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// Copyright 2019 The gVisor 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 eventchannel
import (
"fmt"
"testing"
"time"
"github.com/golang/protobuf/proto"
"gvisor.dev/gvisor/pkg/sync"
)
// testEmitter is an emitter that can be used in tests. It records all events
// emitted, and whether it has been closed.
type testEmitter struct {
// mu protects all fields below.
mu sync.Mutex
// events contains all emitted events.
events []proto.Message
// closed records whether Close() was called.
closed bool
}
// Emit implements Emitter.Emit.
func (te *testEmitter) Emit(msg proto.Message) (bool, error) {
te.mu.Lock()
defer te.mu.Unlock()
te.events = append(te.events, msg)
return false, nil
}
// Close implements Emitter.Close.
func (te *testEmitter) Close() error {
te.mu.Lock()
defer te.mu.Unlock()
if te.closed {
return fmt.Errorf("closed called twice")
}
te.closed = true
return nil
}
// testMessage implements proto.Message for testing.
type testMessage struct {
proto.Message
// name is the name of the message, used by tests to compare messages.
name string
}
func TestMultiEmitter(t *testing.T) {
// Create three testEmitters, tied together in a multiEmitter.
me := &multiEmitter{}
var emitters []*testEmitter
for i := 0; i < 3; i++ {
te := &testEmitter{}
emitters = append(emitters, te)
me.AddEmitter(te)
}
// Emit three messages to multiEmitter.
names := []string{"foo", "bar", "baz"}
for _, name := range names {
m := testMessage{name: name}
if _, err := me.Emit(m); err != nil {
t.Fatalf("me.Emit(%v) failed: %v", m, err)
}
}
// All three emitters should have all three events.
for _, te := range emitters {
if got, want := len(te.events), len(names); got != want {
t.Fatalf("emitter got %d events, want %d", got, want)
}
for i, name := range names {
if got := te.events[i].(testMessage).name; got != name {
t.Errorf("emitter got message with name %q, want %q", got, name)
}
}
}
// Close multiEmitter.
if err := me.Close(); err != nil {
t.Fatalf("me.Close() failed: %v", err)
}
// All testEmitters should be closed.
for _, te := range emitters {
if !te.closed {
t.Errorf("te.closed got false, want true")
}
}
}
func TestRateLimitedEmitter(t *testing.T) {
// Create a RateLimittedEmitter that wraps a testEmitter.
te := &testEmitter{}
max := float64(5) // events per second
burst := 10 // events
rle := RateLimitedEmitterFrom(te, max, burst)
// Send 50 messages in one shot.
for i := 0; i < 50; i++ {
if _, err := rle.Emit(testMessage{}); err != nil {
t.Fatalf("rle.Emit failed: %v", err)
}
}
// We should have received only 10 messages.
if got, want := len(te.events), 10; got != want {
t.Errorf("got %d events, want %d", got, want)
}
// Sleep for a second and then send another 50.
time.Sleep(1 * time.Second)
for i := 0; i < 50; i++ {
if _, err := rle.Emit(testMessage{}); err != nil {
t.Fatalf("rle.Emit failed: %v", err)
}
}
// We should have at least 5 more message, plus maybe a few more if the
// test ran slowly.
got, wantAtLeast, wantAtMost := len(te.events), 15, 20
if got < wantAtLeast {
t.Errorf("got %d events, want at least %d", got, wantAtLeast)
}
if got > wantAtMost {
t.Errorf("got %d events, want at most %d", got, wantAtMost)
}
}
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