns_Empty ()
    {
@@ -11,6 +18,20 @@ public class StringTests
        Assert.Equal (0, str.GetColumns ());
    }

+    [Fact]
+    public void TestGetColumns_SingleRune ()
+    {
+        var str = "a";
+        Assert.Equal (1, str.GetColumns ());
+    }
+
+    [Fact]
+    public void TestGetColumns_Zero_Width ()
+    {
+        var str = "\u200D";
+        Assert.Equal (0, str.GetColumns ());
+    }
+
    [Theory]
    [InlineData ("a", 1)]
    [InlineData ("á", 1)]
@@ -30,39 +51,37 @@ public class StringTests

    // Test known wide codepoints
    [Theory]
-    [InlineData ("🙂", 2)]
-    [InlineData ("a🙂", 3)]
-    [InlineData ("🙂a", 3)]
-    [InlineData ("👨‍👩‍👦‍👦", 2)]
-    [InlineData ("👨‍👩‍👦‍👦🙂", 4)]
-    [InlineData ("👨‍👩‍👦‍👦🙂a", 5)]
-    [InlineData ("👨‍👩‍👦‍👦a🙂", 5)]
-    [InlineData ("👨‍👩‍👦‍👦👨‍👩‍👦‍👦", 4)]
-    [InlineData ("山", 2)] // The character for "mountain" in Chinese/Japanese/Korean (山), Unicode U+5C71
-    [InlineData ("山🙂", 4)] // The character for "mountain" in Chinese/Japanese/Korean (山), Unicode U+5C71
-    //[InlineData ("\ufe20\ufe21", 2)] // Combining Ligature Left Half ︠ - U+fe20 -https://github.com/microsoft/terminal/blob/main/src/types/unicode_width_overrides.xml
-    //				 // Combining Ligature Right Half - U+fe21 -https://github.com/microsoft/terminal/blob/main/src/types/unicode_width_overrides.xml
-    public void TestGetColumns_MultiRune_WideBMP (string str, int expected) { Assert.Equal (expected, str.GetColumns ()); }
-
-    [Fact]
-    public void TestGetColumns_Null ()
+    [InlineData ("🙂", 2, 1, 2)]
+    [InlineData ("a🙂", 3, 2, 3)]
+    [InlineData ("🙂a", 3, 2, 3)]
+    [InlineData ("👨‍👩‍👦‍👦", 8, 1, 2)]
+    [InlineData ("👨‍👩‍👦‍👦🙂", 10, 2, 4)]
+    [InlineData ("👨‍👩‍👦‍👦🙂a", 11, 3, 5)]
+    [InlineData ("👨‍👩‍👦‍👦a🙂", 11, 3, 5)]
+    [InlineData ("👨‍👩‍👦‍👦👨‍👩‍👦‍👦", 16, 2, 4)]
+    [InlineData ("าำ", 2, 1, 2)] // า U+0E32 - THAI CHARACTER SARA AA with ำ U+0E33 - THAI CHARACTER SARA AM
+    [InlineData ("山", 2, 1, 2)] // The character for "mountain" in Chinese/Japanese/Korean (山), Unicode U+5C71
+    [InlineData ("山🙂", 4, 2, 4)] // The character for "mountain" in Chinese/Japanese/Korean (山), Unicode U+5C71
+    [InlineData ("a\ufe20e\ufe21", 2, 2, 2)] // Combining Ligature Left Half ︠ - U+fe20 -https://github.com/microsoft/terminal/blob/main/src/types/unicode_width_overrides.xml
+    // Combining Ligature Right Half - U+fe21 -https://github.com/microsoft/terminal/blob/main/src/types/unicode_width_overrides.xml
+    //[InlineData ("क", 1, 1, 1)] // क U+0915 Devanagari Letter Ka
+    //[InlineData ("ि", 1, 1, 1)] // U+093F Devanagari Vowel Sign I ि (i-kar).
+    //[InlineData ("कि", 2, 1, 2)] // "कि" is U+0915 for the base consonant "क" with U+093F for the vowel sign "ि" (i-kar).
+    [InlineData ("ᄀ", 2, 1, 2)] // ᄀ U+1100 HANGUL CHOSEONG KIYEOK (consonant)
+    [InlineData ("ᅡ", 0, 1, 0)] // ᅡ U+1161 HANGUL JUNGSEONG A (vowel)
+    [InlineData ("가", 2, 1, 2)] // ᄀ U+1100 HANGUL CHOSEONG KIYEOK (consonant) with ᅡ U+1161 HANGUL JUNGSEONG A (vowel)
+    [InlineData ("ᄒ", 2, 1, 2)] // ᄒ U+1112 Hangul Choseong Hieuh
+    [InlineData ("ᅵ", 0, 1, 0)] // ᅵ U+1175 Hangul Jungseong I
+    [InlineData ("ᇂ", 0, 1, 0)] // ᇂ U+11C2 Hangul Jongseong Hieuh
+    [InlineData ("힣", 2, 1, 2)] // ᄒ (choseong h) + ᅵ (jungseong i) + ᇂ (jongseong h)
+    [InlineData ("ힰ", 0, 1, 0)]    // U+D7B0 ힰ Hangul Jungseong O-Yeo
+    [InlineData ("ᄀힰ", 2, 1, 2)]  // ᄀ U+1100 HANGUL CHOSEONG KIYEOK (consonant) with U+D7B0 ힰ Hangul Jungseong O-Yeo
+    //[InlineData ("षि", 2, 1, 2)] // U+0937 ष DEVANAGARI LETTER SSA with U+093F ि COMBINING DEVANAGARI VOWEL SIGN I
+    public void TestGetColumns_MultiRune_WideBMP_Graphemes (string str, int expectedRunesWidth, int expectedGraphemesCount, int expectedWidth)
    {
-        string? str = null;
-        Assert.Equal (0, str!.GetColumns ());
-    }
-
-    [Fact]
-    public void TestGetColumns_SingleRune ()
-    {
-        var str = "a";
-        Assert.Equal (1, str.GetColumns ());
-    }
-
-    [Fact]
-    public void TestGetColumns_Zero_Width ()
-    {
-        var str = "\u200D";
-        Assert.Equal (0, str.GetColumns ());
+        Assert.Equal (expectedRunesWidth, str.EnumerateRunes ().Sum (r => r.GetColumns ()));
+        Assert.Equal (expectedGraphemesCount, GraphemeHelper.GetGraphemes (str).ToArray ().Length);
+        Assert.Equal (expectedWidth, str.GetColumns ());
    }

