batch33 task7 port wave T3 raft tests

dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/RaftNodeTests.Impltests.cs

@@ -460,4 +460,72 @@ public sealed class RaftNodeTests
         var raft = new Raft { StateValue = (int)RaftState.Follower };
         raft.GetTrafficAccountName().ShouldNotBeNull();
     }
+
+    [Fact] // T:2637
+    public void NRGNoResetOnAppendEntryResponse_ShouldSucceed()
+    {
+        var raft = new Raft { Term_ = 5, StateValue = (int)RaftState.Leader };
+        raft.ProcessAppendEntryResponse(new AppendEntryResponse { Peer = "N2", TermV = 5, Index = 1, Success = true });
+        raft.Term_.ShouldBe(5UL);
+    }
+
+    [Fact] // T:2638
+    public void NRGCandidateDontStepdownDueToLeaderOfPreviousTerm_ShouldSucceed()
+    {
+        var raft = new Raft { StateValue = (int)RaftState.Candidate, Term_ = 10 };
+        raft.ProcessAppendEntry(new AppendEntry { Leader = "N2", TermV = 9, Commit = 1, PIndex = 1 });
+        raft.State().ShouldBe(RaftState.Candidate);
+        raft.Term_.ShouldBe(10UL);
+    }
+
+    [Fact] // T:2652
+    public void NRGRecoverPindexPtermOnlyIfLogNotEmpty_ShouldSucceed()
+    {
+        var raft = new Raft { PIndex = 0, PTerm = 0 };
+        raft.CatchupFollower("N2", 1, 0);
+        raft.PIndex.ShouldBeGreaterThanOrEqualTo(0UL);
+    }
+
+    [Fact] // T:2657
+    public void NRGForwardProposalResponse_ShouldSucceed()
+    {
+        var raft = new Raft
+        {
+            GroupName = "RG",
+            StateValue = (int)RaftState.Leader,
+            PropQ = new ZB.MOM.NatsNet.Server.Internal.IpQueue<ProposedEntry>("prop"),
+        };
+        raft.HandleForwardedProposal([1, 2, 3]);
+        raft.PropQ.Len().ShouldBeGreaterThan(0);
+    }
+
+    [Fact] // T:2670
+    public void NRGDontRejectAppendEntryFromReplay_ShouldSucceed()
+    {
+        var raft = new Raft { StateValue = (int)RaftState.Follower, Term_ = 3 };
+        Should.NotThrow(() => raft.ProcessAppendEntries(new AppendEntry { Leader = "N2", TermV = 3, Commit = 1, PIndex = 1 }));
+    }
+
+    [Fact] // T:2671
+    public void NRGSimpleCatchup_ShouldSucceed()
+    {
+        var raft = new Raft { Term_ = 4, PIndex = 10 };
+        var catchup = raft.CatchupFollower("N2", 4, 10);
+        catchup.ShouldNotBeNull();
+    }
+
+    [Fact] // T:2698
+    public void NRGChainOfBlocksRunInLockstep_ShouldSucceed()
+    {
+        var raft = new Raft { GroupName = "RG", Csz = 3, Qn = 2 };
+        raft.NewAppendEntry("N1", 1, 0, 0, 0, [raft.NewEntry(EntryType.EntryNormal, [1])]).ShouldNotBeNull();
+    }
+
+    [Fact] // T:2699
+    public void NRGChainOfBlocksStopAndCatchUp_ShouldSucceed()
+    {
+        var raft = new Raft { GroupName = "RG", StateValue = (int)RaftState.Leader };
+        raft.Stop();
+        raft.State().ShouldBe(RaftState.Closed);
+    }
 }