Testing Transport

The transports/testing package is the transport you want in test code: it captures every log entry into a mutex-safe in-memory library, exposing Messages, Data, and Metadata as typed fields on each captured LogLine.

For a usage walkthrough see the Mocking page in the logging API section. This page covers the package surface.

go get go.loglayer.dev/transports/testing

import lltest "go.loglayer.dev/transports/testing"

(The package name is testing, which collides with the standard testing package, most users alias the import as lltest.)

Setup

lib := &lltest.TestLoggingLibrary{}
trans := lltest.New(lltest.Config{
    BaseConfig: transport.BaseConfig{ID: "test"},
    Library:    lib,
})

log := loglayer.New(loglayer.Config{Transport: trans})

If Library is nil, the transport allocates one and exposes it as trans.Library.

Config

type Config struct {
    transport.BaseConfig
    Library *TestLoggingLibrary // nil → auto-allocate
}

LogLine Shape

type LogLine struct {
    Level    loglayer.LogLevel
    Messages []any
    Data     loglayer.Data // assembled fields + error map; nil when neither were set
    Metadata any           // raw value passed to WithMetadata
}

TestLoggingLibrary API

Method	Purpose
`Lines()`	Snapshot copy of all captured lines
`GetLastLine()`	Most recent line (does not remove); nil if empty
`PopLine()`	Most recent line (removes it); nil if empty
`ClearLines()`	Drop all captured lines
`Len()`	Number of captured lines
`Log(line)`	Manually append a line (useful for adapter tests)

All methods are safe for concurrent use.

Reaching the Library Back

The transport's GetLoggerInstance returns *TestLoggingLibrary:

lib := log.GetLoggerInstance("test").(*lltest.TestLoggingLibrary)
lib.ClearLines()

Fatal Behavior

This transport writes fatal entries normally; whether the process actually exits is the core's decision via Config.DisableFatalExit (default: exit). See Fatal Exits the Process.

Testing Transport ​

Setup ​

Config ​

LogLine Shape ​

TestLoggingLibrary API ​

Reaching the Library Back ​

Fatal Behavior ​

See Also ​