    [Theory]
@@ -70,13 +89,124 @@ public class StringTests
    [InlineData ("")]
    public void TestGetColumns_Does_Not_Throws_With_Null_And_Empty_String (string? text)
    {
-        if (text is null)
+        // ReSharper disable once InvokeAsExtensionMethod
+        Assert.Equal (0, StringExtensions.GetColumns (text!));
+    }
+
+    public class ReadOnlySpanExtensionsTests
+    {
+        [Theory]
+        [InlineData ("12345", true)] // all ASCII digits
+        [InlineData ("0", true)] // single ASCII digit
+        [InlineData ("", false)] // empty span
+        [InlineData ("12a45", false)] // contains a letter
+        [InlineData ("１２３", false)] // full-width Unicode digits (not ASCII)
+        [InlineData ("12 34", false)] // contains space
+        [InlineData ("١٢٣", false)] // Arabic-Indic digits
+        public void IsAllAsciiDigits_WorksAsExpected (string input, bool expected)
        {
-            Assert.Equal (0, StringExtensions.GetColumns (text!));
-        }
-        else
-        {
-            Assert.Equal (0, text.GetColumns ());
+            // Arrange
+            ReadOnlySpan<char> span = input.AsSpan ();
+
+            // Act
+            bool result = span.IsAllAsciiDigits ();
+
+            // Assert
+            Assert.Equal (expected, result);
        }
    }
+
+    [Theory]
+    [InlineData ("0", true)]
+    [InlineData ("9", true)]
+    [InlineData ("A", true)]
+    [InlineData ("F", true)]
+    [InlineData ("a", true)]
+    [InlineData ("f", true)]
+    [InlineData ("123ABC", true)]
+    [InlineData ("abcdef", true)]
+    [InlineData ("G", false)]        // 'G' not hex
+    [InlineData ("Z9", false)]       // 'Z' not hex
+    [InlineData ("12 34", false)]    // space not hex
+    [InlineData ("", false)]         // empty string
+    [InlineData ("１２３", false)]    // full-width digits, not ASCII
+    [InlineData ("0xFF", false)]     // includes 'x'
+    public void IsAllAsciiHexDigits_ReturnsExpected (string input, bool expected)
+    {
+        // Arrange
+        ReadOnlySpan<char> span = input.AsSpan ();
+
+        // Act
+        bool result = span.IsAllAsciiHexDigits ();
+
+        // Assert
+        Assert.Equal (expected, result);
+    }
+
+    [Theory]
+    [MemberData (nameof (GetStringConcatCases))]
+    public void ToString_ReturnsExpected (IEnumerable<string> input, string expected)
+    {
+        // Act
+        string result = StringExtensions.ToString (input);
+
+        // Assert
+        Assert.Equal (expected, result);
+    }
+
+    public static IEnumerable<object []> GetStringConcatCases ()
+    {
+        yield return [new string [] { }, string.Empty]; // Empty sequence
+        yield return [new [] { "" }, string.Empty]; // Single empty string
+        yield return [new [] { "A" }, "A"]; // Single element
+        yield return [new [] { "A", "B" }, "AB"]; // Simple concatenation
+        yield return [new [] { "Hello", " ", "World" }, "Hello World"]; // Multiple parts
+        yield return [new [] { "123", "456", "789" }, "123456789"]; // Numeric strings
+        yield return [new [] { "👩‍", "🧒" }, "👩‍🧒"]; // Grapheme sequence
+        yield return [new [] { "α", "β", "γ" }, "αβγ"]; // Unicode letters
+        yield return [new [] { "A", null, "B" }, "AB"]; // Null ignored by string.Concat
+    }
+
+    [Theory]
+    [InlineData ("", false)]                                // Empty string
+    [InlineData ("A", false)]                               // Single BMP character
+    [InlineData ("AB", false)]                              // Two BMP chars, not a surrogate pair
+    [InlineData ("👩", true)]                               // Single emoji surrogate pair (U+1F469)
+    [InlineData ("🧒", true)]                               // Another emoji surrogate pair (U+1F9D2)
+    [InlineData ("𐍈", true)]                               // Gothic letter hwair (U+10348)
+    [InlineData ("A👩", false)]                             // One BMP + one surrogate half
+    [InlineData ("👩‍", false)]                              // Surrogate pair + ZWJ (length != 2)
+    public void IsSurrogatePair_ReturnsExpected (string input, bool expected)
+    {
+        // Act
+        bool result = input.IsSurrogatePair ();
+
+        // Assert
+        Assert.Equal (expected, result);
+    }
+
+    [Theory]
+    // Control characters (should be replaced with the "Control Pictures" block)
+    [InlineData ("\u0000", "\u2400")]  // NULL → ␀
+    [InlineData ("\u0009", "\u2409")]  // TAB → ␉
+    [InlineData ("\u000A", "\u240A")]  // LF → ␊
+    [InlineData ("\u000D", "\u240D")]  // CR → ␍
+
+    // Printable characters (should remain unchanged)
+    [InlineData ("A", "A")]
+    [InlineData (" ", " ")]
+    [InlineData ("~", "~")]
+
+    // Multi-character string (should return unchanged)
+    [InlineData ("AB", "AB")]
+    [InlineData ("Hello", "Hello")]
+    [InlineData ("\u0009A", "\u0009A")] // includes a control char, but length > 1
+    public void MakePrintable_ReturnsExpected (string input, string expected)
+    {
+        // Act
+        string result = input.MakePrintable ();
+
+        // Assert
+        Assert.Equal (expected, result);
+    }
 }
--- a/Tests/UnitTestsParallelizable/Text/TextFormatterDrawTests.cs
+++ b/Tests/UnitTestsParallelizable/Text/TextFormatterDrawTests.cs
@@ -658,5 +658,32 @@ Nice       Work")]
        DriverAssert.AssertDriverContentsWithFrameAre (expectedDraw, output, driver);
    }

