Add PreferAssertFailOverAlwaysFalseConditionsAnalyzer

src/Analyzers/MSTest.Analyzers/AnalyzerReleases.Unshipped.md

@@ -11,3 +11,4 @@ MSTEST0021 | Design | Disabled | PreferDisposeOverTestCleanupAnalyzer, [Document
 MSTEST0022 | Design | Disabled | PreferTestCleanupOverDisposeAnalyzer, [Documentation](https://learn.microsoft.com/dotnet/core/testing/mstest-analyzers/mstest0022)
 MSTEST0023 | Usage | Info | DoNotNegateBooleanAssertionAnalyzer, [Documentation](https://learn.microsoft.com/dotnet/core/testing/mstest-analyzers/mstest0023)
 MSTEST0024 | Usage | Info | DoNotStoreStaticTestContextAnalyzer, [Documentation](https://learn.microsoft.com/dotnet/core/testing/mstest-analyzers/mstest0024)
+MSTEST0025 | Usage | Info | PreferAssertFailOverAlwaysFalseConditionsAnalyzer, [Documentation](https://learn.microsoft.com/dotnet/core/testing/mstest-analyzers/mstest0025)

src/Analyzers/MSTest.Analyzers/Helpers/DiagnosticIds.cs

@@ -28,4 +28,5 @@ internal static class DiagnosticIds
     public const string PreferTestCleanupOverDisposeRuleId = "MSTEST0022";
     public const string DoNotNegateBooleanAssertionRuleId = "MSTEST0023";
     public const string DoNotStoreStaticTestContextAnalyzerRuleId = "MSTEST0024";
+    public const string PreferAssertFailOverAlwaysFalseConditionsRuleId = "MSTEST0025";
 }

src/Analyzers/MSTest.Analyzers/PreferAssertFailOverAlwaysFalseConditionsAnalyzer.cs

@@ -0,0 +1,106 @@
+// 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.Collections.Immutable;
+
+using Analyzer.Utilities.Extensions;
+
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Microsoft.CodeAnalysis.Operations;
+
+using MSTest.Analyzers.Helpers;
+
+namespace MSTest.Analyzers;
+
+[DiagnosticAnalyzer(LanguageNames.CSharp, LanguageNames.VisualBasic)]
+public sealed class PreferAssertFailOverAlwaysFalseConditionsAnalyzer : DiagnosticAnalyzer
+{
+    private enum EqualityStatus
+    {
+        Unknown,
+        Equal,
+        NotEqual,
+    }
+
+    private const string ExpectedParameterName = "expected";
+    private const string NotExpectedParameterName = "notExpected";
+    private const string ActualParameterName = "actual";
+    private const string ConditionParameterName = "condition";
+    private const string ValueParameterName = "value";
+
+    private static readonly LocalizableResourceString Title = new(nameof(Resources.PreferAssertFailOverAlwaysFalseConditionsTitle), Resources.ResourceManager, typeof(Resources));
+    private static readonly LocalizableResourceString MessageFormat = new(nameof(Resources.PreferAssertFailOverAlwaysFalseConditionsMessageFormat), Resources.ResourceManager, typeof(Resources));
+
+    internal static readonly DiagnosticDescriptor Rule = DiagnosticDescriptorHelper.Create(
+        DiagnosticIds.PreferAssertFailOverAlwaysFalseConditionsRuleId,
+        Title,
+        MessageFormat,
+        null,
+        Category.Design,
+        DiagnosticSeverity.Info,
+        isEnabledByDefault: true);
+
+    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; }
+        = ImmutableArray.Create(Rule);
+
+    public override void Initialize(AnalysisContext context)
+    {
+        context.EnableConcurrentExecution();
+        context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.Analyze | GeneratedCodeAnalysisFlags.ReportDiagnostics);
+
+        context.RegisterCompilationStartAction(context =>
+        {
+            Compilation compilation = context.Compilation;
+            INamedTypeSymbol? assertSymbol = compilation.GetOrCreateTypeByMetadataName(WellKnownTypeNames.MicrosoftVisualStudioTestToolsUnitTestingAssert);
+            if (assertSymbol is not null)
+            {
+                context.RegisterOperationAction(context => AnalyzeOperation(context, assertSymbol), OperationKind.Invocation);
+            }
+        });
+    }
+
+    private static void AnalyzeOperation(OperationAnalysisContext context, INamedTypeSymbol assertSymbol)
+    {
+        var operation = (IInvocationOperation)context.Operation;
+        if (assertSymbol.Equals(operation.TargetMethod?.ContainingType, SymbolEqualityComparer.Default) &&
+            IsAlwaysFalse(operation))
+        {
+            context.ReportDiagnostic(operation.CreateDiagnostic(Rule, operation.TargetMethod.Name));
+        }
+    }
+
+    private static bool IsAlwaysFalse(IInvocationOperation operation)
+        => operation.TargetMethod.Name switch
+        {
+            "IsTrue" => GetConditionArgument(operation) is { Value.ConstantValue: { HasValue: true, Value: false } },
+            "IsFalse" => GetConditionArgument(operation) is { Value.ConstantValue: { HasValue: true, Value: true } },
+            "AreEqual" => GetEqualityStatus(operation, ExpectedParameterName) == EqualityStatus.NotEqual,
+            "AreNotEqual" => GetEqualityStatus(operation, NotExpectedParameterName) == EqualityStatus.Equal,
+            "IsNotNull" => GetValueArgument(operation) is { Value.ConstantValue: { HasValue: true, Value: null } },
+            _ => false,
+        };
+
+    private static IArgumentOperation? GetArgumentWithName(IInvocationOperation operation, string name)
+        => operation.Arguments.FirstOrDefault(arg => arg.Parameter?.Name == name);
+
+    private static IArgumentOperation? GetConditionArgument(IInvocationOperation operation)
+        => GetArgumentWithName(operation, ConditionParameterName);
+
+    private static IArgumentOperation? GetValueArgument(IInvocationOperation operation)
+        => GetArgumentWithName(operation, ValueParameterName);
+
+    private static EqualityStatus GetEqualityStatus(IInvocationOperation operation, string expectedOrNotExpectedParameterName)
+    {
+        if (GetArgumentWithName(operation, expectedOrNotExpectedParameterName) is { } expectedOrNotExpectedArgument &&
+            GetArgumentWithName(operation, ActualParameterName) is { } actualArgument &&
+            expectedOrNotExpectedArgument.Value.ConstantValue.HasValue &&
+            actualArgument.Value.ConstantValue.HasValue)
+        {
+            return Equals(expectedOrNotExpectedArgument.Value.ConstantValue.Value, actualArgument.Value.ConstantValue.Value) ? EqualityStatus.Equal : EqualityStatus.NotEqual;
+        }
+
+        // We are not sure about the equality status
+        return EqualityStatus.Unknown;
+    }
+}

