blob: 9e9da529bdf9ae9e6f796bfc559f2356a493a033 [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.
// Any events delivered to a background context will be dropped.
// Importing this package will cause it to register a new global telemetry
// exporter that understands the special contexts returned by NewContext.
// This means you should not import this package if you are not going to call
// NewContext.
package eventtest
import (
func init() {
e := &testExporter{buffer: &bytes.Buffer{}}
e.logger = export.LogWriter(e.buffer, false)
type testingKeyType int
const testingKey = testingKeyType(0)
// NewContext returns a context you should use for the active test.
func NewContext(ctx context.Context, t testing.TB) context.Context {
return context.WithValue(ctx, testingKey, t)
type testExporter struct {
mu sync.Mutex
buffer *bytes.Buffer
logger event.Exporter
func (w *testExporter) processEvent(ctx context.Context, ev core.Event, tm label.Map) context.Context {
// build our log message in buffer
result := w.logger(ctx, ev, tm)
v := ctx.Value(testingKey)
// get the testing.TB
if w.buffer.Len() > 0 && v != nil {
return result