test(log): add comprehensive Logger type method tests

Tests all Logger methods: Trace/f/ln, Debug/f/ln, Info/f/ln,
Notice/f/ln, Warn/f/ln, Error/f/ln, Panic/f/ln, Print/f/ln,
Default(), SetInfoDepth, and panic-with-error behavior.

Previously these methods had near-zero direct test coverage.

.github/workflows/ci.yaml

@@ -1,23 +1,20 @@
 name: Go package
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Set up Go
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v5
         with:
-          go-version: "1.21"
-
-      - name: Install dependencies
-        run: go get .
+          go-version: "1.26"
 
       - name: Build
         run: go build -v ./...
 
       - name: Test
-        run: go test -v ./...
+        run: go test -race -v ./...

CRUSH.md

@@ -239,7 +239,7 @@ Still embeds viewer.html, but HTML now includes:
 
 ## Go Version & Dependencies
 
-- **Go version**: 1.24.4 (specified in go.mod)
+- **Go version**: 1.26.1 (specified in go.mod)
 - **Only external dependency**: `github.com/gorilla/websocket v1.5.3`
 
 ## Naming Conventions & Style
@@ -314,27 +314,17 @@ UI provides "Reconnect" button for this purpose.
 ### 6. Stderr Client Uses All Namespaces
 The built-in stderr client (created in `init()`) listens to all namespaces:
 ```go
-stderrClient = CreateClient(DefaultNamespace)
+stderrClient = CreateClient() // No args = all namespaces
 ```
 
-But only prints logs matching its own namespace in `logStdErr()`:
+It prints logs matching its level and namespace filter in `logStdErr()`:
 ```go
 if e.level >= c.LogLevel && c.matchesNamespace(e.Namespace) {
     fmt.Fprintf(os.Stderr, "%s\t%s\t[%s]\t%s\t%s\n", ...)
 }
 ```
 
-**Wait, that's a bug!** The stderr client is created with `DefaultNamespace` but should be created with no namespaces to see all logs. Let me check this.
-
-Actually looking at the code:
-```go
-stderrClient = CreateClient(DefaultNamespace)
-```
-
-This means stderr client only sees "default" namespace logs. This might be intentional, but seems like a bug. Should probably be:
-```go
-stderrClient = CreateClient() // No args = all namespaces
-```
+Since `CreateClient()` is called with no arguments, the Namespaces slice is empty, which means it matches all namespaces.
 
 ### 7. Grid Layout Updated
 The log viewer grid changed from 4 to 5 columns:
@@ -374,8 +364,9 @@ All existing tests pass with namespace support added.
 ## CI/CD
 
 GitHub Actions workflow (`.github/workflows/ci.yaml`):
-- Still uses Go 1.21 (should update to 1.24.4 to match go.mod)
-- No changes needed for v2 functionality
+- Uses Go 1.26, actions/checkout@v4, actions/setup-go@v5
+- Runs tests with `-race` flag
+- Triggers on push and pull_request
 
 ## Common Tasks
 

README.md

@@ -15,6 +15,7 @@ A real-time log viewer with WebSocket support and namespace filtering, written i
 - **Namespace filtering**: Subscribe to specific namespaces via WebSocket
 - **Frontend namespace selector**: Filter logs by namespace in the web UI
 - **Namespace API**: GET `/api/namespaces` to list all active namespaces
+- **Colored terminal output**: Log levels are color-coded in terminal (no external packages)
 
 ## Features
 
@@ -188,6 +189,40 @@ ws://localhost:8080/ws?namespaces=api,database  # Multiple namespaces
 - **Color Coding**: Different log levels are color-coded
 - **Reconnect**: Reconnect WebSocket with new namespace filter
 
+## Terminal Colors
+
+Log output to stderr is automatically colorized when writing to a terminal. Colors are disabled when output is piped or redirected to a file.
+
+### Color Scheme
+
+| Level  | Color        |
+|--------|--------------|
+| TRACE  | Gray         |
+| DEBUG  | Cyan         |
+| INFO   | Green        |
+| NOTICE | Blue         |
+| WARN   | Yellow       |
+| ERROR  | Red          |
+| PANIC  | Bold Red     |
+| FATAL  | Bold Red     |
+
+### Controlling Colors
+
+```go
+// Disable colors (e.g., for CI/CD or file output)
+logger.SetColorEnabled(false)
+
+// Enable colors explicitly
+logger.SetColorEnabled(true)
+
+// Check current state
+if logger.ColorEnabled() {
+    // colors are on
+}
+```
+
+Colors are implemented using standard ANSI escape codes with no external dependencies.
+
 ## Migration from v1
 
 ### Import Path

examples/basic/main.go

@@ -0,0 +1,36 @@
+// Example: basic usage of log-socket as a drop-in logger.
+//
+// This demonstrates using the package-level logging functions,
+// which work similarly to the standard library's log package.
+package main
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/taigrr/log-socket/v2/browser"
+	logger "github.com/taigrr/log-socket/v2/log"
+	"github.com/taigrr/log-socket/v2/ws"
+)
+
+func main() {
+	defer logger.Flush()
+
+	// Set the minimum log level (default is LTrace, showing everything)
+	logger.SetLogLevel(logger.LDebug)
+
+	// Package-level functions log to the "default" namespace
+	logger.Info("Application starting up")
+	logger.Debug("Debug mode enabled")
+	logger.Warnf("Config file not found at %s, using defaults", "/etc/app/config.yaml")
+	logger.Errorf("Failed to connect to database: %s", "connection refused")
+
+	// Print/Printf/Println are aliases for Info
+	logger.Println("This is equivalent to Infoln")
+
+	// Start the web UI so you can view logs at http://localhost:8080
+	http.HandleFunc("/ws", ws.LogSocketHandler)
+	http.HandleFunc("/", browser.LogSocketViewHandler)
+	fmt.Println("Log viewer available at http://localhost:8080")
+	logger.Fatal(http.ListenAndServe("0.0.0.0:8080", nil))
+}

