Apply structured assertion messages to IsTrue, IsFalse, IsNull, IsNotNull

src/TestFramework/TestFramework/Assertions/Assert.IsNull.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System.ComponentModel;
@@ -22,9 +22,11 @@ public sealed partial class Assert
     public readonly struct AssertIsNullInterpolatedStringHandler
     {
         private readonly StringBuilder? _builder;
+        private readonly object? _value;
 
         public AssertIsNullInterpolatedStringHandler(int literalLength, int formattedCount, object? value, out bool shouldAppend)
         {
+            _value = value;
             shouldAppend = IsNullFailing(value);
             if (shouldAppend)
             {
@@ -36,8 +38,7 @@ internal void ComputeAssertion(string valueExpression)
         {
             if (_builder is not null)
             {
-                _builder.Insert(0, string.Format(CultureInfo.CurrentCulture, FrameworkMessages.CallerArgumentExpressionSingleParameterMessage, "value", valueExpression) + " ");
-                ReportAssertIsNullFailed(_builder.ToString());
+                ReportAssertIsNullFailed(_value, _builder.ToString(), valueExpression);
             }
         }
 
@@ -90,8 +91,7 @@ internal void ComputeAssertion(string valueExpression)
         {
             if (_builder is not null)
             {
-                _builder.Insert(0, string.Format(CultureInfo.CurrentCulture, FrameworkMessages.CallerArgumentExpressionSingleParameterMessage, "value", valueExpression) + " ");
-                ReportAssertIsNotNullFailed(_builder.ToString());
+                ReportAssertIsNotNullFailed(_builder.ToString(), valueExpression);
             }
         }
 
@@ -152,14 +152,26 @@ public static void IsNull(object? value, string? message = "", [CallerArgumentEx
     {
         if (IsNullFailing(value))
         {
-            ReportAssertIsNullFailed(BuildUserMessageForValueExpression(message, valueExpression));
+            ReportAssertIsNullFailed(value, message, valueExpression);
         }
     }
 
     private static bool IsNullFailing(object? value) => value is not null;
 
-    private static void ReportAssertIsNullFailed(string? message)
-        => ReportAssertFailed("Assert.IsNull", message);
+    private static void ReportAssertIsNullFailed(object? value, string? message, string valueExpression)
+    {
+        string actualValue = AssertionValueRenderer.RenderValue(value);
+        EvidenceBlock evidence = EvidenceBlock.Create()
+            .AddLine("actual:", actualValue);
+
+        StructuredAssertionMessage structured = new(FrameworkMessages.IsNullFailedSummary);
+        structured.WithUserMessage(message);
+        structured.WithEvidence(evidence);
+        structured.WithExpectedAndActual(null, actualValue);
+        structured.WithCallSiteExpression(FormatCallSiteExpression("Assert.IsNull", valueExpression, nameof(value)));
+
+        ReportAssertFailed(structured);
+    }
 
     /// <inheritdoc cref="IsNull(object?, string, string)" />
 #pragma warning disable IDE0060 // Remove unused parameter - https://github.com/dotnet/roslyn/issues/76578
@@ -191,13 +203,20 @@ public static void IsNotNull([NotNull] object? value, string? message = "", [Cal
     {
         if (IsNotNullFailing(value))
         {
-            ReportAssertIsNotNullFailed(BuildUserMessageForValueExpression(message, valueExpression));
+            ReportAssertIsNotNullFailed(message, valueExpression);
         }
     }
 
     private static bool IsNotNullFailing([NotNullWhen(false)] object? value) => value is null;
 
     [DoesNotReturn]
-    private static void ReportAssertIsNotNullFailed(string? message)
-        => ReportAssertFailed("Assert.IsNotNull", message);
+    private static void ReportAssertIsNotNullFailed(string? message, string valueExpression)
+    {
+        // RFC: IsNotNull omits the evidence block since actual is always null
+        StructuredAssertionMessage structured = new(FrameworkMessages.IsNotNullFailedSummary);
+        structured.WithUserMessage(message);
+        structured.WithCallSiteExpression(FormatCallSiteExpression("Assert.IsNotNull", valueExpression, "value"));
+
+        ReportAssertFailed(structured);
+    }
 }

