fix: failure messages of EquivalencyComparer

Source/aweXpect.Core/Core/Polyfills/ReferenceEqualityComparer.cs

@@ -2,6 +2,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 
 // ReSharper disable once CheckNamespace
@@ -17,6 +18,7 @@ namespace System.Collections.Generic
 	///     property
 	///     to access the singleton instance of this type.
 	/// </remarks>
+	[ExcludeFromCodeCoverage]
 	internal sealed class ReferenceEqualityComparer : IEqualityComparer<object?>, IEqualityComparer
 	{
 		private ReferenceEqualityComparer() { }

Source/aweXpect/Equivalency/EquivalencyComparer.cs

@@ -36,7 +36,7 @@ public string GetExtendedFailure(string it, ExpectationGrammars grammars, object
 	{
 		if (grammars.HasFlag(ExpectationGrammars.Negated))
 		{
-			return $"{it} was considered equivalent to {Formatter.Format(actual, FormattingOptions.Indented())}";
+			return $"{it} was considered equivalent for {Formatter.Format(actual, FormattingOptions.Indented())}";
 		}
 
 		if (actual is null != expected is null)
@@ -50,14 +50,9 @@ public string GetExtendedFailure(string it, ExpectationGrammars grammars, object
 			return _failureBuilder.ToString();
 		}
 
-		if (_failureBuilder.Length > 0)
-		{
-			_failureBuilder.Insert(0, " was not:");
-			_failureBuilder.Insert(0, it);
-			return _failureBuilder.ToString();
-		}
-
-		return $"{it} was considered equivalent";
+		_failureBuilder.Insert(0, " was not:");
+		_failureBuilder.Insert(0, it);
+		return _failureBuilder.ToString();
 	}
 
 	private static bool HandleSpecialCases<TActual, TExpected>(TActual actual, TExpected expected,
@@ -69,6 +64,13 @@ private static bool HandleSpecialCases<TActual, TExpected>(TActual actual, TExpe
 			isConsideredEqual = actualEqualityComparer.Equals(actual, expected);
 			if (isConsideredEqual == false)
 			{
+				failureBuilder.AppendLine();
+				if (failureBuilder.Length > 2)
+				{
+					failureBuilder.AppendLine("and");
+				}
+
+				failureBuilder.Append("  ");
 				Formatter.Format(failureBuilder, actual, FormattingOptions.SingleLine);
 				failureBuilder.Append(" did not equal ");
 				Formatter.Format(failureBuilder, expected, FormattingOptions.SingleLine);
@@ -82,6 +84,13 @@ private static bool HandleSpecialCases<TActual, TExpected>(TActual actual, TExpe
 			isConsideredEqual = expectedEqualityComparer.Equals(actual, expected);
 			if (isConsideredEqual == false)
 			{
+				failureBuilder.AppendLine();
+				if (failureBuilder.Length > 2)
+				{
+					failureBuilder.AppendLine("and");
+				}
+
+				failureBuilder.Append("  ");
 				Formatter.Format(failureBuilder, actual, FormattingOptions.SingleLine);
 				failureBuilder.Append(" did not equal ");
 				Formatter.Format(failureBuilder, expected, FormattingOptions.SingleLine);

Source/aweXpect/That/Exceptions/ThatException.HasParamName.cs

@@ -42,20 +42,38 @@ public ConstraintResult IsMetBy(Exception? actual)
 
