add support for xunit StringAsserts Equals (#229)

Author: Meir017

src/FluentAssertions.Analyzers.Tests/Tips/XunitTests.cs

@@ -214,6 +214,20 @@ public void AssertObjectEqualWithComparer_TestCodeFix(string oldAssertion, strin
         public void AssertObjectEqual_TestCodeFix(string oldAssertion, string newAssertion)
             => VerifyCSharpFix<AssertEqualCodeFix, AssertEqualAnalyzer>("object actual, object expected", oldAssertion, newAssertion);
 
+        [DataTestMethod]
+        [DataRow("Assert.Equal(expected, actual);")]
+        [Implemented]
+        public void AssertStringEqual_TestAnalyzer(string assertion) =>
+            VerifyCSharpDiagnostic<AssertEqualAnalyzer>("string actual, string expected", assertion);
+
+        [DataTestMethod]
+        [DataRow(
+            /* oldAssertion: */ "Assert.Equal(expected, actual);",
+            /* newAssertion: */ "actual.Should().Be(expected);")]
+        [Implemented]
+        public void AssertStringEqual_TestCodeFix(string oldAssertion, string newAssertion)
+            => VerifyCSharpFix<AssertEqualCodeFix, AssertEqualAnalyzer>("string actual, string expected", oldAssertion, newAssertion);
+
         [DataTestMethod]
         [DataRow("Assert.StrictEqual(expected, actual);")]
         [Implemented]

src/FluentAssertions.Analyzers/Tips/Xunit/AssertEqual.cs

@@ -22,6 +22,7 @@ public class AssertEqualAnalyzer : XunitAnalyzer
     protected override DiagnosticDescriptor Rule => new(DiagnosticId, Title, Message, Category, DiagnosticSeverity.Info, true);
     protected override IEnumerable<FluentAssertionsCSharpSyntaxVisitor> Visitors => new FluentAssertionsCSharpSyntaxVisitor[]
     {
+        new AssertStringEqualSyntaxVisitor(),
         new AssertFloatEqualWithToleranceSyntaxVisitor(),
         new AssertDoubleEqualWithToleranceSyntaxVisitor(),
         new AssertDoubleEqualWithPrecisionSyntaxVisitor(),
@@ -30,7 +31,18 @@ public class AssertEqualAnalyzer : XunitAnalyzer
         new AssertObjectEqualWithComparerSyntaxVisitor(),
         new AssertObjectEqualSyntaxVisitor()
     };
-    
+
+    // public static void Equal(string? expected, string? actual)
+    public class AssertStringEqualSyntaxVisitor : FluentAssertionsCSharpSyntaxVisitor
+    {
+        public AssertStringEqualSyntaxVisitor() : base(
+            MemberValidator.ArgumentsMatch("Equal", 
+                ArgumentValidator.IsType(TypeSelector.GetStringType), 
+                ArgumentValidator.IsType(TypeSelector.GetStringType)))
+        {
+        }
+    }
+
     // public static void Equal(float expected, float actual, float tolerance)
     public class AssertFloatEqualWithToleranceSyntaxVisitor : FluentAssertionsCSharpSyntaxVisitor
     {
@@ -137,6 +149,7 @@ protected override ExpressionSyntax GetNewExpression(
             case nameof(AssertEqualAnalyzer.AssertDateTimeEqualSyntaxVisitor):
                 return RenameMethodAndReorderActualExpectedAndReplaceWithSubjectShould(expression, "Equal", "BeCloseTo");
             case nameof(AssertEqualAnalyzer.AssertObjectEqualSyntaxVisitor):
+            case nameof(AssertEqualAnalyzer.AssertStringEqualSyntaxVisitor):
                 return RenameMethodAndReorderActualExpectedAndReplaceWithSubjectShould(expression, "Equal", "Be");
             default:
                 throw new System.InvalidOperationException($"Invalid visitor name - {properties.VisitorName}");