diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/AbstractTypesShouldNotHaveConstructors.Records.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/AbstractTypesShouldNotHaveConstructors.Records.cs
index feecb4369f0..31f82db0694 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/AbstractTypesShouldNotHaveConstructors.Records.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/AbstractTypesShouldNotHaveConstructors.Records.cs
@@ -1,10 +1,4 @@
-// See https://github.com/dotnet/roslyn/issues/45510
-namespace System.Runtime.CompilerServices
-{
-    public class IsExternalInit { }
-}
-
-namespace Tests.Diagnostics
+namespace Tests.Diagnostics
 {
     abstract record AbstractRecordOne
     {
diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/CheckArgumentException.CSharp9.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/CheckArgumentException.CSharp9.cs
index 72445ac0ced..0d2cf7ee4aa 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/CheckArgumentException.CSharp9.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/CheckArgumentException.CSharp9.cs
@@ -1,12 +1,4 @@
-using System;
-using System.Collections.Generic;
-
-namespace System.Runtime.CompilerServices
-{
-    public class IsExternalInit { }
-}
-
-namespace Tests.Diagnostics
+namespace Tests.Diagnostics
 {
     record Program
     {
diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassNotInstantiatable.CSharp9.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassNotInstantiatable.CSharp9.cs
index 6c70e322d69..00a75847f59 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassNotInstantiatable.CSharp9.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassNotInstantiatable.CSharp9.cs
@@ -77,9 +77,3 @@ public record WithAttribute2
         private WithAttribute2() { }
     }
 }
-
-// See https://github.com/dotnet/roslyn/issues/45510
-namespace System.Runtime.CompilerServices
-{
-    public class IsExternalInit { }
-}
diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassShouldNotBeAbstract.CSharp9.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassShouldNotBeAbstract.CSharp9.cs
index 61950e2ccab..e308b3bacc1 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassShouldNotBeAbstract.CSharp9.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassShouldNotBeAbstract.CSharp9.cs
@@ -72,9 +72,3 @@ public abstract record View2 // Compliant, has abstract and non abstract members
 
     public abstract record Record(string X);
 }
-
-// See https://github.com/dotnet/roslyn/issues/45510
-namespace System.Runtime.CompilerServices
-{
-    public class IsExternalInit { }
-}
diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassWithEqualityShouldImplementIEquatable.CSharp9.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassWithEqualityShouldImplementIEquatable.CSharp9.cs
index 9b3dd34ba22..72257354017 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassWithEqualityShouldImplementIEquatable.CSharp9.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/ClassWithEqualityShouldImplementIEquatable.CSharp9.cs
@@ -15,9 +15,3 @@ public bool Equals(C other)
         return false;
     }
 }
-
-// See https://github.com/dotnet/roslyn/issues/45510
-namespace System.Runtime.CompilerServices
-{
-    public class IsExternalInit { }
-}
diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/CognitiveComplexity.CSharp9.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/CognitiveComplexity.CSharp9.cs
index 55f30a81775..301b76fd5eb 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/CognitiveComplexity.CSharp9.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/CognitiveComplexity.CSharp9.cs
@@ -105,9 +105,3 @@ static void TargetTypedConditional(bool isTrue, Apple[] apples, Fruit[] givenFru
         Fruit[] fruits3 = givenFruits ?? apples;
     }
 }
-
-// See https://github.com/dotnet/roslyn/issues/45510
-namespace System.Runtime.CompilerServices
-{
-    public class IsExternalInit { }
-}
diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/MethodName.CSharp9.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/MethodName.CSharp9.cs
index 9aa02f13f0b..3e0ff98e54b 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/MethodName.CSharp9.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/MethodName.CSharp9.cs
@@ -1,8 +1,4 @@
-namespace System.Runtime.CompilerServices
-{
-    public class IsExternalInit { }
-}
-namespace Tests.Diagnostics
+namespace Tests.Diagnostics
 {
     public interface IMyInterface
     {
diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/UnusedPrivateMember.CSharp9.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/UnusedPrivateMember.CSharp9.cs
index eef9db9fb03..c8bef5ba3d3 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/UnusedPrivateMember.CSharp9.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/UnusedPrivateMember.CSharp9.cs
@@ -63,9 +63,3 @@ static void Bar()
         { }
     }
 }
-
-// See https://github.com/dotnet/roslyn/issues/45510
-namespace System.Runtime.CompilerServices
-{
-    public class IsExternalInit { }
-}
diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/UseValueParameter.CSharp9.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/UseValueParameter.CSharp9.cs
index a32d083eea1..7f5b7c2ee12 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/UseValueParameter.CSharp9.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/UseValueParameter.CSharp9.cs
@@ -21,9 +21,3 @@ public int this[int i]
         }
     }
 }
-
-// See https://github.com/dotnet/roslyn/issues/45510
-namespace System.Runtime.CompilerServices
-{
-    public class IsExternalInit { }
-}
diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/VariableUnused.CSharp9.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/VariableUnused.CSharp9.cs
index 1f2aeec2010..e6ac6e71c2a 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/VariableUnused.CSharp9.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestCases/VariableUnused.CSharp9.cs
@@ -27,9 +27,3 @@ void Method()
         string unusedString = string.Empty; // Noncompliant
     }
 }
-
-// See https://github.com/dotnet/roslyn/issues/45510
-namespace System.Runtime.CompilerServices
-{
-    public class IsExternalInit { }
-}
diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestFramework/SolutionBuilder.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestFramework/SolutionBuilder.cs
index ee0db5ccae0..59bed837e13 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestFramework/SolutionBuilder.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestFramework/SolutionBuilder.cs
@@ -32,6 +32,7 @@ namespace SonarAnalyzer.UnitTest.TestFramework
     internal struct SolutionBuilder
     {
         private const string GeneratedAssemblyName = "project";
+        private const string InitSnippet = @"namespace System.Runtime.CompilerServices { public class IsExternalInit { } } // See https://github.com/dotnet/roslyn/issues/45510";
 
