Golang测试用例失败时日志记录方法

testing.T

log

t.Log

t.Errorf

zap

logrus

go test -v

bytes.Buffer

t.Failed()

Buffer

t.Log

t.Helper()

t.Log

t.Errorf

requestID

userID

zap

logrus

zap

package mypackage

import (
    "bytes"
    "log"
    "testing"

    "go.uber.org/zap"
    "go.uber.org/zap/zapcore"
)

// setupTestLogger sets up a zap logger that writes to a buffer.
// It returns the logger and the buffer.
func setupTestLogger() (*zap.Logger, *bytes.Buffer) {
    var buf bytes.Buffer
    encoderCfg := zap.NewProductionEncoderConfig()
    encoderCfg.EncodeTime = zapcore.ISO8601TimeEncoder // ISO8601 for better readability/parsing
    core := zapcore.NewCore(
        zapcore.NewJSONEncoder(encoderCfg),
        zapcore.AddSync(&buf),
        zapcore.DebugLevel, // Capture all levels for potential failure analysis
    )
    logger := zap.New(core)
    return logger, &buf
}

func TestSomethingFails(t *testing.T) {
    logger, logBuffer := setupTestLogger()
    defer func() {
        // Only dump logs if the test failed
        if t.Failed() {
            t.Logf("--- Captured Test Log Output ---\n%s", logBuffer.String())
        }
    }()

    logger.Info("Attempting to perform a critical operation", zap.String("operation_id", "abc-123"))
    // Simulate some complex logic that leads to a failure
    result := 1 + 1
    expected := 3
    if result != expected {
        logger.Error("Critical operation failed due to incorrect calculation",
            zap.Int("expected", expected),
            zap.Int("got", result),
            zap.String("context", "math_test"),
            zap.Stack("stack_trace"), // Capture stack trace on error
        )
        t.Errorf("Expected %d, got %d", expected, result)
    }
    logger.Debug("This debug message will only appear if the test fails and the buffer is dumped.")
}

func TestSomethingPasses(t *testing.T) {
    logger, logBuffer := setupTestLogger()
    defer func() {
        // For a passing test, this defer block won't print anything
        if t.Failed() {
            t.Logf("--- Captured Test Log Output ---\n%s", logBuffer.String())
        }
    }()
    logger.Info("This test is expected to pass, so its logs won't be visible unless it fails.")
    // Assertions for a passing test
    if 2+2 != 4 {
        t.Errorf("This should not happen, indicating a test logic error.")
    }
}

// 如果更倾向于使用标准库log，也可以这样集成
func TestStandardLogIntegration(t *testing.T) {
    var buf bytes.Buffer
    // 创建一个指向缓冲区的标准logger
    stdLogger := log.New(&buf, "TEST_STD: ", log.LstdFlags|log.Lshortfile)

    defer func() {
        if t.Failed() {
            t.Logf("--- Captured Standard Log Output ---\n%s", buf.String())
        }
    }()

    stdLogger.Println("This is a standard log message during test.")
    if "hello" != "world" {
        stdLogger.Printf("Error: Mismatch found! Expected '%s', got '%s'", "hello", "world")
        t.Errorf("String comparison failed")
    }
}