test: 补充真实功能验证测试

- ErrorMetrics 并发安全测试
- AsyncLogWriter 错误指标真实记录测试
- HTTP Server 超时配置真实验证
- Prometheus 指标 HTTP 端点真实测试
- 日志文件输出真实写入测试

internal/log/log_integration_test.go

@@ -0,0 +1,136 @@
+package log
+
+import (
+	"log/slog"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestInitWithConfig_FileOutput_Real(t *testing.T) {
+	logDir := t.TempDir()
+	logFile := filepath.Join(logDir, "test.log")
+
+	cfg := Config{
+		Level:   "info",
+		Output:  logFile,
+		MaxSize: 1, // 1MB
+	}
+
+	// 初始化日志
+	InitWithConfig(cfg)
+
+	// 写入日志
+	Info("test message", "key", "value")
+	Error("error message", "err", "test error")
+
+	// 验证文件被创建
+	if _, err := os.Stat(logFile); os.IsNotExist(err) {
+		t.Fatal("Log file was not created")
+	}
+
+	// 读取文件内容
+	content, err := os.ReadFile(logFile)
+	if err != nil {
+		t.Fatalf("Failed to read log file: %v", err)
+	}
+
+	// 验证内容
+	contentStr := string(content)
+	if !strings.Contains(contentStr, "test message") {
+		t.Error("Log file missing 'test message'")
+	}
+	if !strings.Contains(contentStr, "key") {
+		t.Error("Log file missing 'key' field")
+	}
+}
+
+func TestSanitizeAttrs_Real(t *testing.T) {
+	tests := []struct {
+		name     string
+		key      string
+		value    string
+		expected string
+	}{
+		{
+			name:     "token should be redacted",
+			key:      "api_token",
+			value:    "secret123",
+			expected: "[REDACTED]",
+		},
+		{
+			name:     "password should be redacted",
+			key:      "user_password",
+			value:    "mypassword",
+			expected: "[REDACTED]",
+		},
+		{
+			name:     "normal key should not be redacted",
+			key:      "user_name",
+			value:    "john",
+			expected: "john",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			attr := slog.String(tt.key, tt.value)
+			sanitized := sanitizeAttrs(nil, attr)
+
+			if sanitized.Value.String() != tt.expected {
+				t.Errorf("sanitizeAttrs() = %q, want %q", sanitized.Value.String(), tt.expected)
+			}
+		})
+	}
+}
+
+func TestIsSensitive_Real(t *testing.T) {
+	sensitiveKeys := []string{
+		"token",
+		"password",
+		"secret",
+		"api_key",
+		"private_key",
+	}
+
+	nonSensitiveKeys := []string{
+		"name",
+		"id",
+		"timestamp",
+		"message",
+	}
+
+	for _, key := range sensitiveKeys {
+		if !IsSensitive(key) {
+			t.Errorf("IsSensitive(%q) = false, want true", key)
+		}
+	}
+
+	for _, key := range nonSensitiveKeys {
+		if IsSensitive(key) {
+			t.Errorf("IsSensitive(%q) = true, want false", key)
+		}
+	}
+}
+
+func TestParseLevel_Real(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected slog.Level
+	}{
+		{"debug", slog.LevelDebug},
+		{"info", slog.LevelInfo},
+		{"warn", slog.LevelWarn},
+		{"error", slog.LevelError},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			level := parseLevel(tt.input)
+			if level != tt.expected {
+				t.Errorf("parseLevel(%q) = %d, want %d", tt.input, level, tt.expected)
+			}
+		})
+	}
+}