diff --git a/X10D.Tests/X10D.Tests.csproj b/X10D.Tests/X10D.Tests.csproj
index f5e35bc..e5aa4d4 100644
--- a/X10D.Tests/X10D.Tests.csproj
+++ b/X10D.Tests/X10D.Tests.csproj
@@ -4,6 +4,7 @@
         <TargetFramework>net6.0</TargetFramework>
         <IsPackable>false</IsPackable>
         <Nullable>enable</Nullable>
+        <ImplicitUsings>true</ImplicitUsings>
         <EnablePreviewFeatures>True</EnablePreviewFeatures>
     </PropertyGroup>
 
diff --git a/X10D.Tests/src/Core/BooleanTests.cs b/X10D.Tests/src/Core/BooleanTests.cs
index ca6aa45..e40f133 100644
--- a/X10D.Tests/src/Core/BooleanTests.cs
+++ b/X10D.Tests/src/Core/BooleanTests.cs
@@ -1,5 +1,4 @@
-using System;
-using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
 
 namespace X10D.Tests.Core
 {
diff --git a/X10D.Tests/src/Core/IsPrimeTests.cs b/X10D.Tests/src/Core/IsPrimeTests.cs
index 0a28d5d..dfe4dab 100644
--- a/X10D.Tests/src/Core/IsPrimeTests.cs
+++ b/X10D.Tests/src/Core/IsPrimeTests.cs
@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Globalization;
-using System.IO;
-using System.Linq;
+using System.Globalization;
 using System.Reflection;
 using System.Text;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
diff --git a/X10D.Tests/src/Core/StringTests.cs b/X10D.Tests/src/Core/StringTests.cs
index 2efbb5a..32c2685 100644
--- a/X10D.Tests/src/Core/StringTests.cs
+++ b/X10D.Tests/src/Core/StringTests.cs
@@ -1,4 +1,3 @@
-using System;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
 namespace X10D.Tests.Core