examples/client/main.go

@@ -0,0 +1,63 @@
+// Example: programmatic log client with namespace filtering.
+//
+// This shows how to create a Client that receives log entries
+// programmatically, optionally filtered to specific namespaces.
+// Useful for building custom log processors, alerting, or forwarding.
+package main
+
+import (
+	"fmt"
+	"time"
+
+	logger "github.com/taigrr/log-socket/v2/log"
+)
+
+func main() {
+	defer logger.Flush()
+
+	// Create a client that receives ALL log entries
+	allLogs := logger.CreateClient()
+	allLogs.SetLogLevel(logger.LInfo)
+
+	// Create a client that only receives "database" and "auth" logs
+	securityLogs := logger.CreateClient("database", "auth")
+	securityLogs.SetLogLevel(logger.LWarn) // Only warnings and above
+
+	dbLog := logger.NewLogger("database")
+	authLog := logger.NewLogger("auth")
+	apiLog := logger.NewLogger("api")
+
+	// Process all logs
+	go func() {
+		for {
+			entry := allLogs.Get()
+			fmt.Printf("[ALL] %s [%s] %s: %s\n",
+				entry.Timestamp.Format(time.TimeOnly),
+				entry.Namespace, entry.Level, entry.Output)
+		}
+	}()
+
+	// Process only security-relevant warnings/errors
+	go func() {
+		for {
+			entry := securityLogs.Get()
+			if entry.Level == "ERROR" || entry.Level == "WARN" {
+				fmt.Printf("🚨 SECURITY ALERT [%s] %s: %s\n",
+					entry.Namespace, entry.Level, entry.Output)
+			}
+		}
+	}()
+
+	// Generate some logs
+	for i := 0; i < 5; i++ {
+		apiLog.Info("API request processed")
+		dbLog.Info("Query executed successfully")
+		dbLog.Warn("Connection pool running low")
+		authLog.Error("Brute force attempt detected")
+		time.Sleep(1 * time.Second)
+	}
+
+	// Clean up clients when done
+	allLogs.Destroy()
+	securityLogs.Destroy()
+}

examples/log-levels/main.go

@@ -0,0 +1,48 @@
+// Example: log level filtering and all available levels.
+//
+// log-socket supports 8 log levels from TRACE (most verbose)
+// to FATAL (least verbose). Setting a log level filters out
+// everything below it.
+package main
+
+import (
+	"fmt"
+
+	logger "github.com/taigrr/log-socket/v2/log"
+)
+
+func main() {
+	defer logger.Flush()
+
+	fmt.Println("=== All log levels (TRACE and above) ===")
+	logger.SetLogLevel(logger.LTrace)
+
+	logger.Trace("Detailed execution trace — variable x = 42")
+	logger.Debug("Processing request for user_id=123")
+	logger.Info("Server started on :8080")
+	logger.Notice("Configuration reloaded")
+	logger.Warn("Disk usage at 85%")
+	logger.Error("Failed to send email: SMTP timeout")
+	// logger.Panic("...") — would panic
+	// logger.Fatal("...") — would os.Exit(1)
+
+	fmt.Println("\n=== Formatted variants ===")
+	logger.Infof("Request took %dms", 42)
+	logger.Warnf("Retrying in %d seconds (attempt %d/%d)", 5, 2, 3)
+	logger.Errorf("HTTP %d: %s", 503, "Service Unavailable")
+
+	fmt.Println("\n=== Only WARN and above ===")
+	logger.SetLogLevel(logger.LWarn)
+
+	logger.Debug("This will NOT appear")
+	logger.Info("This will NOT appear either")
+	logger.Warn("This WILL appear")
+	logger.Error("This WILL appear too")
+
+	fmt.Println("\n=== Per-logger levels via namespaced loggers ===")
+	logger.SetLogLevel(logger.LTrace) // Reset global
+
+	appLog := logger.NewLogger("app")
+	appLog.Info("Namespaced loggers inherit the global output but tag entries")
+	appLog.Warnf("Something needs attention in the %s subsystem", "app")
+}

examples/namespaces/main.go

@@ -0,0 +1,73 @@
+// Example: namespace-based logging for organizing logs by component.
+//
+// Namespaces let you tag log entries by subsystem (api, database, auth, etc.)
+// and filter them in the web UI or via programmatic clients.
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"net/http"
+	"time"
+
+	"github.com/taigrr/log-socket/v2/browser"
+	logger "github.com/taigrr/log-socket/v2/log"
+	"github.com/taigrr/log-socket/v2/ws"
+)
+
+func main() {
+	defer logger.Flush()
+
+	// Create loggers for different subsystems
+	apiLog := logger.NewLogger("api")
+	dbLog := logger.NewLogger("database")
+	authLog := logger.NewLogger("auth")
+	cacheLog := logger.NewLogger("cache")
+
+	// Simulate application activity
+	go func() {
+		for {
+			apiLog.Infof("GET /api/users — 200 OK (%dms)", rand.Intn(200))
+			apiLog.Debugf("Request headers: Accept=application/json")
+			time.Sleep(1 * time.Second)
+		}
+	}()
+
+	go func() {
+		for {
+			dbLog.Infof("SELECT * FROM users — %d rows", rand.Intn(100))
+			if rand.Float64() < 0.3 {
+				dbLog.Warn("Slow query detected (>500ms)")
+			}
+			time.Sleep(2 * time.Second)
+		}
+	}()
+
+	go func() {
+		for {
+			if rand.Float64() < 0.7 {
+				authLog.Info("User login successful")
+			} else {
+				authLog.Error("Failed login attempt from 192.168.1.42")
+			}
+			time.Sleep(3 * time.Second)
+		}
+	}()
+
+	go func() {
+		for {
+			cacheLog.Tracef("Cache hit ratio: %.1f%%", rand.Float64()*100)
+			if rand.Float64() < 0.1 {
+				cacheLog.Warn("Cache eviction triggered")
+			}
+			time.Sleep(5 * time.Second)
+		}
+	}()
+
+	// The /api/namespaces endpoint lists all active namespaces
+	http.HandleFunc("/ws", ws.LogSocketHandler)
+	http.HandleFunc("/api/namespaces", ws.NamespacesHandler)
+	http.HandleFunc("/", browser.LogSocketViewHandler)
+	fmt.Println("Log viewer with namespace filtering at http://localhost:8080")
+	logger.Fatal(http.ListenAndServe("0.0.0.0:8080", nil))
+}

