Enable nullable reference types for test project

Author: FantasyTeddy

FunctionsTests/ClientTests.cs

@@ -13,8 +13,8 @@ namespace FunctionsTests
     [TestClass]
     public class ClientTests
     {
-        Client _client;
-        string _token;
+        private Client _client = null!;
+        private string _token = null!;
 
         [TestInitialize]
         public void Initialize()

FunctionsTests/FunctionsTests.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <TargetFramework>net8.0</TargetFramework>
     <IsPackable>false</IsPackable>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>