raft: add test for maybeappend change

raft/raft_test.go

@@ -498,8 +498,10 @@ func TestHandleMsgApp(t *testing.T) {
 		{pb.Message{Type: msgApp, Term: 2, LogTerm: 1, Index: 1, Commit: 4, Entries: []pb.Entry{{Term: 2}}}, 2, 2, false},
 
 		// Ensure 3
-		{pb.Message{Type: msgApp, Term: 2, LogTerm: 2, Index: 2, Commit: 2}, 2, 2, false},
-		{pb.Message{Type: msgApp, Term: 2, LogTerm: 2, Index: 2, Commit: 4}, 2, 2, false}, // commit upto min(commit, last)
+		{pb.Message{Type: msgApp, Term: 1, LogTerm: 1, Index: 1, Commit: 3}, 2, 1, false},                                 // match entry 1, commit upto last new entry 1
+		{pb.Message{Type: msgApp, Term: 1, LogTerm: 1, Index: 1, Commit: 3, Entries: []pb.Entry{{Term: 2}}}, 2, 2, false}, // match entry 1, commit upto last new entry 2
+		{pb.Message{Type: msgApp, Term: 2, LogTerm: 2, Index: 2, Commit: 3}, 2, 2, false},                                 // match entry 2, commit upto last new entry 2
+		{pb.Message{Type: msgApp, Term: 2, LogTerm: 2, Index: 2, Commit: 4}, 2, 2, false},                                 // commit upto log.last()
 	}
 
 	for i, tt := range tests {