         private Solution Solution { get; }
 
@@ -89,8 +90,9 @@ public static SolutionBuilder Create() =>
             FromSolution(new AdhocWorkspace().CurrentSolution);
 
         public static SolutionBuilder CreateSolutionFromPaths(IEnumerable<string> paths,
-            OutputKind outputKind = OutputKind.DynamicallyLinkedLibrary,
-            IEnumerable<MetadataReference> additionalReferences = null)
+                                                              OutputKind outputKind = OutputKind.DynamicallyLinkedLibrary,
+                                                              IEnumerable<MetadataReference> additionalReferences = null,
+                                                              bool isSupportForCSharp9InitNeeded = false)
         {
             if (paths == null ||
                 !paths.Any())
@@ -109,6 +111,11 @@ public static SolutionBuilder CreateSolutionFromPaths(IEnumerable<string> paths,
                 .AddDocuments(paths)
                 .AddReferences(additionalReferences);
 
+            if (isSupportForCSharp9InitNeeded)
+            {
+                project = project.AddSnippet(InitSnippet);
+            }
+
             if (additionalReferences != null &&
                 additionalReferences.Any(r => r.Display.Contains("\\netstandard")))
             {
diff --git a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestFramework/Verifier.cs b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestFramework/Verifier.cs
index 0dcd059d4ee..db01aea4d71 100644
--- a/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestFramework/Verifier.cs
+++ b/sonaranalyzer-dotnet/tests/SonarAnalyzer.UnitTest/TestFramework/Verifier.cs
@@ -141,7 +141,7 @@ private static void VerifyAnalyzer(IEnumerable<string> paths, SonarDiagnosticAna
             OutputKind outputKind = OutputKind.DynamicallyLinkedLibrary,
             IEnumerable<MetadataReference> additionalReferences = null)
         {
-            var solutionBuilder = SolutionBuilder.CreateSolutionFromPaths(paths, outputKind, additionalReferences);
+            var solutionBuilder = SolutionBuilder.CreateSolutionFromPaths(paths, outputKind, additionalReferences, IsSupportForCSharp9InitNeeded(options));
 
             foreach (var compilation in solutionBuilder.Compile(options?.ToArray()))
             {
@@ -206,5 +206,9 @@ public static void VerifyCodeFix(string path, string pathToExpected,
         {
             CodeFixVerifier.VerifyCodeFix(path, pathToExpected, pathToExpected, diagnosticAnalyzer, codeFixProvider, codeFixTitle, options, additionalReferences);
         }
+
+        private static bool IsSupportForCSharp9InitNeeded(IEnumerable<ParseOptions> options) =>
+            options != null
+            && options.OfType<CSharpParseOptions>().Select(option => option.LanguageVersion).Contains(LanguageVersion.CSharp9);
     }
 }