src/Analyzers/MSTest.Analyzers/Resources.resx

@@ -313,6 +313,12 @@
   <data name="DoNotStoreStaticTestContextAnalyzerTitle" xml:space="preserve">
     <value>Do not store TestContext in a static member</value>
   </data>
+  <data name="PreferAssertFailOverAlwaysFalseConditionsMessageFormat" xml:space="preserve">
+    <value>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</value>
+  </data>
+  <data name="PreferAssertFailOverAlwaysFalseConditionsTitle" xml:space="preserve">
+    <value>Use 'Assert.Fail' instead of an always-failing assert</value>
+  </data>
   <data name="PreferConstructorOverTestInitializeMessageFormat" xml:space="preserve">
     <value>Prefer constructors over TestInitialize methods</value>
   </data>

src/Analyzers/MSTest.Analyzers/xlf/Resources.cs.xlf

@@ -343,6 +343,16 @@
         <target state="translated">Neukládejte TestContext ve statickém členu</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">Upřednostňovat konstruktory před metodami TestInitialize</target>

src/Analyzers/MSTest.Analyzers/xlf/Resources.de.xlf

@@ -339,6 +339,16 @@
         <target state="translated">TestContext nicht in einem statischen Member speichern</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">Konstruktoren gegenüber TestInitialize-Methoden bevorzugen</target>

src/Analyzers/MSTest.Analyzers/xlf/Resources.es.xlf

@@ -339,6 +339,16 @@
         <target state="translated">No almacenar TestContext en un miembro estático</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">Preferir constructores en lugar de métodos TestInitialize</target>

src/Analyzers/MSTest.Analyzers/xlf/Resources.fr.xlf

@@ -339,6 +339,16 @@
         <target state="translated">Ne pas stocker TestContext dans un membre statique</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">Préférer les constructeurs aux méthodes TestInitialize</target>

src/Analyzers/MSTest.Analyzers/xlf/Resources.it.xlf

@@ -339,6 +339,16 @@
         <target state="translated">Non archiviare TestContext in un membro statico</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">Preferisci costruttori rispetto ai metodi TestInitialize</target>

src/Analyzers/MSTest.Analyzers/xlf/Resources.ja.xlf

@@ -339,6 +339,16 @@
         <target state="translated">静的メンバーに TestContext を格納しない</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">TestInitialize メソッドよりもコンストラクターを優先する</target>

src/Analyzers/MSTest.Analyzers/xlf/Resources.ko.xlf

@@ -339,6 +339,16 @@
         <target state="translated">TestContext를 정적 멤버에 저장하지 마세요</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">TestInitialize 메서드보다 생성자 선호</target>

src/Analyzers/MSTest.Analyzers/xlf/Resources.pl.xlf

@@ -339,6 +339,16 @@
         <target state="translated">Nie przechowuj elementu TestContext w statycznym elemencie członkowskim</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">Preferowanie konstruktorów niż metod TestInitialize</target>

src/Analyzers/MSTest.Analyzers/xlf/Resources.pt-BR.xlf

@@ -339,6 +339,16 @@
         <target state="translated">Não armazene TestContext em um membro estático</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">Preferir construtores em vez de métodos TestInitialize</target>

src/Analyzers/MSTest.Analyzers/xlf/Resources.ru.xlf

@@ -339,6 +339,16 @@
         <target state="translated">Не хранить TestContext в статическом элементе</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">Предпочитать конструкторы методам TestInitialize</target>

src/Analyzers/MSTest.Analyzers/xlf/Resources.tr.xlf

@@ -339,6 +339,16 @@
         <target state="translated">TestContext'i statik üyede depolama</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">Oluşturucuları TestInitialize yöntemlerine tercih et</target>

src/Analyzers/MSTest.Analyzers/xlf/Resources.zh-Hans.xlf

@@ -339,6 +339,16 @@
         <target state="translated">不要将 TestContext 存储在静态成员中</target>
         <note />
       </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsMessageFormat">
+        <source>Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing 'Assert.{0}' assert</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="PreferAssertFailOverAlwaysFalseConditionsTitle">
+        <source>Use 'Assert.Fail' instead of an always-failing assert</source>
+        <target state="new">Use 'Assert.Fail' instead of an always-failing assert</target>
+        <note />
+      </trans-unit>
       <trans-unit id="PreferConstructorOverTestInitializeMessageFormat">
         <source>Prefer constructors over TestInitialize methods</source>
         <target state="translated">首选构造函数而不是 TestInitialize 方法</target>