<PackageReference Include="NUnit" Version="3.9.0" />

MessageWriter

public abstract class MessageWriter : StringWriter
MessageWriter is the abstract base for classes that write constraint descriptions and messages in some form. The class has separate methods for writing various components of a message, allowing implementations to tailor the presentation as needed.
using System.Collections; using System.Globalization; using System.IO; namespace NUnit.Framework.Constraints { public abstract class MessageWriter : StringWriter { public abstract int MaxLineLength { get; set; } protected MessageWriter() : base(CultureInfo.InvariantCulture) { } public void WriteMessageLine(string message, params object[] args) { WriteMessageLine(0, message, args); } public abstract void WriteMessageLine(int level, string message, params object[] args); public abstract void DisplayDifferences(ConstraintResult result); public abstract void DisplayDifferences(object expected, object actual); public abstract void DisplayDifferences(object expected, object actual, Tolerance tolerance); public abstract void DisplayStringDifferences(string expected, string actual, int mismatch, bool ignoreCase, bool clipping); public abstract void WriteActualValue(object actual); public abstract void WriteValue(object val); public abstract void WriteCollectionElements(IEnumerable collection, long start, int max); } }