go.mod

@@ -1,5 +1,5 @@
 module github.com/taigrr/log-socket/v2
 
-go 1.25.4
+go 1.26.1
 
 require github.com/gorilla/websocket v1.5.3

log/bench_test.go

@@ -0,0 +1,171 @@
+package log
+
+import (
+	"fmt"
+	"testing"
+)
+
+const benchNS = "bench-isolated-ns"
+
+// benchClient creates a client with a continuous drain goroutine.
+// Returns the client and a stop function to call after b.StopTimer().
+func benchClient(ns string) (*Client, func()) {
+	c := CreateClient(ns)
+	c.SetLogLevel(LTrace)
+	done := make(chan struct{})
+	go func() {
+		for {
+			select {
+			case <-done:
+				return
+			case <-c.writer:
+			}
+		}
+	}()
+	return c, func() {
+		close(done)
+		c.Destroy()
+	}
+}
+
+// BenchmarkCreateClient measures client creation overhead.
+func BenchmarkCreateClient(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		c := CreateClient("bench")
+		c.Destroy()
+	}
+}
+
+// BenchmarkTrace benchmarks Logger.Trace.
+func BenchmarkTrace(b *testing.B) {
+	l := NewLogger(benchNS)
+	_, stop := benchClient(benchNS)
+	defer stop()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		l.Trace("benchmark trace message")
+	}
+}
+
+// BenchmarkTracef benchmarks formatted Logger.Tracef.
+func BenchmarkTracef(b *testing.B) {
+	l := NewLogger(benchNS)
+	_, stop := benchClient(benchNS)
+	defer stop()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		l.Tracef("benchmark trace message %d", i)
+	}
+}
+
+// BenchmarkDebug benchmarks Logger.Debug.
+func BenchmarkDebug(b *testing.B) {
+	l := NewLogger(benchNS)
+	_, stop := benchClient(benchNS)
+	defer stop()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		l.Debug("benchmark debug message")
+	}
+}
+
+// BenchmarkInfo benchmarks Logger.Info.
+func BenchmarkInfo(b *testing.B) {
+	l := NewLogger(benchNS)
+	_, stop := benchClient(benchNS)
+	defer stop()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		l.Info("benchmark info message")
+	}
+}
+
+// BenchmarkInfof benchmarks Logger.Infof with formatting.
+func BenchmarkInfof(b *testing.B) {
+	l := NewLogger(benchNS)
+	_, stop := benchClient(benchNS)
+	defer stop()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		l.Infof("user %s performed action %d", "testuser", i)
+	}
+}
+
+// BenchmarkWarn benchmarks Logger.Warn.
+func BenchmarkWarn(b *testing.B) {
+	l := NewLogger(benchNS)
+	_, stop := benchClient(benchNS)
+	defer stop()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		l.Warn("benchmark warn message")
+	}
+}
+
+// BenchmarkError benchmarks Logger.Error.
+func BenchmarkError(b *testing.B) {
+	l := NewLogger(benchNS)
+	_, stop := benchClient(benchNS)
+	defer stop()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		l.Error("benchmark error message")
+	}
+}
+
+// BenchmarkMultipleClients measures fan-out to multiple consumers.
+func BenchmarkMultipleClients(b *testing.B) {
+	const numClients = 5
+	l := NewLogger(benchNS)
+	stops := make([]func(), numClients)
+	for i := range stops {
+		_, stops[i] = benchClient(benchNS)
+	}
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		l.Info("benchmark multi-client")
+	}
+	b.StopTimer()
+	for _, stop := range stops {
+		stop()
+	}
+}
+
+// BenchmarkParallelInfo benchmarks concurrent Info calls from multiple goroutines.
+func BenchmarkParallelInfo(b *testing.B) {
+	l := NewLogger(benchNS)
+	_, stop := benchClient(benchNS)
+	defer stop()
+	b.ResetTimer()
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			l.Info("parallel benchmark info")
+		}
+	})
+}
+
+// BenchmarkNamespaceFiltering benchmarks logging when the consumer
+// filters by a different namespace (messages are not delivered).
+func BenchmarkNamespaceFiltering(b *testing.B) {
+	l := NewLogger(benchNS)
+	_, stop := benchClient("completely-different-ns")
+	defer stop()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		l.Info("filtered out message")
+	}
+}
+
+// BenchmarkFileInfo measures the cost of runtime.Caller for file info.
+func BenchmarkFileInfo(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		fileInfo(1)
+	}
+}
+
+// BenchmarkEntryCreation measures raw fmt.Sprint overhead (baseline).
+func BenchmarkEntryCreation(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		_ = fmt.Sprint("benchmark message ", i)
+	}
+}

