[ADDED] TLS connection rate limiter

server/rate_counter_test.go

@@ -0,0 +1,52 @@
+// Copyright 2021-2022 The NATS Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package server
+
+import (
+	"testing"
+	"time"
+)
+
+func TestRateCounter(t *testing.T) {
+	counter := newRateCounter(10)
+	counter.interval = 100 * time.Millisecond
+
+	var i int
+	for i = 0; i < 10; i++ {
+		if !counter.allow() {
+			t.Errorf("counter should allow (iteration %d)", i)
+		}
+	}
+	for i = 0; i < 5; i++ {
+		if counter.allow() {
+			t.Errorf("counter should not allow (iteration %d)", i)
+		}
+	}
+
+	blocked := counter.countBlocked()
+	if blocked != 5 {
+		t.Errorf("Expected blocked = 5, got %d", blocked)
+	}
+
+	blocked = counter.countBlocked()
+	if blocked != 0 {
+		t.Errorf("Expected blocked = 0, got %d", blocked)
+	}
+
+	time.Sleep(150 * time.Millisecond)
+
+	if !counter.allow() {
+		t.Errorf("Expected true after current time window expired")
+	}
+}