| /* |
| * Copyright 2019 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 edsbalancer |
| |
| import ( |
| "sync" |
| "testing" |
| |
| "google.golang.org/grpc/balancer/internal/wrr" |
| ) |
| |
| // testWRR is a deterministic WRR implementation. |
| // |
| // The real implementation does random WRR. testWRR makes the balancer behavior |
| // deterministic and easier to test. |
| // |
| // With {a: 2, b: 3}, the Next() results will be {a, a, b, b, b}. |
| type testWRR struct { |
| itemsWithWeight []struct { |
| item interface{} |
| weight int64 |
| } |
| length int |
| |
| mu sync.Mutex |
| idx int // The index of the item that will be picked |
| count int64 // The number of times the current item has been picked. |
| } |
| |
| func newTestWRR() wrr.WRR { |
| return &testWRR{} |
| } |
| |
| func (twrr *testWRR) Add(item interface{}, weight int64) { |
| twrr.itemsWithWeight = append(twrr.itemsWithWeight, struct { |
| item interface{} |
| weight int64 |
| }{item: item, weight: weight}) |
| twrr.length++ |
| } |
| |
| func (twrr *testWRR) Next() interface{} { |
| twrr.mu.Lock() |
| iww := twrr.itemsWithWeight[twrr.idx] |
| twrr.count++ |
| if twrr.count >= iww.weight { |
| twrr.idx = (twrr.idx + 1) % twrr.length |
| twrr.count = 0 |
| } |
| twrr.mu.Unlock() |
| return iww.item |
| } |
| |
| func init() { |
| newRandomWRR = newTestWRR |
| } |
| |
| func TestDropper(t *testing.T) { |
| const repeat = 2 |
| |
| type args struct { |
| numerator uint32 |
| denominator uint32 |
| } |
| tests := []struct { |
| name string |
| args args |
| }{ |
| { |
| name: "2_3", |
| args: args{ |
| numerator: 2, |
| denominator: 3, |
| }, |
| }, |
| { |
| name: "4_8", |
| args: args{ |
| numerator: 4, |
| denominator: 8, |
| }, |
| }, |
| { |
| name: "7_20", |
| args: args{ |
| numerator: 7, |
| denominator: 20, |
| }, |
| }, |
| } |
| for _, tt := range tests { |
| t.Run(tt.name, func(t *testing.T) { |
| d := newDropper(tt.args.numerator, tt.args.denominator, "") |
| var ( |
| dCount int |
| wantCount = int(tt.args.numerator) * repeat |
| loopCount = int(tt.args.denominator) * repeat |
| ) |
| for i := 0; i < loopCount; i++ { |
| if d.drop() { |
| dCount++ |
| } |
| } |
| |
| if dCount != (wantCount) { |
| t.Errorf("with numerator %v, denominator %v repeat %v, got drop count: %v, want %v", |
| tt.args.numerator, tt.args.denominator, repeat, dCount, wantCount) |
| } |
| }) |
| } |
| } |