log/color.go

@@ -0,0 +1,99 @@
+package log
+
+import (
+	"os"
+	"sync"
+)
+
+// ANSI color codes for terminal output
+const (
+	colorReset  = "\033[0m"
+	colorRed    = "\033[31m"
+	colorGreen  = "\033[32m"
+	colorYellow = "\033[33m"
+	colorBlue   = "\033[34m"
+	colorPurple = "\033[35m"
+	colorCyan   = "\033[36m"
+	colorWhite  = "\033[37m"
+	colorGray   = "\033[90m"
+
+	// Bold variants
+	colorBoldRed    = "\033[1;31m"
+	colorBoldYellow = "\033[1;33m"
+	colorBoldWhite  = "\033[1;37m"
+)
+
+var (
+	colorEnabled     = true
+	colorEnabledOnce sync.Once
+	colorMux         sync.RWMutex
+)
+
+// SetColorEnabled enables or disables colored output for stderr logging.
+// By default, color is enabled when stderr is a terminal.
+func SetColorEnabled(enabled bool) {
+	colorMux.Lock()
+	colorEnabled = enabled
+	colorMux.Unlock()
+}
+
+// ColorEnabled returns whether colored output is currently enabled.
+func ColorEnabled() bool {
+	colorMux.RLock()
+	defer colorMux.RUnlock()
+	return colorEnabled
+}
+
+// isTerminal checks if the given file descriptor is a terminal.
+// This is a simple heuristic that works on Unix-like systems.
+func isTerminal(f *os.File) bool {
+	stat, err := f.Stat()
+	if err != nil {
+		return false
+	}
+	return (stat.Mode() & os.ModeCharDevice) != 0
+}
+
+// initColorEnabled sets the default color state based on whether stderr is a terminal.
+func initColorEnabled() {
+	colorEnabledOnce.Do(func() {
+		colorEnabled = isTerminal(os.Stderr)
+	})
+}
+
+// levelColor returns the ANSI color code for a given log level.
+func levelColor(level Level) string {
+	switch level {
+	case LTrace:
+		return colorGray
+	case LDebug:
+		return colorCyan
+	case LInfo:
+		return colorGreen
+	case LNotice:
+		return colorBlue
+	case LWarn:
+		return colorYellow
+	case LError:
+		return colorRed
+	case LPanic:
+		return colorBoldRed
+	case LFatal:
+		return colorBoldRed
+	default:
+		return colorReset
+	}
+}
+
+// colorize wraps text with ANSI color codes if color is enabled.
+func colorize(text string, color string) string {
+	if !ColorEnabled() {
+		return text
+	}
+	return color + text + colorReset
+}
+
+// colorizeLevelText returns the level string with appropriate color.
+func colorizeLevelText(level string, lvl Level) string {
+	return colorize(level, levelColor(lvl))
+}

log/log.go

@@ -22,7 +22,8 @@ var (
 
 func init() {
 	namespaces = make(map[string]bool)
-	stderrClient = CreateClient(DefaultNamespace)
+	initColorEnabled()
+	stderrClient = CreateClient()
 	stderrClient.SetLogLevel(LTrace)
 	stderrFinished = make(chan bool, 1)
 	go stderrClient.logStdErr()
@@ -31,7 +32,10 @@ func init() {
 func (c *Client) logStdErr() {
 	for e := range c.writer {
 		if e.level >= c.LogLevel && c.matchesNamespace(e.Namespace) {
-			fmt.Fprintf(os.Stderr, "%s\t%s\t[%s]\t%s\t%s\n", e.Timestamp.String(), e.Level, e.Namespace, e.Output, e.File)
+			levelStr := colorizeLevelText(e.Level, e.level)
+			nsStr := colorize("["+e.Namespace+"]", colorPurple)
+			fileStr := colorize(e.File, colorGray)
+			fmt.Fprintf(os.Stderr, "%s\t%s\t%s\t%s\t%s\n", e.Timestamp.String(), levelStr, nsStr, e.Output, fileStr)
 		}
 	}
 	stderrFinished <- true
@@ -70,19 +74,19 @@ func Flush() {
 }
 
 func (c *Client) Destroy() error {
-	var otherClients []*Client
 	if !c.initialized {
 		panic(errors.New("cannot delete uninitialized client, did you use CreateClient?"))
 	}
 	sliceTex.Lock()
-	c.writer = nil
 	c.initialized = false
+	var otherClients []*Client
 	for _, x := range clients {
-		if x.initialized {
+		if x != c && x.initialized {
 			otherClients = append(otherClients, x)
 		}
 	}
 	clients = otherClients
+	c.writer = nil
 	sliceTex.Unlock()
 	return nil
 }
@@ -99,10 +103,13 @@ func createLog(e Entry) {
 	namespacesMux.Lock()
 	namespaces[e.Namespace] = true
 	namespacesMux.Unlock()
-	
+
 	sliceTex.Lock()
 	for _, c := range clients {
 		func(c *Client, e Entry) {
+			if c.writer == nil || !c.initialized {
+				return
+			}
 			// Filter by namespace if client has filters specified
 			if !c.matchesNamespace(e.Namespace) {
 				return
@@ -126,7 +133,7 @@ func createLog(e Entry) {
 func GetNamespaces() []string {
 	namespacesMux.RLock()
 	defer namespacesMux.RUnlock()
-	
+
 	result := make([]string, 0, len(namespaces))
 	for ns := range namespaces {
 		result = append(result, ns)
@@ -417,7 +424,7 @@ func Panic(args ...any) {
 		Namespace: DefaultNamespace,
 	}
 	createLog(e)
-	if len(args) >= 0 {
+	if len(args) > 0 {
 		switch args[0].(type) {
 		case error:
 			panic(args[0])
@@ -441,7 +448,7 @@ func Panicf(format string, args ...any) {
 		Namespace: DefaultNamespace,
 	}
 	createLog(e)
-	if len(args) >= 0 {
+	if len(args) > 0 {
 		switch args[0].(type) {
 		case error:
 			panic(args[0])
@@ -464,7 +471,7 @@ func Panicln(args ...any) {
 		Namespace: DefaultNamespace,
 	}
 	createLog(e)
-	if len(args) >= 0 {
+	if len(args) > 0 {
 		switch args[0].(type) {
 		case error:
 			panic(args[0])
@@ -549,3 +556,37 @@ func fileInfo(skip int) string {
 	}
 	return fmt.Sprintf("%s:%d", file, line)
 }
+
+// Broadcast sends an [Entry] to all registered clients. This is the public
+// entry point used by adapter packages (such as the slog handler) that
+// construct entries themselves. The unexported level field is inferred from
+// [Entry.Level] when not already set.
+func Broadcast(e Entry) {
+	if e.level == 0 && e.Level != "" && e.Level != "TRACE" {
+		e.level = parseLevelString(e.Level)
+	}
+	createLog(e)
+}
+
+func parseLevelString(s string) Level {
+	switch s {
+	case "TRACE":
+		return LTrace
+	case "DEBUG":
+		return LDebug
+	case "INFO":
+		return LInfo
+	case "NOTICE":
+		return LNotice
+	case "WARN":
+		return LWarn
+	case "ERROR":
+		return LError
+	case "PANIC":
+		return LPanic
+	case "FATAL":
+		return LFatal
+	default:
+		return LInfo
+	}
+}

log/log_test.go

@@ -4,8 +4,21 @@ import (
 	"strconv"
 	"sync"
 	"testing"
+	"time"
 )
 
