mirror of https://github.com/golang/go.git
65 lines
1.8 KiB
Go
65 lines
1.8 KiB
Go
// Copyright 2020 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package eventtest supports logging events to a test.
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// You can use NewContext to create a context that knows how to deliver
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// telemetry events back to the test.
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// You must use this context or a derived one anywhere you want telemetry to be
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// correctly routed back to the test it was constructed with.
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// Any events delivered to a background context will be dropped.
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//
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// Importing this package will cause it to register a new global telemetry
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// exporter that understands the special contexts returned by NewContext.
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// This means you should not import this package if you are not going to call
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// NewContext.
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package eventtest
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import (
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"bytes"
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"context"
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"sync"
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"testing"
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"golang.org/x/tools/internal/event"
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"golang.org/x/tools/internal/event/core"
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"golang.org/x/tools/internal/event/export"
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"golang.org/x/tools/internal/event/label"
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)
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func init() {
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e := &testExporter{buffer: &bytes.Buffer{}}
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e.logger = export.LogWriter(e.buffer, false)
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event.SetExporter(export.Spans(e.processEvent))
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}
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type testingKeyType int
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const testingKey = testingKeyType(0)
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// NewContext returns a context you should use for the active test.
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func NewContext(ctx context.Context, t testing.TB) context.Context {
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return context.WithValue(ctx, testingKey, t)
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}
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type testExporter struct {
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mu sync.Mutex
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buffer *bytes.Buffer
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logger event.Exporter
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}
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func (w *testExporter) processEvent(ctx context.Context, ev core.Event, tm label.Map) context.Context {
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w.mu.Lock()
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defer w.mu.Unlock()
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// build our log message in buffer
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result := w.logger(ctx, ev, tm)
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v := ctx.Value(testingKey)
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// get the testing.TB
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if w.buffer.Len() > 0 && v != nil {
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v.(testing.TB).Log(w.buffer)
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}
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w.buffer.Truncate(0)
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return result
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}
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