go - 如何测试从自定义配置构建的 zap Logger 的日志记录？

Question

我有一个从自定义配置(即 config.Build())生成的 Zap 记录器。我想通过在测试方法中调用例如 logger.Info() 来测试记录器，并断言结果以查看它是否符合配置集。我怎样才能做到这一点？

代码示例:

func GetLogger() *zap.Logger{
 config := &zap.Config{
  Encoding: "json",
  Level: zap.NewAtomicLevelAt(zapcore.InfoLevel),
  OutputPaths: []string{"stdout"},
  ErrorOutputPaths: []string{"stdout"},
  EncoderConfig: zapcore.EncoderConfig{
   MessageKey: "@m",
   LevelKey:    "@l",
   EncodeLevel: zapcore.CapitalLevelEncoder,
   TimeKey:    "@t",
   EncodeTime: zapcore.EpochMillisTimeEncoder,
   CallerKey:     "@c",
   EncodeCaller:  zapcore.ShortCallerEncoder,
   StacktraceKey: "@x",
  },
 }
 return config.Build()
}

Answer 1

zap 有一个特殊的 zaptest/observer 模块，用于单元测试:

package test

import (
    "testing"

    "go.uber.org/zap"
    "go.uber.org/zap/zaptest/observer"
)

func setupLogsCapture() (*zap.Logger, *observer.ObservedLogs) {
    core, logs := observer.New(zap.InfoLevel)
    return zap.New(core), logs
}

func Test(t *testing.T) {
    logger, logs := setupLogsCapture()
    
    logger.Warn("This is the warning")
    
    if logs.Len() != 1 {
        t.Errorf("No logs")
    } else {
        entry := logs.All()[0]
        if entry.Level != zap.WarnLevel || entry.Message != "This is the warning" {
            t.Errorf("Invalid log entry %v", entry)
        }
    }
}