+// getEntry reads from a client with a timeout to avoid hanging tests.
+func getEntry(c *Client, timeout time.Duration) (Entry, bool) {
+	ch := make(chan Entry, 1)
+	go func() { ch <- c.Get() }()
+	select {
+	case e := <-ch:
+		return e, true
+	case <-time.After(timeout):
+		return Entry{}, false
+	}
+}
+
 // Test CreateClient() and Client.Destroy()
 func TestCreateDestroy(t *testing.T) {
 	// Ensure only stderr exists at the beginning
@@ -64,70 +77,477 @@ func TestOrder(t *testing.T) {
 			t.Error("Trace input doesn't match output")
 		}
 	}
+	c.Destroy()
 }
 
-// Debug prints out logs on debug level
 func TestDebug(t *testing.T) {
-	Debug("Test of Debug")
-	//	if logLevel >= LDebug {
-	//		entry := logger.WithFields(logrus.Fields{})
-	//		entry.Data["file"] = fileInfo(2)
-	//		entry.Debug(args...)
-	//	}
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LDebug)
+
+	Debug("debug message")
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out waiting for debug entry")
+	}
+	if e.Level != "DEBUG" {
+		t.Errorf("level = %q, want DEBUG", e.Level)
+	}
+	if e.Output != "debug message" {
+		t.Errorf("output = %q, want %q", e.Output, "debug message")
+	}
+	if e.Namespace != DefaultNamespace {
+		t.Errorf("namespace = %q, want %q", e.Namespace, DefaultNamespace)
+	}
+	c.Destroy()
+}
+
+func TestDebugf(t *testing.T) {
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LDebug)
+
+	Debugf("hello %s %d", "world", 42)
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "hello world 42" {
+		t.Errorf("output = %q, want %q", e.Output, "hello world 42")
+	}
+	c.Destroy()
 }
 
-// Info prints out logs on info level
 func TestInfo(t *testing.T) {
-	//	if logLevel >= LInfo {
-	//		entry := logger.WithFields(logrus.Fields{})
-	//		entry.Data["file"] = fileInfo(2)
-	//		entry.Info(args...)
-	//	}
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LInfo)
+
+	Info("info message")
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out waiting for info entry")
+	}
+	if e.Level != "INFO" {
+		t.Errorf("level = %q, want INFO", e.Level)
+	}
+	if e.Output != "info message" {
+		t.Errorf("output = %q, want %q", e.Output, "info message")
+	}
+	c.Destroy()
+}
+
+func TestInfof(t *testing.T) {
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LInfo)
+
+	Infof("count: %d", 99)
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "count: 99" {
+		t.Errorf("output = %q, want %q", e.Output, "count: 99")
+	}
+	c.Destroy()
 }
 
-// Print prints out logs on info level
 func TestPrint(t *testing.T) {
-	//	if logLevel >= LInfo {
-	//		entry := logger.WithFields(logrus.Fields{})
-	//		entry.Data["file"] = fileInfo(2)
-	//		entry.Info(args...)
-	//	}
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LInfo)
+
+	Print("print message")
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	// Print is an alias for Info
+	if e.Level != "INFO" {
+		t.Errorf("level = %q, want INFO", e.Level)
+	}
+	if e.Output != "print message" {
+		t.Errorf("output = %q, want %q", e.Output, "print message")
+	}
+	c.Destroy()
+}
+
+func TestPrintf(t *testing.T) {
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LInfo)
+
+	Printf("formatted %s", "print")
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "formatted print" {
+		t.Errorf("output = %q, want %q", e.Output, "formatted print")
+	}
+	c.Destroy()
+}
+
+func TestNotice(t *testing.T) {
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LNotice)
+
+	Notice("notice message")
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Level != "NOTICE" {
+		t.Errorf("level = %q, want NOTICE", e.Level)
+	}
+	c.Destroy()
 }
 
-// Warn prints out logs on warn level
 func TestWarn(t *testing.T) {
-	//	if logLevel >= LWarn {
-	//		entry := logger.WithFields(logrus.Fields{})
-	//		entry.Data["file"] = fileInfo(2)
-	//		entry.Warn(args...)
-	//	}
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LWarn)
+
+	Warn("warning message")
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out waiting for warn entry")
+	}
+	if e.Level != "WARN" {
+		t.Errorf("level = %q, want WARN", e.Level)
+	}
+	if e.Output != "warning message" {
+		t.Errorf("output = %q, want %q", e.Output, "warning message")
+	}
+	c.Destroy()
+}
+
+func TestWarnf(t *testing.T) {
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LWarn)
+
+	Warnf("warn %d", 1)
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "warn 1" {
+		t.Errorf("output = %q, want %q", e.Output, "warn 1")
+	}
+	c.Destroy()
 }
 
-// Error prints out logs on error level
 func TestError(t *testing.T) {
-	//	if logLevel >= LError {
-	//		entry := logger.WithFields(logrus.Fields{})
-	//		entry.Data["file"] = fileInfo(2)
-	//		entry.Error(args...)
-	//	}
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LError)
+
+	Error("error message")
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out waiting for error entry")
+	}
+	if e.Level != "ERROR" {
+		t.Errorf("level = %q, want ERROR", e.Level)
+	}
+	if e.Output != "error message" {
+		t.Errorf("output = %q, want %q", e.Output, "error message")
+	}
+	c.Destroy()
 }
 