 		protected override void AppendNormalExpectation(StringBuilder stringBuilder, string? indentation = null)
 		{
-			if (Grammars.HasFlag(ExpectationGrammars.Active))
+			if (expected is null)
 			{
-				stringBuilder.Append("with ParamName ");
-			}
-			else if (Grammars.HasFlag(ExpectationGrammars.Nested))
-			{
-				stringBuilder.Append("ParamName is ");
+				if (Grammars.HasFlag(ExpectationGrammars.Active))
+				{
+					stringBuilder.Append("with a ParamName");
+				}
+				else if (Grammars.HasFlag(ExpectationGrammars.Nested))
+				{
+					stringBuilder.Append("ParamName exists");
+				}
+				else
+				{
+					stringBuilder.Append("has a ParamName");
+				}
 			}
 			else
 			{
-				stringBuilder.Append("has ParamName ");
-			}
+				if (Grammars.HasFlag(ExpectationGrammars.Active))
+				{
+					stringBuilder.Append("with ParamName ");
+				}
+				else if (Grammars.HasFlag(ExpectationGrammars.Nested))
+				{
+					stringBuilder.Append("ParamName is ");
+				}
+				else
+				{
+					stringBuilder.Append("has ParamName ");
+				}
 
-			Formatter.Format(stringBuilder, expected);
+				Formatter.Format(stringBuilder, expected);
+			}
 		}
 
 		protected override void AppendNormalResult(StringBuilder stringBuilder, string? indentation = null)
@@ -65,29 +83,42 @@ protected override void AppendNormalResult(StringBuilder stringBuilder, string?
 				stringBuilder.Append(It).Append(" had ParamName ");
 				Formatter.Format(stringBuilder, argumentException.ParamName);
 			}
-			else
-			{
-				stringBuilder.Append(It).Append(" was ");
-				Formatter.Format(stringBuilder, Actual);
-			}
 		}
 
 		protected override void AppendNegatedExpectation(StringBuilder stringBuilder, string? indentation = null)
 		{
-			if (Grammars.HasFlag(ExpectationGrammars.Active))
-			{
-				stringBuilder.Append("without ParamName ");
-			}
-			else if (Grammars.HasFlag(ExpectationGrammars.Nested))
+			if (expected is null)
 			{
-				stringBuilder.Append("ParamName is not ");
+				if (Grammars.HasFlag(ExpectationGrammars.Active))
+				{
+					stringBuilder.Append("without a ParamName");
+				}
+				else if (Grammars.HasFlag(ExpectationGrammars.Nested))
+				{
+					stringBuilder.Append("ParamName does not exist");
+				}
+				else
+				{
+					stringBuilder.Append("does not have a ParamName");
+				}
 			}
 			else
 			{
-				stringBuilder.Append("does not have ParamName ");
-			}
+				if (Grammars.HasFlag(ExpectationGrammars.Active))
+				{
+					stringBuilder.Append("without ParamName ");
+				}
+				else if (Grammars.HasFlag(ExpectationGrammars.Nested))
+				{
+					stringBuilder.Append("ParamName is not ");
+				}
+				else
+				{
+					stringBuilder.Append("does not have ParamName ");
+				}
 
-			Formatter.Format(stringBuilder, expected);
+				Formatter.Format(stringBuilder, expected);
+			}
 		}
 
 		protected override void AppendNegatedResult(StringBuilder stringBuilder, string? indentation = null)

Tests/aweXpect.Internal.Tests/ThatTests/Exceptions/HasParamNameValueConstraintTests.cs