src/TestFramework/TestFramework/Assertions/Assert.IsTrue.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System.ComponentModel;
@@ -22,9 +22,11 @@ public sealed partial class Assert
     public readonly struct AssertIsTrueInterpolatedStringHandler
     {
         private readonly StringBuilder? _builder;
+        private readonly bool? _condition;
 
         public AssertIsTrueInterpolatedStringHandler(int literalLength, int formattedCount, bool? condition, out bool shouldAppend)
         {
+            _condition = condition;
             shouldAppend = IsTrueFailing(condition);
             if (shouldAppend)
             {
@@ -36,8 +38,7 @@ internal void ComputeAssertion(string conditionExpression)
         {
             if (_builder is not null)
             {
-                _builder.Insert(0, string.Format(CultureInfo.CurrentCulture, FrameworkMessages.CallerArgumentExpressionSingleParameterMessage, "condition", conditionExpression) + " ");
-                ReportAssertIsTrueFailed(_builder.ToString());
+                ReportAssertIsTrueFailed(_condition, _builder.ToString(), conditionExpression);
             }
         }
 
@@ -74,9 +75,11 @@ internal void ComputeAssertion(string conditionExpression)
     public readonly struct AssertIsFalseInterpolatedStringHandler
     {
         private readonly StringBuilder? _builder;
+        private readonly bool? _condition;
 
         public AssertIsFalseInterpolatedStringHandler(int literalLength, int formattedCount, bool? condition, out bool shouldAppend)
         {
+            _condition = condition;
             shouldAppend = IsFalseFailing(condition);
             if (shouldAppend)
             {
@@ -88,8 +91,7 @@ internal void ComputeAssertion(string conditionExpression)
         {
             if (_builder is not null)
             {
-                _builder.Insert(0, string.Format(CultureInfo.CurrentCulture, FrameworkMessages.CallerArgumentExpressionSingleParameterMessage, "condition", conditionExpression) + " ");
-                ReportAssertIsFalseFailed(_builder.ToString());
+                ReportAssertIsFalseFailed(_condition, _builder.ToString(), conditionExpression);
             }
         }
 
@@ -150,15 +152,27 @@ public static void IsTrue([DoesNotReturnIf(false)] bool? condition, string? mess
     {
         if (IsTrueFailing(condition))
         {
-            ReportAssertIsTrueFailed(BuildUserMessageForConditionExpression(message, conditionExpression));
+            ReportAssertIsTrueFailed(condition, message, conditionExpression);
         }
     }
 
     private static bool IsTrueFailing(bool? condition)
         => condition is false or null;
 
-    private static void ReportAssertIsTrueFailed(string? message)
-        => ReportAssertFailed("Assert.IsTrue", message);
+    private static void ReportAssertIsTrueFailed(bool? condition, string? message, string conditionExpression)
+    {
+        string actualValue = AssertionValueRenderer.RenderValue(condition);
+        EvidenceBlock evidence = EvidenceBlock.Create()
+            .AddLine("actual:", actualValue);
+
+        StructuredAssertionMessage structured = new(FrameworkMessages.IsTrueFailedSummary);
+        structured.WithUserMessage(message);
+        structured.WithEvidence(evidence);
+        structured.WithExpectedAndActual(null, actualValue);
+        structured.WithCallSiteExpression(FormatCallSiteExpression("Assert.IsTrue", conditionExpression, nameof(condition)));
+
+        ReportAssertFailed(structured);
+    }
 
     /// <inheritdoc cref="IsFalse(bool?, string, string)" />
 #pragma warning disable IDE0060 // Remove unused parameter - https://github.com/dotnet/roslyn/issues/76578
@@ -188,14 +202,26 @@ public static void IsFalse([DoesNotReturnIf(true)] bool? condition, string? mess
     {
         if (IsFalseFailing(condition))
         {
-            ReportAssertIsFalseFailed(BuildUserMessageForConditionExpression(message, conditionExpression));
+            ReportAssertIsFalseFailed(condition, message, conditionExpression);
         }
     }
 
     private static bool IsFalseFailing(bool? condition)
         => condition is true or null;
 
