<PackageReference Include="NUnit" Version="4.2.2" />

StartsWithConstraint

StartsWithConstraint can test whether a string starts with an expected substring.
using System; using System.Runtime.CompilerServices; namespace NUnit.Framework.Constraints { public class StartsWithConstraint : StringConstraint { [System.Runtime.CompilerServices.NullableContext(1)] public StartsWithConstraint(string expected) : base(expected) { descriptionText = "String starting with"; } [System.Runtime.CompilerServices.NullableContext(2)] protected override bool Matches(string actual) { StringComparison comparisonType = caseInsensitive ? StringComparison.CurrentCultureIgnoreCase : StringComparison.CurrentCulture; return actual?.StartsWith(expected, comparisonType) ?? false; } } }