tendermint/libs/log/testing.go

package log

import (
	"testing"

	"github.com/rs/zerolog"
)

// TestingLogger was a legacy constructor that wrote logging output to
// standardoutput when in verbose mode, and no-op'ed test logs
// otherwise. Now it always no-ops, but if you need to see logs from
// tests, you can replace this call with `NewTestingLogger`
// constructor.
func TestingLogger() Logger {
	return NewNopLogger()
}

type testingWriter struct {
	t testing.TB
}

func (tw testingWriter) Write(in []byte) (int, error) {
	tw.t.Log(string(in))
	return len(in), nil
}

// NewTestingLogger converts a testing.T into a logging interface to
// make test failures and verbose provide better feedback associated
// with test failures. This logging instance is safe for use from
// multiple threads, but in general you should create one of these
// loggers ONCE for each *testing.T instance that you interact with.
//
// By default it collects only ERROR messages, or DEBUG messages in
// verbose mode, and relies on the underlying behavior of
// testing.T.Log()
//
// Users should be careful to ensure that no calls to this logger are
// made in goroutines that are running after (which, by the rules of
// testing.TB will panic.)
func NewTestingLogger(t testing.TB) Logger {
	level := LogLevelError
	if testing.Verbose() {
		level = LogLevelDebug
	}

	return NewTestingLoggerWithLevel(t, level)
}

// NewTestingLoggerWithLevel creates a testing logger instance at a
// specific level that wraps the behavior of testing.T.Log().
func NewTestingLoggerWithLevel(t testing.TB, level string) Logger {
	logLevel, err := zerolog.ParseLevel(level)
	if err != nil {
		t.Fatalf("failed to parse log level (%s): %v", level, err)
	}

	return defaultLogger{
		Logger: zerolog.New(newSyncWriter(testingWriter{t})).Level(logLevel),
	}
}