Add test for soft cap (#10627)

Content.IntegrationTests/Tests/Lobby/ServerReloginTest.cs

@@ -1,6 +1,68 @@
+using System.Linq;
+using System.Threading.Tasks;
+using Content.Shared.CCVar;
+using NUnit.Framework;
+using Robust.Server.Player;
+using Robust.Shared.Configuration;
+using Robust.Shared.IoC;
+using Robust.Shared.Network;
 namespace Content.IntegrationTests.Tests.Lobby;
 
 public class ServerReloginTest
 {
-    
+    [Test]
+    public async Task Relogin()
+    {
+        IConfigurationManager serverConfig = default;
+        IPlayerManager serverPlayerMgr = default;
+        IClientNetManager clientNetManager = default;
+        await using var pairTracker = await PoolManager.GetServerClient();
+        var server = pairTracker.Pair.Server;
+        var client = pairTracker.Pair.Client;
+        int originalMaxPlayers = 0;
+        string username = null;
+        await server.WaitAssertion(() =>
+        {
+            serverConfig = IoCManager.Resolve<IConfigurationManager>();
+            serverPlayerMgr = IoCManager.Resolve<IPlayerManager>();
+            Assert.That(serverPlayerMgr.PlayerCount, Is.EqualTo(1));
+            originalMaxPlayers = serverConfig.GetCVar(CCVars.SoftMaxPlayers);
+            username = serverPlayerMgr.Sessions.First().Name;
+
+            //No new players are allowed, but since our client was already playing, they should be able to get in
+            serverConfig.SetCVar(CCVars.SoftMaxPlayers, 0);
+        });
+
+        await client.WaitAssertion(() =>
+        {
+            clientNetManager = IoCManager.Resolve<IClientNetManager>();
+            clientNetManager.ClientDisconnect("For testing");
+        });
+
+        await PoolManager.RunTicksSync(pairTracker.Pair, 20);
+
+        await server.WaitAssertion(() =>
+        {
+            Assert.That(serverPlayerMgr.PlayerCount, Is.EqualTo(0));
+        });
+        client.SetConnectTarget(server);
+        await client.WaitPost(() =>
+        {
+            clientNetManager.ClientConnect(null!, 0, username);
+        });
+
+        await PoolManager.RunTicksSync(pairTracker.Pair, 20);
+
+        await server.WaitAssertion(() =>
+        {
+
+            // Check that we were able to reconnect
+            Assert.That(serverPlayerMgr.PlayerCount, Is.EqualTo(1));
+
+            //Put the cvar back, so other tests can still use this server
+            serverConfig.SetCVar(CCVars.SoftMaxPlayers, originalMaxPlayers);
+        });
+
+        await pairTracker.CleanReturnAsync();
+    }
 }