+    [Theory]
+    [InlineData ("\U0001F468\u200D\U0001F469\u200D\U0001F467\u200D\U0001F466", 2, 1, TextDirection.LeftRight_TopBottom, "👨‍👩‍👧‍👦")]
+    [InlineData ("\U0001F468\u200D\U0001F469\u200D\U0001F467\u200D\U0001F466", 2, 1, TextDirection.TopBottom_LeftRight, "👨‍👩‍👧‍👦")]
+    public void Draw_Emojis_With_Zero_Width_Joiner (
+        string text,
+        int width,
+        int height,
+        TextDirection direction,
+        string expectedDraw
+    )
+    {
+        IDriver driver = CreateFakeDriver ();
+
+        TextFormatter tf = new ()
+        {
+            Direction = direction,
+            ConstrainToSize = new (width, height),
+            Text = text,
+            WordWrap = false
+        };
+        Assert.Equal (width, text.GetColumns ());
+
+        tf.Draw (driver, new (0, 0, width, height), Attribute.Default, Attribute.Default);
+
+        DriverAssert.AssertDriverContentsWithFrameAre (expectedDraw, output, driver);
+    }
+
    #endregion
 }
--- a/Tests/UnitTestsParallelizable/Text/TextFormatterTests.cs
+++ b/Tests/UnitTestsParallelizable/Text/TextFormatterTests.cs
@@ -792,19 +792,16 @@ public class TextFormatterTests (ITestOutputHelper output) : FakeDriverBase
    [MemberData (nameof (CMGlyphs))]
    public void GetLengthThatFits_List_Simple_And_Wide_Runes (string text, int columns, int expectedLength)
    {
-        List<Rune> runes = text.ToRuneList ();
-        Assert.Equal (expectedLength, TextFormatter.GetLengthThatFits (runes, columns));
+        Assert.Equal (expectedLength, TextFormatter.GetLengthThatFits (text, columns));
    }

