blob: e9bd4beacb94694915e37b20549e9a5bbbf1a6a5 [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}
h.p = logfmt.NewPrinter(&h.buf)
return event.WithExporter(ctx, event.NewExporter(h))
type testHandler struct {
tb testing.TB
buf strings.Builder
p *logfmt.Printer
func (h *testHandler) Log(ctx context.Context, ev *event.Event) {
h.p.Log(ctx, ev)
func (h *testHandler) Metric(ctx context.Context, ev *event.Event) {
h.p.Metric(ctx, ev)
func (h *testHandler) Annotate(ctx context.Context, ev *event.Event) {
h.p.Annotate(ctx, ev)
func (h *testHandler) Start(ctx context.Context, ev *event.Event) context.Context {
ctx = h.p.Start(ctx, ev)
return ctx
func (h *testHandler) End(ctx context.Context, ev *event.Event) {
h.p.End(ctx, ev)
func (h *testHandler) deliver() {
if h.buf.Len() == 0 {
func TestNow() func() time.Time {
nextTime, _ := time.Parse(time.RFC3339Nano, "2020-03-05T14:27:48Z")
return func() time.Time {
thisTime := nextTime
nextTime = nextTime.Add(time.Second)
return thisTime