snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

balancer/rls/internal/adaptive/lookback_test.go

@@ -0,0 +1,85 @@
+/*
+ *
+ * Copyright 2020 gRPC 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 adaptive
+
+import (
+	"testing"
+	"time"
+)
+
+func TestLookback(t *testing.T) {
+	makeTicks := func(offsets []int64) []time.Time {
+		var ticks []time.Time
+		now := time.Now()
+		for _, offset := range offsets {
+			ticks = append(ticks, now.Add(time.Duration(offset)))
+		}
+		return ticks
+	}
+
+	// lookback.add and lookback.sum behave correctly.
+	testcases := []struct {
+		desc   string
+		bins   int64
+		ticks  []time.Time
+		values []int64
+		want   []int64
+	}{
+		{
+			"Accumulate",
+			3,
+			makeTicks([]int64{0, 1, 2}), // Ticks
+			[]int64{1, 2, 3},            // Values
+			[]int64{1, 3, 6},            // Want
+		},
+		{
+			"LightTimeTravel",
+			3,
+			makeTicks([]int64{1, 0, 2}), // Ticks
+			[]int64{1, 2, 3},            // Values
+			[]int64{1, 3, 6},            // Want
+		},
+		{
+			"HeavyTimeTravel",
+			3,
+			makeTicks([]int64{8, 0, 9}), // Ticks
+			[]int64{1, 2, 3},            // Values
+			[]int64{1, 1, 4},            // Want
+		},
+		{
+			"Rollover",
+			1,
+			makeTicks([]int64{0, 1, 2}), // Ticks
+			[]int64{1, 2, 3},            // Values
+			[]int64{1, 2, 3},            // Want
+		},
+	}
+
+	for _, test := range testcases {
+		t.Run(test.desc, func(t *testing.T) {
+			lb := newLookback(test.bins, time.Duration(test.bins))
+			for i, tick := range test.ticks {
+				lb.add(tick, test.values[i])
+				if got := lb.sum(tick); got != test.want[i] {
+					t.Errorf("sum for index %d got %d, want %d", i, got, test.want[i])
+				}
+			}
+		})
+	}
+}