tailscale/net/netmon/loghelper_test.go
Claus Lensbøl ce752b8a88
net/netmon: remove usage of direct callbacks from netmon (#17292)
The callback itself is not removed as it is used in other repos, making
it simpler for those to slowly transition to the eventbus.

Updates #15160

Signed-off-by: Claus Lensbøl <claus@tailscale.com>
2025-10-01 14:59:38 -04:00

87 lines
2.2 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package netmon
import (
"bytes"
"context"
"fmt"
"testing"
"testing/synctest"
"tailscale.com/util/eventbus"
"tailscale.com/util/eventbus/eventbustest"
)
func TestLinkChangeLogLimiter(t *testing.T) { synctest.Test(t, syncTestLinkChangeLogLimiter) }
func syncTestLinkChangeLogLimiter(t *testing.T) {
bus := eventbus.New()
defer bus.Close()
mon, err := New(bus, t.Logf)
if err != nil {
t.Fatal(err)
}
defer mon.Close()
var logBuffer bytes.Buffer
logf := func(format string, args ...any) {
t.Logf("captured log: "+format, args...)
if format[len(format)-1] != '\n' {
format += "\n"
}
fmt.Fprintf(&logBuffer, format, args...)
}
ctx, cancel := context.WithCancel(t.Context())
defer cancel()
logf = LinkChangeLogLimiter(ctx, logf, mon)
// Log once, which should write to our log buffer.
logf("hello %s", "world")
if got := logBuffer.String(); got != "hello world\n" {
t.Errorf("unexpected log buffer contents: %q", got)
}
// Log again, which should not write to our log buffer.
logf("hello %s", "andrew")
if got := logBuffer.String(); got != "hello world\n" {
t.Errorf("unexpected log buffer contents: %q", got)
}
// Log a different message, which should write to our log buffer.
logf("other message")
if got := logBuffer.String(); got != "hello world\nother message\n" {
t.Errorf("unexpected log buffer contents: %q", got)
}
// Synthesize a fake major change event, which should clear the format
// string cache and allow the next log to write to our log buffer.
//
// InjectEvent doesn't work because it's not a major event, so we
// instead inject the event ourselves.
injector := eventbustest.NewInjector(t, bus)
eventbustest.Inject(injector, ChangeDelta{Major: true})
synctest.Wait()
logf("hello %s", "world")
want := "hello world\nother message\nhello world\n"
if got := logBuffer.String(); got != want {
t.Errorf("unexpected log buffer contents, got: %q, want, %q", got, want)
}
// Canceling the context we passed to LinkChangeLogLimiter should
// unregister the callback from the netmon.
cancel()
synctest.Wait()
mon.mu.Lock()
if len(mon.cbs) != 0 {
t.Errorf("expected no callbacks, got %v", mon.cbs)
}
mon.mu.Unlock()
}