     [DoesNotReturn]
-    private static void ReportAssertIsFalseFailed(string userMessage)
-        => ReportAssertFailed("Assert.IsFalse", userMessage);
+    private static void ReportAssertIsFalseFailed(bool? condition, string? message, string conditionExpression)
+    {
+        string actualValue = AssertionValueRenderer.RenderValue(condition);
+        EvidenceBlock evidence = EvidenceBlock.Create()
+            .AddLine("actual:", actualValue);
+
+        StructuredAssertionMessage structured = new(FrameworkMessages.IsFalseFailedSummary);
+        structured.WithUserMessage(message);
+        structured.WithEvidence(evidence);
+        structured.WithExpectedAndActual(null, actualValue);
+        structured.WithCallSiteExpression(FormatCallSiteExpression("Assert.IsFalse", conditionExpression, nameof(condition)));
+
+        ReportAssertFailed(structured);
+    }
 }

src/TestFramework/TestFramework/Assertions/Assert.cs

@@ -176,6 +176,44 @@ internal static void ThrowAssertFailed(StructuredAssertionMessage structuredMess
         throw CreateAssertFailedException(structuredMessage);
     }
 
+    /// <summary>
+    /// Formats a call-site expression for display at the bottom of a structured assertion message.
+    /// When the expression is empty, the call-site is omitted. When the expression contains newlines,
+    /// it is replaced with a <c>&lt;paramName&gt;</c> placeholder.
+    /// </summary>
+    internal static string? FormatCallSiteExpression(string assertionMethodName, string expression, string paramName)
+    {
+        if (string.IsNullOrWhiteSpace(expression))
+        {
+            return null;
+        }
+
+        // If expression contains newlines (multiline constant), replace with placeholder per RFC
+        string arg = expression.Contains('\n') || expression.Contains('\r')
+            ? $"<{paramName}>"
+            : expression;
+
+        return $"{assertionMethodName}({arg})";
+    }
+
+    /// <summary>
+    /// Formats a call-site expression for display at the bottom of a structured assertion message,
+    /// using two captured expressions. When an expression contains newlines, it is replaced with a
+    /// <c>&lt;paramName&gt;</c> placeholder.
+    /// </summary>
+    internal static string? FormatCallSiteExpression(string assertionMethodName, string expression1, string paramName1, string expression2, string paramName2)
+    {
+        if (string.IsNullOrWhiteSpace(expression1) || string.IsNullOrWhiteSpace(expression2))
+        {
+            return null;
+        }
+
+        string arg1 = expression1.Contains('\n') || expression1.Contains('\r') ? $"<{paramName1}>" : expression1;
+        string arg2 = expression2.Contains('\n') || expression2.Contains('\r') ? $"<{paramName2}>" : expression2;
+
+        return $"{assertionMethodName}({arg1}, {arg2})";
+    }
+
     private static string FormatAssertionFailed(string assertionName, string? message)
     {
         string failedMessage = string.Format(CultureInfo.CurrentCulture, FrameworkMessages.AssertionFailed, assertionName);
@@ -240,9 +278,6 @@ private static string BuildUserMessageForThreeExpressions(string? format, string
             : $"{callerArgMessagePart} {userMessage}";
     }
 
-    private static string BuildUserMessageForConditionExpression(string? format, string conditionExpression)
-        => BuildUserMessageForSingleExpression(format, conditionExpression, "condition");
-
     private static string BuildUserMessageForValueExpression(string? format, string valueExpression)
         => BuildUserMessageForSingleExpression(format, valueExpression, "value");
 

src/TestFramework/TestFramework/Resources/FrameworkMessages.resx

@@ -408,4 +408,16 @@ Actual: {2}</value>
   <data name="STATestMethodNonWindowsNotSupported" xml:space="preserve">
     <value>[STATestMethod] is not supported on non-Windows platforms. STA (Single Threaded Apartment) is a Windows-only COM threading concept. Use [OSCondition(OperatingSystems.Windows)] to skip this test on non-Windows platforms.</value>
   </data>
+  <data name="IsTrueFailedSummary" xml:space="preserve">
+    <value>Expected condition to be true.</value>
+  </data>
+  <data name="IsFalseFailedSummary" xml:space="preserve">
+    <value>Expected condition to be false.</value>
+  </data>
+  <data name="IsNullFailedSummary" xml:space="preserve">
+    <value>Expected value to be null.</value>
+  </data>
+  <data name="IsNotNullFailedSummary" xml:space="preserve">
+    <value>Expected value to not be null.</value>
+  </data>
 </root>

