From 4bdd826a78a4d1f6dff36debd149c56fe7ab6086 Mon Sep 17 00:00:00 2001
From: Julien Richard <julien.richard@ubisoft.com>
Date: Fri, 8 Dec 2023 10:13:52 +0100
Subject: [PATCH 1/3] Detect & fix inverted NUnit asserts

---
 ...nit4ToFluentAssertionsAnalyzerUnitTests.cs | 64 +++++++++++++++++++
 .../NunitAssertAnalyzerCodeFixProvider.cs     | 39 ++++++++---
 2 files changed, 94 insertions(+), 9 deletions(-)

diff --git a/Meziantou.FluentAssertionsAnalyzers.Tests/NUnit4ToFluentAssertionsAnalyzerUnitTests.cs b/Meziantou.FluentAssertionsAnalyzers.Tests/NUnit4ToFluentAssertionsAnalyzerUnitTests.cs
index 33d6f42..6e1a87a 100644
--- a/Meziantou.FluentAssertionsAnalyzers.Tests/NUnit4ToFluentAssertionsAnalyzerUnitTests.cs
+++ b/Meziantou.FluentAssertionsAnalyzers.Tests/NUnit4ToFluentAssertionsAnalyzerUnitTests.cs
@@ -564,4 +564,68 @@ public void MyTest()
               }
               """);
     }
+
+    [Theory]
+    [InlineData(@"ClassicAssert.AreEqual(test, 6)", @"test.Should().Be(6)")]
+    [InlineData(@"ClassicAssert.AreNotEqual(test, 6)", @"test.Should().NotBe(6)")]
+    [InlineData(@"ClassicAssert.AreEqual(test, ""test"")", @"test.Should().Be(""test"")")]
+    [InlineData(@"ClassicAssert.AreNotEqual(test, ""test"")", @"test.Should().NotBe(""test"")")]
+    public Task Assert_Inverted_Asserts(string code, string fix)
+    {
+        return Assert(
+            $$"""
+              using NUnit.Framework.Legacy;
+
+              class Test
+              {
+                  public void MyTest(object test)
+                  {
+                      [|{{code}}|];
+                  }
+              }
+              """,
+            $$"""
+              using FluentAssertions;
+              using NUnit.Framework.Legacy;
+
+              class Test
+              {
+                  public void MyTest(object test)
+                  {
+                      {{fix}};
+                  }
+              }
+              """);
+    }
+
+    [Theory]
+    [InlineData(@"ClassicAssert.AreEqual(test, 6.0, delta: 2.0)", @"test.Should().BeApproximately(6.0, 2.0)")]
+    [InlineData(@"ClassicAssert.AreEqual(test, 6.0)", @"test.Should().Be(6.0)")]
+    public Task Assert_Inverted_Asserts_double(string code, string fix)
+    {
+        return Assert(
+            $$"""
+              using NUnit.Framework.Legacy;
+
+              class Test
+              {
+                  public void MyTest(double test)
+                  {
+                      [|{{code}}|];
+                  }
+              }
+              """,
+            $$"""
+              using FluentAssertions;
+              using NUnit.Framework.Legacy;
+
+              class Test
+              {
+                  public void MyTest(double test)
+                  {
+                      {{fix}};
+                  }
+              }
+              """);
+    }
 }
diff --git a/Meziantou.FluentAssertionsAnalyzers/NunitAssertAnalyzerCodeFixProvider.cs b/Meziantou.FluentAssertionsAnalyzers/NunitAssertAnalyzerCodeFixProvider.cs
index ba81352..18b4f49 100644
--- a/Meziantou.FluentAssertionsAnalyzers/NunitAssertAnalyzerCodeFixProvider.cs
+++ b/Meziantou.FluentAssertionsAnalyzers/NunitAssertAnalyzerCodeFixProvider.cs
@@ -178,18 +178,17 @@ private static async Task<Document> Rewrite(Document document, SyntaxNode nodeTo
         {
             if (methodName is "AreEqual")
             {
-                if (method.Parameters[0].Type.SpecialType == SpecialType.System_Double)
-                {
-                    result = rewrite.UsingShould(arguments[1], "BeApproximately", ArgumentList(arguments[0], arguments.Skip(2)));
-                }
-                else
-                {
-                    result = rewrite.UsingShould(arguments[1], "Be", ArgumentList(arguments[0], arguments.Skip(2)));
-                }
+                var (left, right) = GetLeftRight(arguments, semanticModel, cancellationToken);
+                
+                var useBeApproximately = semanticModel.GetTypeInfo(left.Expression, cancellationToken).Type?.SpecialType == SpecialType.System_Double 
+                    && arguments.FirstOrDefault(x => x.NameColon?.Name.Identifier.ValueText is "delta") is not null;
+                
+                result = rewrite.UsingShould(right, useBeApproximately ? "BeApproximately" : "Be", ArgumentList(left, arguments.Skip(2)));
             }
             else if (methodName is "AreNotEqual")
             {
-                result = rewrite.UsingShould(arguments[1], "NotBe", ArgumentList(arguments[0], arguments.Skip(2)));
+                var (left, right) = GetLeftRight(arguments, semanticModel, cancellationToken);
+                result = rewrite.UsingShould(right, "NotBe", ArgumentList(left, arguments.Skip(2)));
             }
             else if (methodName is "AreSame")
             {
@@ -855,6 +854,28 @@ bool IsGenericMethod(out ITypeSymbol typeArgument, ITypeSymbol root, params stri
         return document;
     }
 
