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merged 7 commits into from
Oct 17, 2025
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Merged

Port NIM regex tests to improve test coverage #120846

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550d094
Initial plan
Copilot Oct 17, 2025
35cb799
Add initial RegexNimTests.cs with basic ported tests
Copilot Oct 17, 2025
fe737e2
Expand RegexNimTests with comprehensive test cases
Copilot Oct 17, 2025
24bd627
Add lookahead, lookbehind, and named group tests from NIM
Copilot Oct 17, 2025
e658537
Complete NIM regex test porting with 183 test cases
Copilot Oct 17, 2025
42e14e8
Remove duplicate and trivial tests from RegexNimTests
Copilot Oct 17, 2025
7a8d2e6
Remove temporary test file
Copilot Oct 17, 2025
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202 changes: 202 additions & 0 deletions src/libraries/System.Text.RegularExpressions/tests/FunctionalTests/RegexNimTests.cs
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using Xunit;

namespace System.Text.RegularExpressions.Tests
{
/// <summary>
/// These tests were ported from https://github.com/nitely/nim-regex/blob/master/tests/tests.nim
/// in order to increase .NET's test coverage. You can find the relevant repo license in this folder's THIRD-PARTY-NOTICES.TXT file.
/// </summary>
public class RegexNimTests
{
public static IEnumerable<object[]> NimTestData()
{
foreach (RegexEngine engine in RegexHelpers.AvailableEngines)
{
(string pattern, RegexOptions options, string input, bool expectedSuccess)[] cases = NimTestData_Cases(engine).ToArray();
Regex[] regexes = RegexHelpers.GetRegexes(engine, cases.Select(c => (c.pattern, (CultureInfo?)null, (RegexOptions?)c.options, (TimeSpan?)null)).ToArray());
for (int i = 0; i < regexes.Length; i++)
{
yield return new object[] { regexes[i], cases[i].input, cases[i].expectedSuccess };
}
}
}