    [Theory]
    [InlineData ("test", 3, 3)]
    [InlineData ("test", 4, 4)]
    [InlineData ("test", 10, 4)]
-    public void GetLengthThatFits_Runelist (string text, int columns, int expectedLength)
+    public void GetLengthThatFits_For_String (string text, int columns, int expectedLength)
    {
-        List<Rune> runes = text.ToRuneList ();
-
-        Assert.Equal (expectedLength, TextFormatter.GetLengthThatFits (runes, columns));
+        Assert.Equal (expectedLength, TextFormatter.GetLengthThatFits (text, columns));
    }

    [Theory]
@@ -833,7 +830,8 @@ public class TextFormatterTests (ITestOutputHelper output) : FakeDriverBase
    public void GetLengthThatFits_With_Combining_Runes ()
    {
        var text = "Les Mise\u0328\u0301rables";
-        Assert.Equal (16, TextFormatter.GetLengthThatFits (text, 14));
+        Assert.Equal (14, TextFormatter.GetLengthThatFits (text, 14));
+        Assert.Equal ("Les Misę́rables", text);
    }

    [Fact]
@@ -841,14 +839,18 @@ public class TextFormatterTests (ITestOutputHelper output) : FakeDriverBase
    {
        List<string> text = new () { "Les Mis", "e\u0328\u0301", "rables" };
        Assert.Equal (1, TextFormatter.GetMaxColsForWidth (text, 1));
+        Assert.Equal ("Les Mis", text [0]);
+        Assert.Equal ("ę́", text [1]);
+        Assert.Equal ("rables", text [^1]);
    }

