Add tests for Unity custom serializable class

analyzers/tests/SonarAnalyzer.Test/Rules/FieldsShouldBeEncapsulatedInPropertiesTest.cs

@@ -36,7 +36,7 @@ public void FieldsShouldBeEncapsulatedInProperties_Unity3D_Ignored() =>
         builder.AddPaths("FieldsShouldBeEncapsulatedInProperties.Unity3D.cs")
             // Concurrent analysis puts fake Unity3D class into the Concurrent namespace
             .WithConcurrentAnalysis(false)
-            .VerifyNoIssues();
+            .Verify();
 
 #if NET
 

analyzers/tests/SonarAnalyzer.Test/TestCases/FieldsShouldBeEncapsulatedInProperties.Unity3D.cs

@@ -1,4 +1,6 @@
-// https://github.com/SonarSource/sonar-dotnet/issues/7522
+using System;
+
+// https://github.com/SonarSource/sonar-dotnet/issues/7522
 public class UnityMonoBehaviour : UnityEngine.MonoBehaviour
 {
     public int Field1; // Compliant
@@ -9,10 +11,22 @@ public class UnityScriptableObject : UnityEngine.ScriptableObject
     public int Field1; // Compliant
 }
 
+public class InvalidCustomSerializableClass1 : UnityEngine.Object
+{
+    public int Field1; // Noncompliant
+}
+
+[Serializable]
+public class ValidCustomSerializableClass : UnityEngine.Object
+{
+    public int Field1; // Compliant
+}
+
 // Unity3D does not seem to be available as a nuget package and we cannot use the original classes
 // Cannot run this test case in Concurrent mode because of the Concurrent namespace
 namespace UnityEngine
 {
     public class MonoBehaviour { }
     public class ScriptableObject { }
+    public class Object { }
 }