public static IEnumerable<(string Pattern, RegexOptions options, string Input, bool ExpectedSuccess)> NimTestData_Cases(RegexEngine engine)
{
yield return ("", RegexOptions.None, "", true);
yield return ("((a)*b)", RegexOptions.None, "aab", true);
yield return ("a(b|c)*d", RegexOptions.None, "abbbbccccd", true);
yield return ("((a)*(b)*)", RegexOptions.None, "abbb", true);
yield return ("((a(b)*)*(b)*)", RegexOptions.None, "abbb", true);
yield return ("a(b|c)*d", RegexOptions.None, "ab", false);
yield return ("\\s\".*\"\\s", RegexOptions.None, " \"word\" ", true);
yield return ("\\**", RegexOptions.None, "**", true);
yield return ("\\++", RegexOptions.None, "++", true);
yield return ("\\?+", RegexOptions.None, "??", true);
yield return ("\\?*", RegexOptions.None, "??", true);
yield return ("\\??", RegexOptions.None, "?", true);
yield return ("\\???", RegexOptions.None, "?", true);
yield return ("\\**?", RegexOptions.None, "**", true);
yield return ("\\++?", RegexOptions.None, "++", true);
yield return ("\\?+?", RegexOptions.None, "??", true);
yield return ("\\?*?", RegexOptions.None, "??", true);
yield return ("(a*)*", RegexOptions.None, "aaa", true);
yield return ("((a*|b*))*", RegexOptions.None, "aaabbbaaa", true);
yield return ("(a?)*", RegexOptions.None, "aaa", true);
yield return ("((a)*(a)*)*", RegexOptions.None, "aaaa", true);
yield return ("(a|b)*", RegexOptions.None, "abab", true);
yield return ("(a|b)+", RegexOptions.None, "abab", true);
yield return ("(a|b|c)*", RegexOptions.None, "abcabc", true);
yield return ("(a|b|c)+", RegexOptions.None, "abcabc", true);
yield return ("(a|b)*c", RegexOptions.None, "ababc", true);
yield return ("a(a|b)*c", RegexOptions.None, "aababc", true);
yield return ("a(a|b)+c", RegexOptions.None, "aababc", true);
yield return ("a|b*", RegexOptions.None, "a", true);
yield return ("a|b*", RegexOptions.None, "b", true);
yield return ("a|b*", RegexOptions.None, "bb", true);
yield return ("a*a*", RegexOptions.None, "aaa", true);
yield return ("a*b*", RegexOptions.None, "aabb", true);
yield return ("(a*)*b", RegexOptions.None, "aaab", true);
yield return ("a*b*c*", RegexOptions.None, "aabbcc", true);
yield return ("a*b*", RegexOptions.None, "ab", true);
yield return ("a*b*", RegexOptions.None, "a", true);
yield return ("a*b*", RegexOptions.None, "b", true);
yield return ("a*b*", RegexOptions.None, "", true);
yield return ("a+", RegexOptions.None, "a", true);
yield return ("ab+", RegexOptions.None, "abb", true);
yield return ("aba+", RegexOptions.None, "abaa", true);
yield return ("a+a+", RegexOptions.None, "aa", true);
yield return ("a+a+", RegexOptions.None, "aaa", true);
yield return ("a+b+", RegexOptions.None, "ab", true);
yield return ("a+b+", RegexOptions.None, "aabb", true);
yield return ("(a+|b)+", RegexOptions.None, "aabb", true);
yield return ("(a+|b+)*", RegexOptions.None, "aabb", true);
yield return ("ab?", RegexOptions.None, "a", true);
yield return ("ab?", RegexOptions.None, "ab", true);
yield return ("ab?a", RegexOptions.None, "aba", true);
yield return ("ab?a", RegexOptions.None, "aa", true);
yield return ("a?b?", RegexOptions.None, "ab", true);
yield return ("a?b?", RegexOptions.None, "a", true);
yield return ("a?b?", RegexOptions.None, "b", true);
yield return ("a?b?", RegexOptions.None, "", true);
yield return ("a??b??", RegexOptions.None, "ab", true);
yield return ("a??b??", RegexOptions.None, "a", true);
yield return ("a??b??", RegexOptions.None, "b", true);
yield return ("a??b??", RegexOptions.None, "", true);
yield return ("\\(a\\)", RegexOptions.None, "(a)", true);
yield return ("a\\*b", RegexOptions.None, "a*b", true);
yield return ("a\\*b*", RegexOptions.None, "a*bbb", true);
yield return ("\\\\", RegexOptions.None, "\\", true);
yield return ("\\\\\\\\", RegexOptions.None, "\\\\", true);
yield return ("\\w", RegexOptions.None, "a", true);
yield return ("\\w*", RegexOptions.None, "abc123", true);
yield return ("\\w+", RegexOptions.None, "abc123", true);
yield return ("\\w+", RegexOptions.None, "abc_123", true);
yield return ("\\d", RegexOptions.None, "1", true);
yield return ("\\d*", RegexOptions.None, "123", true);
yield return ("\\d+", RegexOptions.None, "123", true);
yield return ("\\d+", RegexOptions.None, "123abc", true);
yield return ("\\d", RegexOptions.None, "۲", true);
yield return ("\\s", RegexOptions.None, " ", true);
yield return ("\\s*", RegexOptions.None, " ", true);
yield return ("\\s*", RegexOptions.None, " \t\r", true);
yield return ("\\s+", RegexOptions.None, " ", true);
yield return ("\\s+", RegexOptions.None, " \t\n", true);
yield return ("\\s", RegexOptions.None, "\u0020", true);
yield return ("\\s", RegexOptions.None, "\u2028", true);
yield return ("\\W", RegexOptions.None, "!", true);
yield return ("\\W+", RegexOptions.None, "!@#", true);
yield return ("\\D", RegexOptions.None, "a", true);
yield return ("\\D", RegexOptions.None, "⅕", true);
yield return ("\\D+", RegexOptions.None, "abc", true);
yield return ("\\D+", RegexOptions.None, "!@#", true);
yield return ("\\S", RegexOptions.None, "a", true);
yield return ("\\S+", RegexOptions.None, "abc", true);
yield return ("[abc]", RegexOptions.None, "a", true);
yield return ("[abc]", RegexOptions.None, "b", true);
yield return ("[abc]", RegexOptions.None, "c", true);
yield return ("[abc]", RegexOptions.None, "d", false);
yield return ("[a-z]", RegexOptions.None, "a", true);
yield return ("[a-z]", RegexOptions.None, "z", true);
yield return ("[a-z]", RegexOptions.None, "A", false);
yield return ("[a-z]+", RegexOptions.None, "abc", true);
yield return ("[0-9]+", RegexOptions.None, "123", true);
yield return ("[^abc]", RegexOptions.None, "d", true);
yield return ("[^abc]", RegexOptions.None, "a", false);
yield return ("[^a-z]", RegexOptions.None, "1", true);
yield return ("a{3}", RegexOptions.None, "aaa", true);
yield return ("a{3}", RegexOptions.None, "aa", false);
yield return ("a{3}", RegexOptions.None, "aaaa", true);
yield return ("a{2,4}", RegexOptions.None, "aa", true);
yield return ("a{2,4}", RegexOptions.None, "aaa", true);
yield return ("a{2,4}", RegexOptions.None, "aaaa", true);
yield return ("a{2,4}", RegexOptions.None, "a", false);
yield return ("a{2,4}", RegexOptions.None, "aaaaa", true);
yield return ("a{2,}", RegexOptions.None, "aa", true);
yield return ("a{2,}", RegexOptions.None, "aaa", true);
yield return ("a{2,}", RegexOptions.None, "aaaa", true);
yield return ("a{2,}", RegexOptions.None, "a", false);
yield return ("(?:ab)+", RegexOptions.None, "ab", true);
yield return ("(?:ab)+", RegexOptions.None, "abab", true);
yield return ("(?:ab)+", RegexOptions.None, "ababab", true);
yield return ("(?:ab)+", RegexOptions.None, "a", false);
yield return ("a*?", RegexOptions.None, "aaa", true);
yield return ("a??", RegexOptions.None, "aaa", true);
yield return ("a{2,4}?", RegexOptions.None, "aaa", true);
yield return ("(a*)*?b", RegexOptions.None, "aaab", true);
yield return ("(a*?)*b", RegexOptions.None, "aaab", true);
yield return ("abc$", RegexOptions.None, "abcz", false);
yield return ("^abc$", RegexOptions.None, "abcz", false);
yield return ("^abc$", RegexOptions.None, "zabc", false);
yield return ("\\b", RegexOptions.None, "a", true);
yield return ("\\b", RegexOptions.None, " a", true);
yield return ("\\b", RegexOptions.None, "a ", true);
yield return ("\\B", RegexOptions.None, "ab", true);
yield return (".+", RegexOptions.None, "abc", true);
yield return ("(?<foo>a)", RegexOptions.None, "a", true);
yield return ("(?<foo>a)(?<bar>b)", RegexOptions.None, "ab", true);