-// Fatal prints out logs on fatal level
-func TestFatal(t *testing.T) {
-	//	if logLevel >= LFatal {
-	//		entry := logger.WithFields(logrus.Fields{})
-	//		entry.Data["file"] = fileInfo(2)
-	//		entry.Fatal(args...)
-	//	}
+func TestErrorf(t *testing.T) {
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LError)
+
+	Errorf("err: %s", "something broke")
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "err: something broke" {
+		t.Errorf("output = %q, want %q", e.Output, "err: something broke")
+	}
+	c.Destroy()
 }
 
-// Panic prints out logs on panic level
 func TestPanic(t *testing.T) {
-	//	if logLevel >= LPanic {
-	//		entry := logger.WithFields(logrus.Fields{})
-	//		entry.Data["file"] = fileInfo(2)
-	//		entry.Panic(args...)
-	//	}
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LPanic)
+
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.Error("expected panic, got nil")
+		}
+		c.Destroy()
+	}()
+
+	Panic("panic message")
+}
+
+func TestPanicf(t *testing.T) {
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LPanic)
+
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.Error("expected panic, got nil")
+		}
+		c.Destroy()
+	}()
+
+	Panicf("panic %d", 42)
+}
+
+func TestPanicln(t *testing.T) {
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LPanic)
+
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.Error("expected panic, got nil")
+		}
+		c.Destroy()
+	}()
+
+	Panicln("panic line")
+}
+
+// TestLogLevelFiltering verifies that the client's log level is stored correctly.
+// Note: level filtering only applies to stderr output, not to client channels.
+// All entries matching the namespace are delivered to the client channel regardless of level.
+func TestLogLevelFiltering(t *testing.T) {
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LWarn)
+
+	if c.GetLogLevel() != LWarn {
+		t.Errorf("expected log level LWarn, got %d", c.GetLogLevel())
+	}
+
+	// Both entries arrive at the client channel (level filtering is stderr-only)
+	Info("info message")
+	Warn("warn message")
+
+	e1, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out waiting for first entry")
+	}
+	if e1.Output != "info message" {
+		t.Errorf("expected 'info message', got %q", e1.Output)
+	}
+
+	e2, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out waiting for second entry")
+	}
+	if e2.Output != "warn message" {
+		t.Errorf("expected 'warn message', got %q", e2.Output)
+	}
+	c.Destroy()
+}
+
+// TestNamespaceFiltering verifies clients only receive matching namespaces.
+func TestNamespaceFiltering(t *testing.T) {
+	c := CreateClient("api")
+	c.SetLogLevel(LTrace)
+
+	apiLogger := NewLogger("api")
+	dbLogger := NewLogger("database")
+
+	// Log to database namespace — should not arrive at "api" client
+	dbLogger.Info("db message")
+
+	// Log to api namespace — should arrive
+	apiLogger.Info("api message")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out waiting for api entry")
+	}
+	if e.Output != "api message" {
+		t.Errorf("expected 'api message', got %q", e.Output)
+	}
+	if e.Namespace != "api" {
+		t.Errorf("namespace = %q, want 'api'", e.Namespace)
+	}
+	c.Destroy()
+}
+
+// TestMultiNamespaceClient verifies a client subscribed to multiple namespaces.
+func TestMultiNamespaceClient(t *testing.T) {
+	c := CreateClient("api", "auth")
+	c.SetLogLevel(LTrace)
+
+	apiLogger := NewLogger("api")
+	authLogger := NewLogger("auth")
+	dbLogger := NewLogger("database")
+
+	dbLogger.Info("db message")   // filtered out
+	apiLogger.Info("api message") // should arrive
+	authLogger.Info("auth message") // should arrive
+
+	e1, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out waiting for first entry")
+	}
+	if e1.Output != "api message" {
+		t.Errorf("first entry = %q, want 'api message'", e1.Output)
+	}
+
+	e2, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out waiting for second entry")
+	}
+	if e2.Output != "auth message" {
+		t.Errorf("second entry = %q, want 'auth message'", e2.Output)
+	}
+	c.Destroy()
+}
+
+// TestGetNamespaces verifies the namespace registry.
+func TestGetNamespaces(t *testing.T) {
+	l := NewLogger("test-ns-registry")
+	l.Info("register this namespace")
+
+	nss := GetNamespaces()
+	found := false
+	for _, ns := range nss {
+		if ns == "test-ns-registry" {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Errorf("expected 'test-ns-registry' in GetNamespaces(), got %v", nss)
+	}
+}
+
+// TestLoggerDebugln verifies the Debugln method on Logger.
+func TestLoggerDebugln(t *testing.T) {
+	c := CreateClient("debugln-test")
+	c.SetLogLevel(LDebug)
+
+	l := NewLogger("debugln-test")
+	l.Debugln("debugln message")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Level != "DEBUG" {
+		t.Errorf("level = %q, want DEBUG", e.Level)
+	}
+	// Sprintln appends a newline
+	if e.Output != "debugln message\n" {
+		t.Errorf("output = %q, want %q", e.Output, "debugln message\n")
+	}
+	c.Destroy()
+}
+
+// TestNewLoggerEmptyNamespace verifies empty namespace defaults to DefaultNamespace.
+func TestNewLoggerEmptyNamespace(t *testing.T) {
+	l := NewLogger("")
+	if l.Namespace != DefaultNamespace {
+		t.Errorf("namespace = %q, want %q", l.Namespace, DefaultNamespace)
+	}
+}
+
+// TestFileInfo verifies fileInfo returns a non-empty file:line string.
+func TestFileInfo(t *testing.T) {
+	fi := fileInfo(1)
+	if fi == "" || fi == "<???>:1" {
+		t.Errorf("fileInfo returned unexpected value: %q", fi)
+	}
+}
+
+// TestColorize verifies color wrapping.
+func TestColorize(t *testing.T) {
+	SetColorEnabled(true)
+	result := colorize("hello", colorRed)
+	expected := colorRed + "hello" + colorReset
+	if result != expected {
+		t.Errorf("colorize with color enabled: got %q, want %q", result, expected)
+	}
+
+	SetColorEnabled(false)
+	result = colorize("hello", colorRed)
+	if result != "hello" {
+		t.Errorf("colorize with color disabled: got %q, want %q", result, "hello")
+	}
+
+	// Restore default
+	SetColorEnabled(true)
+}
+
+// TestParseLevelString verifies level string parsing.
+func TestParseLevelString(t *testing.T) {
+	tests := []struct {
+		input string
+		want  Level
+	}{
+		{"TRACE", LTrace},
+		{"DEBUG", LDebug},
+		{"INFO", LInfo},
+		{"NOTICE", LNotice},
+		{"WARN", LWarn},
+		{"ERROR", LError},
+		{"PANIC", LPanic},
+		{"FATAL", LFatal},
+		{"UNKNOWN", LInfo}, // default
+		{"", LInfo},        // default
+	}
+	for _, tt := range tests {
+		got := parseLevelString(tt.input)
+		if got != tt.want {
+			t.Errorf("parseLevelString(%q) = %d, want %d", tt.input, got, tt.want)
+		}
+	}
+}
+
+// TestBroadcast verifies the public Broadcast function.
+func TestBroadcast(t *testing.T) {
+	c := CreateClient("broadcast-ns")
+	c.SetLogLevel(LTrace)
+
+	e := Entry{
+		Timestamp: time.Now(),
+		Output:    "broadcast test",
+		File:      "test.go:1",
+		Level:     "WARN",
+		Namespace: "broadcast-ns",
+	}
+	Broadcast(e)
+
+	got, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if got.Output != "broadcast test" {
+		t.Errorf("output = %q, want %q", got.Output, "broadcast test")
+	}
+	if got.Level != "WARN" {
+		t.Errorf("level = %q, want WARN", got.Level)
+	}
+	c.Destroy()
+}
+
+// TestMatchesNamespace verifies the namespace matching helper.
+func TestMatchesNamespace(t *testing.T) {
+	// Client with no namespace filter matches everything
+	c := CreateClient()
+	if !c.matchesNamespace("anything") {
+		t.Error("empty Namespaces should match all")
+	}
+	c.Destroy()
+
+	// Client with specific namespaces
+	c2 := CreateClient("api", "auth")
+	if !c2.matchesNamespace("api") {
+		t.Error("should match 'api'")
+	}
+	if !c2.matchesNamespace("auth") {
+		t.Error("should match 'auth'")
+	}
+	if c2.matchesNamespace("database") {
+		t.Error("should not match 'database'")
+	}
+	c2.Destroy()
 }
 