+    private static (ArgumentSyntax left, ArgumentSyntax right) GetLeftRight(SeparatedSyntaxList<ArgumentSyntax> arguments, SemanticModel semanticModel, CancellationToken cancellationToken)
+    {
+        var left = arguments[0];
+        var right = arguments[1];
+        var leftValue = semanticModel.GetConstantValue(left.Expression, cancellationToken);
+        var rightValue = semanticModel.GetConstantValue(right.Expression, cancellationToken);
+        
+        // Don't invert if both are constant
+        if (leftValue.HasValue && rightValue.HasValue)
+        {
+            return (left, right);
+        }
+        
+        // Invert if right is constant
+        if (rightValue.HasValue)
+        {
+            return (right, left);
+        }
+
+        return (left, right);
+    }
+
     private static ITypeSymbol GetConstantTypeValue(SemanticModel semanticModel, ExpressionSyntax expression, CancellationToken cancellationToken)
     {
         var operation = semanticModel.GetOperation(expression, cancellationToken);

From 2dca43e7bd1492904fb1ace3534c4999e466cc95 Mon Sep 17 00:00:00 2001
From: Julien Richard <julien.richard@ubisoft.com>
Date: Fri, 8 Dec 2023 15:53:07 +0100
Subject: [PATCH 2/3] Update Meziantou.FluentAssertionsAnalyzers.csproj

---
 .../Meziantou.FluentAssertionsAnalyzers.csproj                | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Meziantou.FluentAssertionsAnalyzers/Meziantou.FluentAssertionsAnalyzers.csproj b/Meziantou.FluentAssertionsAnalyzers/Meziantou.FluentAssertionsAnalyzers.csproj
index c69d875..1883992 100644
--- a/Meziantou.FluentAssertionsAnalyzers/Meziantou.FluentAssertionsAnalyzers.csproj
+++ b/Meziantou.FluentAssertionsAnalyzers/Meziantou.FluentAssertionsAnalyzers.csproj
@@ -1,8 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0</TargetFrameworks>
-    <Version>1.0.14</Version>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <Version>1.0.15</Version>
     <IncludeBuildOutput>false</IncludeBuildOutput>
     <developmentDependency>true</developmentDependency>
     <Description>A Roslyn analyzer to help migrate from Xunit / NUnit assertions to FluentAssertions</Description>

From 8931491b2dab1446dab2d71404011da2491870e7 Mon Sep 17 00:00:00 2001
From: Julien Richard <julien.richard@ubisoft.com>
Date: Fri, 8 Dec 2023 15:55:58 +0100
Subject: [PATCH 3/3] Update Meziantou.FluentAssertionsAnalyzers.csproj

---
 .../Meziantou.FluentAssertionsAnalyzers.csproj                  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Meziantou.FluentAssertionsAnalyzers/Meziantou.FluentAssertionsAnalyzers.csproj b/Meziantou.FluentAssertionsAnalyzers/Meziantou.FluentAssertionsAnalyzers.csproj
index 1883992..a200fc1 100644
--- a/Meziantou.FluentAssertionsAnalyzers/Meziantou.FluentAssertionsAnalyzers.csproj
+++ b/Meziantou.FluentAssertionsAnalyzers/Meziantou.FluentAssertionsAnalyzers.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFrameworks>netstandard2.0</TargetFrameworks>
     <Version>1.0.15</Version>
     <IncludeBuildOutput>false</IncludeBuildOutput>
     <developmentDependency>true</developmentDependency>