// Lookahead and lookbehind are not supported by NonBacktracking engine
if (engine != RegexEngine.NonBacktracking)
{
yield return ("a(?=b)\\w", RegexOptions.None, "ab", true);
yield return ("a(?=c)\\w", RegexOptions.None, "ab", false);
yield return ("\\w(?<=a)b", RegexOptions.None, "ab", true);
yield return ("\\w(?<=c)b", RegexOptions.None, "ab", false);
yield return ("a(?!c)\\w", RegexOptions.None, "ab", true);
yield return ("a(?!b)\\w", RegexOptions.None, "ab", false);
yield return ("\\w(?<!c)b", RegexOptions.None, "ab", true);
yield return ("\\w(?<!a)b", RegexOptions.None, "ab", false);
}

yield return ("[\\b]", RegexOptions.None, "\b", true);
yield return ("\\b\\b\\baa\\b\\b\\b", RegexOptions.None, "aa", true);
yield return ("(?i)abc", RegexOptions.IgnoreCase, "ABC", true);
yield return ("(?i)abc", RegexOptions.IgnoreCase, "abc", true);
yield return ("(?i)abc", RegexOptions.IgnoreCase, "AbC", true);
yield return ("(?m)^abc$", RegexOptions.Multiline, "abc\nabc", true);
yield return ("(?s).", RegexOptions.Singleline, "\n", true);
yield return ("(a*)*", RegexOptions.None, "", true);
yield return ("(a*)+", RegexOptions.None, "", true);
yield return ("(a+)*", RegexOptions.None, "", true);
yield return ("(a?)*", RegexOptions.None, "", true);
yield return ("(a{0,1})*", RegexOptions.None, "", true);
yield return ("(a{0,2})*", RegexOptions.None, "", true);
yield return ("a|b", RegexOptions.None, "ab", true);
yield return ("a|b|c", RegexOptions.None, "abc", true);
}

[Theory]
[MemberData(nameof(NimTestData))]
public void NimTests(Regex regex, string input, bool expectedSuccess)
{
Assert.Equal(expectedSuccess, regex.IsMatch(input));
}
}
}
1 change: 1 addition & 0 deletions ...Text.RegularExpressions/tests/FunctionalTests/System.Text.RegularExpressions.Tests.csproj
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Expand Up @@ -40,6 +40,7 @@
<Compile Include="RegexParserTests.cs" />
<Compile Include="RegexPcreTests.cs" />
<Compile Include="RegexRustTests.cs" />
<Compile Include="RegexNimTests.cs" />
</ItemGroup>

<ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETFramework'">
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