Merge pull request #581 from manfred-brands/issue580_WithinOnNullable

Within is allowed on Nullable<T> when T is supported.
nunit · Sep 5, 2023 · eebf3f3 · eebf3f3
2 parents beb4407 + 908fb80
commit eebf3f3
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diff --git a/src/nunit.analyzers.tests/WithinUsage/WithinUsageAnalyzerTests.cs b/src/nunit.analyzers.tests/WithinUsage/WithinUsageAnalyzerTests.cs
@@ -272,5 +272,20 @@ public void AnalyzeOnNonGenericCollection()
 
             RoslynAssert.Valid(analyzer, testCode);
         }
+
+        [TestCase("double")]
+        [TestCase("int")]
+        [TestCase("TimeSpan")]
+        public void AnalyzeWhenAppliedToEqualityConstraintForNullableValidTypes(string type)
+        {
+            string testCode = TestUtility.WrapMethodInClassNamespaceAndAddUsings($@"
+                [TestCase(null, null)]
+                public void Test({type}? a, {type}? b)
+                {{
+                    Assert.That(a, Is.EqualTo(b).Within(0.1));
+                }}");
+
+            RoslynAssert.Valid(analyzer, testCode);
+        }
     }
 }
diff --git a/src/nunit.analyzers/WithinUsage/WithinUsageAnalyzer.cs b/src/nunit.analyzers/WithinUsage/WithinUsageAnalyzer.cs
@@ -142,6 +142,12 @@ private static bool IsTypeSupported(ITypeSymbol type, HashSet<ITypeSymbol>? chec
             if (fullName.Equals("System.DateTimeOffset", StringComparison.Ordinal))
                 return true;
 
+            // Check for Nullable<T>
+            if (fullName.Equals("System.Nullable`1", StringComparison.Ordinal))
+            {
+                return IsTypeSupported(namedType.TypeArguments[0]);
+            }
+
             if (fullName.StartsWith("System.Collections.Generic.KeyValuePair`", StringComparison.Ordinal))
             {
                 // We pass tolerance to the Value Type.