 func TestFlush(t *testing.T) {

log/logger.go

@@ -28,7 +28,7 @@ func (l Logger) Trace(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "TRACE",
 		level:     LTrace,
 		Namespace: l.Namespace,
@@ -42,7 +42,7 @@ func (l Logger) Tracef(format string, args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "TRACE",
 		level:     LTrace,
 		Namespace: l.Namespace,
@@ -56,7 +56,7 @@ func (l Logger) Traceln(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "TRACE",
 		level:     LTrace,
 		Namespace: l.Namespace,
@@ -70,7 +70,7 @@ func (l Logger) Debug(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "DEBUG",
 		level:     LDebug,
 		Namespace: l.Namespace,
@@ -84,7 +84,21 @@ func (l Logger) Debugf(format string, args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
+		Level:     "DEBUG",
+		level:     LDebug,
+		Namespace: l.Namespace,
+	}
+	createLog(e)
+}
+
+// Debugln prints out logs on debug level with a newline
+func (l Logger) Debugln(args ...any) {
+	output := fmt.Sprintln(args...)
+	e := Entry{
+		Timestamp: time.Now(),
+		Output:    output,
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "DEBUG",
 		level:     LDebug,
 		Namespace: l.Namespace,
@@ -98,7 +112,7 @@ func (l Logger) Info(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "INFO",
 		level:     LInfo,
 		Namespace: l.Namespace,
@@ -112,7 +126,7 @@ func (l Logger) Infof(format string, args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "INFO",
 		level:     LInfo,
 		Namespace: l.Namespace,
@@ -126,7 +140,7 @@ func (l Logger) Infoln(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "INFO",
 		level:     LInfo,
 		Namespace: l.Namespace,
@@ -140,7 +154,7 @@ func (l Logger) Notice(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "NOTICE",
 		level:     LNotice,
 		Namespace: l.Namespace,
@@ -154,7 +168,7 @@ func (l Logger) Noticef(format string, args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "NOTICE",
 		level:     LNotice,
 		Namespace: l.Namespace,
@@ -168,7 +182,7 @@ func (l Logger) Noticeln(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "NOTICE",
 		level:     LNotice,
 		Namespace: l.Namespace,
@@ -182,7 +196,7 @@ func (l Logger) Warn(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "WARN",
 		level:     LWarn,
 		Namespace: l.Namespace,
@@ -196,7 +210,7 @@ func (l Logger) Warnf(format string, args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "WARN",
 		level:     LWarn,
 		Namespace: l.Namespace,
@@ -210,7 +224,7 @@ func (l Logger) Warnln(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "WARN",
 		level:     LWarn,
 		Namespace: l.Namespace,
@@ -224,7 +238,7 @@ func (l Logger) Error(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "ERROR",
 		level:     LError,
 		Namespace: l.Namespace,
@@ -238,7 +252,7 @@ func (l Logger) Errorf(format string, args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "ERROR",
 		level:     LError,
 		Namespace: l.Namespace,
@@ -252,7 +266,7 @@ func (l Logger) Errorln(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "ERROR",
 		level:     LError,
 		Namespace: l.Namespace,
@@ -266,13 +280,13 @@ func (l Logger) Panic(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "PANIC",
 		level:     LPanic,
 		Namespace: l.Namespace,
 	}
 	createLog(e)
-	if len(args) >= 0 {
+	if len(args) > 0 {
 		switch args[0].(type) {
 		case error:
 			panic(args[0])
@@ -290,13 +304,13 @@ func (l Logger) Panicf(format string, args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "PANIC",
 		level:     LPanic,
 		Namespace: l.Namespace,
 	}
 	createLog(e)
-	if len(args) >= 0 {
+	if len(args) > 0 {
 		switch args[0].(type) {
 		case error:
 			panic(args[0])
@@ -314,13 +328,13 @@ func (l Logger) Panicln(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "PANIC",
 		level:     LPanic,
 		Namespace: l.Namespace,
 	}
 	createLog(e)
-	if len(args) >= 0 {
+	if len(args) > 0 {
 		switch args[0].(type) {
 		case error:
 			panic(args[0])
@@ -338,7 +352,7 @@ func (l Logger) Fatal(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "FATAL",
 		level:     LFatal,
 		Namespace: l.Namespace,
@@ -354,7 +368,7 @@ func (l Logger) Fatalf(format string, args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "FATAL",
 		level:     LFatal,
 		Namespace: l.Namespace,
@@ -370,7 +384,7 @@ func (l Logger) Fatalln(args ...any) {
 	e := Entry{
 		Timestamp: time.Now(),
 		Output:    output,
-		File:      fileInfo(l.FileInfoDepth),
+		File:      fileInfo(2 + l.FileInfoDepth),
 		Level:     "FATAL",
 		level:     LFatal,
 		Namespace: l.Namespace,

