Fix sqlite null parameters + unit test

TShockAPI/Extensions/DbExt.cs

@@ -45,7 +45,7 @@ namespace TShockAPI.DB
 				{
 					com.CommandText = query;
 					for (int i = 0; i < args.Length; i++)
-						com.AddParameter("@" + i, args[i]);
+						com.AddParameter("@" + i, args[i] ?? DBNull.Value);
 					return com.ExecuteNonQuery();
 				}
 			}

TShockLauncher.Tests/GroupTests.cs

@@ -0,0 +1,50 @@
+using NUnit.Framework;
+using Terraria;
+using Terraria.Localization;
+using TShockAPI;
+using TShockAPI.DB;
+
+namespace TShockLauncher.Tests;
+
+public class GroupTests
+{
+	[SetUp]
+	public static void SetupTShock()
+	{
+		LanguageManager.Instance.SetLanguage(GameCulture.DefaultCulture);
+		Lang.InitializeLegacyLocalization();
+
+		//Setup();
+		var ts = new TShock(null); // prepares configs etc
+		ts.Initialize();
+	}
+
+	/// <summary>
+	/// This tests to ensure the group commands work.
+	/// </summary>
+	/// <remarks>Due to the switch to Microsoft.Data.Sqlite, nulls have to be replaced with DBNull for the query to complete</remarks>
+	[TestCase]
+	public void TestPermissions()
+	{
+		var groups = TShock.Groups = new GroupManager(TShock.DB);
+
+		if (!groups.GroupExists("test"))
+			groups.AddGroup("test", null, "test", Group.defaultChatColor);
+
+		groups.AddPermissions("test", new() { "abc" });
+
+		var hasperm = groups.GetGroupByName("test").Permissions.Contains("abc");
+		Assert.IsTrue(hasperm);
+
+		groups.DeletePermissions("test", new() { "abc" });
+
+		hasperm = groups.GetGroupByName("test").Permissions.Contains("abc");
+		Assert.IsFalse(hasperm);
+
+		groups.DeleteGroup("test");
+
+		var g = groups.GetGroupByName("test");
+		Assert.IsNull(g);
+	}
+}
+