-    //[Fact]
-    //public void GetWidestLineLength_With_Combining_Runes ()
-    //{
-    //    var text = "Les Mise\u0328\u0301rables";
-    //    Assert.Equal (1, TextFormatter.GetWidestLineLength (text, 1, 1));
-    //}
+    [Fact]
+    public void GetWidestLineLength_With_Combining_Runes ()
+    {
+        var text = "Les Mise\u0328\u0301rables";
+        Assert.Equal (14, TextFormatter.GetWidestLineLength (text, 1));
+        Assert.Equal ("Les Misę́rables", text);
+    }

    [Fact]
    public void Internal_Tests ()
@@ -2451,6 +2453,7 @@ public class TextFormatterTests (ITestOutputHelper output) : FakeDriverBase
        Assert.Equal (expected, breakLines);

        // Double space Complex example - this is how VS 2022 does it
+        // which I think is not correct.
        //text = "A  sentence      has words.  ";
        //breakLines = "";
        //wrappedLines = TextFormatter.WordWrapText (text, width, preserveTrailingSpaces: true);
@@ -2762,8 +2765,7 @@ public class TextFormatterTests (ITestOutputHelper output) : FakeDriverBase
                        "ฮ",
                        "ฯ",
                        "ะั",
-                        "า",
-                        "ำ"
+                        "าำ"
                    }
                )]
    public void WordWrap_Unicode_SingleWordLine (
@@ -2798,7 +2800,17 @@ public class TextFormatterTests (ITestOutputHelper output) : FakeDriverBase
        Assert.True (
                     expectedClippedWidth >= (wrappedLines.Count > 0 ? wrappedLines.Max (l => l.GetColumns ()) : 0)
                    );
-        Assert.Equal (resultLines, wrappedLines);
+
+        if (maxWidth == 1)
+        {
+            List<string> newResultLines = resultLines.ToList ();
+            newResultLines [^1] = "";
+            Assert.Equal (newResultLines, wrappedLines);
+        }
+        else
+        {
+            Assert.Equal (resultLines, wrappedLines);
+        }
    }

    /// <summary>WordWrap strips CRLF</summary>
@@ -3075,8 +3087,8 @@ public class TextFormatterTests (ITestOutputHelper output) : FakeDriverBase
    }

    [Theory]
-    [InlineData (14, 1, TextDirection.LeftRight_TopBottom, "Les Misęrables")]
-    [InlineData (1, 14, TextDirection.TopBottom_LeftRight, "L\ne\ns\n \nM\ni\ns\nę\nr\na\nb\nl\ne\ns")]
+    [InlineData (14, 1, TextDirection.LeftRight_TopBottom, "Les Misę́rables")]
+    [InlineData (1, 14, TextDirection.TopBottom_LeftRight, "L\ne\ns\n \nM\ni\ns\nę́\nr\na\nb\nl\ne\ns")]
    [InlineData (
                    4,
                    4,
@@ -3085,7 +3097,7 @@ public class TextFormatterTests (ITestOutputHelper output) : FakeDriverBase
 LMre
 eias
 ssb 
- ęl "
+ ę́l "
                )]
    public void Draw_With_Combining_Runes (int width, int height, TextDirection textDirection, string expected)
    {
@@ -3111,7 +3123,6 @@ ssb
        driver.End ();
    }

-
    [Theory]
    [InlineData (17, 1, TextDirection.LeftRight_TopBottom, 4, "This is a     Tab")]
    [InlineData (1, 17, TextDirection.TopBottom_LeftRight, 4, "T\nh\ni\ns\n \ni\ns\n \na\n \n \n \n \n \nT\na\nb")]
@@ -3187,7 +3198,6 @@ ssb
        driver.End ();
    }

-
    [Theory]
    [InlineData (17, 1, TextDirection.LeftRight_TopBottom, 4, "This is a     Tab")]
    [InlineData (1, 17, TextDirection.TopBottom_LeftRight, 4, "T\nh\ni\ns\n \ni\ns\n \na\n \n \n \n \n \nT\na\nb")]
@@ -3224,5 +3234,4 @@ ssb

        driver.End ();
    }
-
 }