blob: 8c1cdce6d11c96d495f5e27502ccc99015ec4349 [file] [log] [blame]
// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package eventtest supports logging events to a test.
// You can use NewContext to create a context that knows how to deliver
// telemetry events back to the test.
// You must use this context or a derived one anywhere you want telemetry to be
// correctly routed back to the test it was constructed with.
package eventtest
import (
// NewContext returns a context you should use for the active test.
func NewContext(ctx context.Context, tb testing.TB) context.Context {
h := &testHandler{tb: tb}
return event.WithExporter(ctx, event.NewExporter(h, nil))
type testHandler struct {
tb testing.TB
printer logfmt.Printer
func (h *testHandler) Log(ctx context.Context, ev *event.Event) {
h.event(ctx, ev)
func (h *testHandler) Metric(ctx context.Context, ev *event.Event) {
h.event(ctx, ev)
func (h *testHandler) Annotate(ctx context.Context, ev *event.Event) {
h.event(ctx, ev)
func (h *testHandler) Start(ctx context.Context, ev *event.Event) context.Context {
h.event(ctx, ev)
return ctx
func (h *testHandler) End(ctx context.Context, ev *event.Event) {
h.event(ctx, ev)
func (h *testHandler) event(ctx context.Context, ev *event.Event) {
//TODO: choose between stdout and stderr based on the event
//TODO: decide if we should be calling h.tb.Fail()
h.printer.Event(os.Stdout, ev)
var InitialTime = func() time.Time {
t, _ := time.Parse(logfmt.TimeFormat, "2020/03/05 14:27:48")
return t
func ExporterOptions() *event.ExporterOptions {
nextTime := InitialTime
return &event.ExporterOptions{
Now: func() time.Time {
thisTime := nextTime
nextTime = nextTime.Add(time.Second)
return thisTime