Fix converting NUnit asserts with null as expected value (#31)

meziantou · Jan 17, 2024 · 3523b34 · 3523b34
1 parent af94ab8
commit 3523b34
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Showing 2 changed files with 80 additions and 2 deletions.
diff --git a/Meziantou.FluentAssertionsAnalyzers.Tests/NUnit4ToFluentAssertionsAnalyzerUnitTests.cs b/Meziantou.FluentAssertionsAnalyzers.Tests/NUnit4ToFluentAssertionsAnalyzerUnitTests.cs
@@ -785,4 +785,66 @@ public void MyTest()
             }
             """);
     }
+
+    [Fact]
+    public Task Assert_AreEqual_to_null()
+    {
+        return Assert(
+            """
+            using NUnit.Framework.Legacy;
+
+            class Test
+            {
+                public void MyTest()
+                {
+                    var x = System.Array.Empty<int>();
+                    [|ClassicAssert.AreEqual(null, x)|];
+                }
+            }
+            """,
+            """
+            using FluentAssertions;
+            using NUnit.Framework.Legacy;
+
+            class Test
+            {
+                public void MyTest()
+                {
+                    var x = System.Array.Empty<int>();
+                    x.Should().BeNull();
+                }
+            }
+            """);
+    }
+
+    [Fact]
+    public Task Assert_AreNotEqual_to_null()
+    {
+        return Assert(
+            """
+            using NUnit.Framework.Legacy;
+
+            class Test
+            {
+                public void MyTest()
+                {
+                    var x = System.Array.Empty<int>();
+                    [|ClassicAssert.AreNotEqual(x, null)|];
+                }
+            }
+            """,
+            """
+            using FluentAssertions;
+            using NUnit.Framework.Legacy;
+
+            class Test
+            {
+                public void MyTest()
+                {
+                    var x = System.Array.Empty<int>();
+                    x.Should().NotBeNull();
+                }
+            }
+            """);
+    }
 }
diff --git a/Meziantou.FluentAssertionsAnalyzers/NunitAssertAnalyzerCodeFixProvider.cs b/Meziantou.FluentAssertionsAnalyzers/NunitAssertAnalyzerCodeFixProvider.cs
@@ -180,7 +180,15 @@ private static async Task<Document> Rewrite(Document document, SyntaxNode nodeTo
             {
                 var (left, right) = GetLeftRight(arguments, semanticModel, cancellationToken);
                 var leftType = semanticModel.GetTypeInfo(left.Expression, cancellationToken).Type;
-                if (IsCollection(leftType))
+                if (left.Expression is LiteralExpressionSyntax { Token.Value: null })
+                {
+                    result = rewrite.UsingShould(right, "BeNull", arguments.Skip(2));
+                }
+                else if (leftType is null)
+                {
+                    // Not supported
+                }
+                else if (IsCollection(leftType))
                 {
                     result = rewrite.UsingShould(right, "Equal", ArgumentList(left, arguments.Skip(2)));
                 }
@@ -196,7 +204,15 @@ private static async Task<Document> Rewrite(Document document, SyntaxNode nodeTo
             {
                 var (left, right) = GetLeftRight(arguments, semanticModel, cancellationToken);
                 var leftType = semanticModel.GetTypeInfo(left.Expression, cancellationToken).Type;
-                if (IsCollection(leftType))
+                if (left.Expression is LiteralExpressionSyntax { Token.Value: null })
+                {
+                    result = rewrite.UsingShould(right, "NotBeNull", arguments.Skip(2));
+                }
+                else if (leftType is null)
+                {
+                    // Not supported
+                }
+                else if (IsCollection(leftType))
                 {
                     result = rewrite.UsingShould(right, "NotEqual", ArgumentList(left, arguments.Skip(2)));
                 }