src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.cs.xlf

@@ -272,6 +272,11 @@ Skutečnost: {2}</target>
         <target state="translated">Neplatná adresa URL lístku GitHubu</target>
         <note />
       </trans-unit>
+      <trans-unit id="IsFalseFailedSummary">
+        <source>Expected condition to be false.</source>
+        <target state="new">Expected condition to be false.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="IsInRangeFail">
         <source>Value '{0}' is not within the expected range [{1}..{2}]. {3}</source>
         <target state="translated">Hodnota {0} není v očekávaném rozsahu [{1}..{2}]. {3}</target>
@@ -317,6 +322,21 @@ Skutečnost: {2}</target>
         <target state="translated">Řetězec „{0}“ odpovídá vzoru „{1}“. {2}</target>
         <note />
       </trans-unit>
+      <trans-unit id="IsNotNullFailedSummary">
+        <source>Expected value to not be null.</source>
+        <target state="new">Expected value to not be null.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="IsNullFailedSummary">
+        <source>Expected value to be null.</source>
+        <target state="new">Expected value to be null.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="IsTrueFailedSummary">
+        <source>Expected condition to be true.</source>
+        <target state="new">Expected condition to be true.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PrivateAccessorMemberNotFound">
         <source>
       The member specified ({0}) could not be found. You might need to regenerate your private accessor,

src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.de.xlf

@@ -272,6 +272,11 @@ Tatsächlich: {2}</target>
         <target state="translated">Ungültige GitHub-Ticket-URL.</target>
         <note />
       </trans-unit>
+      <trans-unit id="IsFalseFailedSummary">
+        <source>Expected condition to be false.</source>
+        <target state="new">Expected condition to be false.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="IsInRangeFail">
         <source>Value '{0}' is not within the expected range [{1}..{2}]. {3}</source>
         <target state="translated">Der Wert „{0}“ liegt nicht im erwarteten Bereich [{1}..{2}]. {3}</target>
@@ -317,6 +322,21 @@ Tatsächlich: {2}</target>
         <target state="translated">Die Zeichenfolge „{0}“ stimmt mit dem Muster „{1}“ überein. {2}</target>
         <note />
       </trans-unit>
+      <trans-unit id="IsNotNullFailedSummary">
+        <source>Expected value to not be null.</source>
+        <target state="new">Expected value to not be null.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="IsNullFailedSummary">
+        <source>Expected value to be null.</source>
+        <target state="new">Expected value to be null.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="IsTrueFailedSummary">
+        <source>Expected condition to be true.</source>
+        <target state="new">Expected condition to be true.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PrivateAccessorMemberNotFound">
         <source>
       The member specified ({0}) could not be found. You might need to regenerate your private accessor,

src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.es.xlf

@@ -272,6 +272,11 @@ Real: {2}</target>
         <target state="translated">Dirección URL de vale de GitHub no válida</target>
         <note />
       </trans-unit>
+      <trans-unit id="IsFalseFailedSummary">
+        <source>Expected condition to be false.</source>
+        <target state="new">Expected condition to be false.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="IsInRangeFail">
         <source>Value '{0}' is not within the expected range [{1}..{2}]. {3}</source>
         <target state="translated">El valor "{0}" no está dentro del rango esperado [{1}..{2}]. {3}</target>
@@ -317,6 +322,21 @@ Real: {2}</target>
         <target state="translated">La cadena "{0}" coincide con el patrón "{1}". {2}</target>
         <note />
       </trans-unit>
+      <trans-unit id="IsNotNullFailedSummary">
+        <source>Expected value to not be null.</source>
+        <target state="new">Expected value to not be null.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="IsNullFailedSummary">
+        <source>Expected value to be null.</source>
+        <target state="new">Expected value to be null.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="IsTrueFailedSummary">
+        <source>Expected condition to be true.</source>
+        <target state="new">Expected condition to be true.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PrivateAccessorMemberNotFound">
         <source>
       The member specified ({0}) could not be found. You might need to regenerate your private accessor,