@@ -0,0 +1,43 @@
+using System.Text;
+using aweXpect.Core;
+
+namespace aweXpect.Internal.Tests.ThatTests.Exceptions;
+
+public class HasParamNameValueConstraintTests
+{
+	[Theory]
+	[InlineData(ExpectationGrammars.None, "has ParamName \"foo\"")]
+	[InlineData(ExpectationGrammars.Negated, "does not have ParamName \"foo\"")]
+	[InlineData(ExpectationGrammars.Nested, "ParamName is \"foo\"")]
+	[InlineData(ExpectationGrammars.Nested | ExpectationGrammars.Negated, "ParamName is not \"foo\"")]
+	[InlineData(ExpectationGrammars.Active, "with ParamName \"foo\"")]
+	[InlineData(ExpectationGrammars.Active | ExpectationGrammars.Negated, "without ParamName \"foo\"")]
+	public async Task AppendExpectation_WithExpected_ShouldAppendExpectedText(ExpectationGrammars grammar,
+		string expected)
+	{
+		ThatException.HasParamNameValueConstraint<ArgumentException> sut = new("it", grammar, "foo");
+		StringBuilder sb = new();
+
+		sut.AppendExpectation(sb, "");
+
+		await That(sb.ToString()).IsEqualTo(expected);
+	}
+
+	[Theory]
+	[InlineData(ExpectationGrammars.None, "has a ParamName")]
+	[InlineData(ExpectationGrammars.Negated, "does not have a ParamName")]
+	[InlineData(ExpectationGrammars.Nested, "ParamName exists")]
+	[InlineData(ExpectationGrammars.Nested | ExpectationGrammars.Negated, "ParamName does not exist")]
+	[InlineData(ExpectationGrammars.Active, "with a ParamName")]
+	[InlineData(ExpectationGrammars.Active | ExpectationGrammars.Negated, "without a ParamName")]
+	public async Task AppendExpectation_WithNullAsExpected_ShouldAppendExpectedText(ExpectationGrammars grammar,
+		string expected)
+	{
+		ThatException.HasParamNameValueConstraint<ArgumentException> sut = new("it", grammar, null);
+		StringBuilder sb = new();
+
+		sut.AppendExpectation(sb, "");
+
+		await That(sb.ToString()).IsEqualTo(expected);
+	}
+}

Tests/aweXpect.Tests/Exceptions/ThatException.HasParamName.Tests.cs

@@ -75,5 +75,91 @@ but it was <null>
 					             """);
 			}
 		}
+		public sealed class NegatedTests
+		{
+			[Theory]
+			[AutoData]
+			public async Task WhenExpectedIsNull_AndParamNameIsEmpty_ShouldFail(string message)
+			{
+				ArgumentException subject = new(message);
+
+				async Task Act()
+					=> await That(subject).DoesNotComplyWith(it =>
+						it.HasParamName(null));
+
+				await That(Act).Throws<XunitException>()
+					.WithMessage("""
+					             Expected that subject
+					             does not have a ParamName,
+					             but it had
+					             """);
+			}
+
+			[Theory]
+			[AutoData]
+			public async Task WhenExpectedIsNull_ShouldFail(string message)
+			{
+				ArgumentException subject = new(message, nameof(message));
+
+				async Task Act()
+					=> await That(subject).DoesNotComplyWith(it =>
+						it.HasParamName(null));
+
+				await That(Act).Throws<XunitException>()
+					.WithMessage("""
+					             Expected that subject
+					             does not have a ParamName,
+					             but it had
+					             """);
+			}
+
+			[Theory]
+			[AutoData]
+			public async Task WhenParamNameIsDifferent_ShouldSucceed(string message)
+			{
+				ArgumentException subject = new(message, nameof(message));
+
+				async Task Act()
+					=> await That(subject).DoesNotComplyWith(it =>
+						it.HasParamName("somethingElse"));
+
+				await That(Act).DoesNotThrow();
+			}
+
+			[Theory]
+			[AutoData]
+			public async Task WhenParamNameMatchesExpected_ShouldFail(string message)
+			{
+				ArgumentException subject = new(message, nameof(message));
+
+				async Task Act()
+					=> await That(subject).DoesNotComplyWith(it =>
+						it.HasParamName("message"));
+
+				await That(Act).Throws<XunitException>()
+					.WithMessage("""
+					             Expected that subject
+					             does not have ParamName "message",
+					             but it had
+					             """);
+			}
+
+			[Fact]
+			public async Task WhenSubjectIsNull_ShouldFail()
+			{
+				ArgumentException? subject = null;
+
+				async Task Act()
+					=> await That(subject).DoesNotComplyWith(it =>
+						it.HasParamName("message"));
+
+				await That(Act).Throws<XunitException>()
+					.WithMessage("""
+					             Expected that subject
+					             does not have ParamName "message",
+					             but it was <null>
+					             """);
+			}
+		}
 	}
 }