log/logger_test.go

@@ -0,0 +1,518 @@
+package log
+
+import (
+	"testing"
+	"time"
+)
+
+func TestLoggerTrace(t *testing.T) {
+	c := CreateClient("logger-trace")
+	c.SetLogLevel(LTrace)
+
+	l := NewLogger("logger-trace")
+	l.Trace("trace message")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Level != "TRACE" {
+		t.Errorf("level = %q, want TRACE", e.Level)
+	}
+	if e.Output != "trace message" {
+		t.Errorf("output = %q, want %q", e.Output, "trace message")
+	}
+	if e.Namespace != "logger-trace" {
+		t.Errorf("namespace = %q, want %q", e.Namespace, "logger-trace")
+	}
+	c.Destroy()
+}
+
+func TestLoggerTracef(t *testing.T) {
+	c := CreateClient("logger-tracef")
+	c.SetLogLevel(LTrace)
+
+	l := NewLogger("logger-tracef")
+	l.Tracef("trace %s %d", "msg", 1)
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Level != "TRACE" {
+		t.Errorf("level = %q, want TRACE", e.Level)
+	}
+	if e.Output != "trace msg 1" {
+		t.Errorf("output = %q, want %q", e.Output, "trace msg 1")
+	}
+	c.Destroy()
+}
+
+func TestLoggerTraceln(t *testing.T) {
+	c := CreateClient("logger-traceln")
+	c.SetLogLevel(LTrace)
+
+	l := NewLogger("logger-traceln")
+	l.Traceln("trace line")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Level != "TRACE" {
+		t.Errorf("level = %q, want TRACE", e.Level)
+	}
+	if e.Output != "trace line\n" {
+		t.Errorf("output = %q, want %q", e.Output, "trace line\n")
+	}
+	c.Destroy()
+}
+
+func TestLoggerDebug(t *testing.T) {
+	c := CreateClient("logger-debug")
+	c.SetLogLevel(LDebug)
+
+	l := NewLogger("logger-debug")
+	l.Debug("debug message")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Level != "DEBUG" {
+		t.Errorf("level = %q, want DEBUG", e.Level)
+	}
+	if e.Output != "debug message" {
+		t.Errorf("output = %q, want %q", e.Output, "debug message")
+	}
+	c.Destroy()
+}
+
+func TestLoggerDebugf(t *testing.T) {
+	c := CreateClient("logger-debugf")
+	c.SetLogLevel(LDebug)
+
+	l := NewLogger("logger-debugf")
+	l.Debugf("debug %d", 42)
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "debug 42" {
+		t.Errorf("output = %q, want %q", e.Output, "debug 42")
+	}
+	c.Destroy()
+}
+
+func TestLoggerInfo(t *testing.T) {
+	c := CreateClient("logger-info")
+	c.SetLogLevel(LInfo)
+
+	l := NewLogger("logger-info")
+	l.Info("info message")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Level != "INFO" {
+		t.Errorf("level = %q, want INFO", e.Level)
+	}
+	if e.Output != "info message" {
+		t.Errorf("output = %q, want %q", e.Output, "info message")
+	}
+	c.Destroy()
+}
+
+func TestLoggerInfof(t *testing.T) {
+	c := CreateClient("logger-infof")
+	c.SetLogLevel(LInfo)
+
+	l := NewLogger("logger-infof")
+	l.Infof("count: %d", 99)
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "count: 99" {
+		t.Errorf("output = %q, want %q", e.Output, "count: 99")
+	}
+	c.Destroy()
+}
+
+func TestLoggerInfoln(t *testing.T) {
+	c := CreateClient("logger-infoln")
+	c.SetLogLevel(LInfo)
+
+	l := NewLogger("logger-infoln")
+	l.Infoln("info line")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "info line\n" {
+		t.Errorf("output = %q, want %q", e.Output, "info line\n")
+	}
+	c.Destroy()
+}
+
+func TestLoggerNotice(t *testing.T) {
+	c := CreateClient("logger-notice")
+	c.SetLogLevel(LNotice)
+
+	l := NewLogger("logger-notice")
+	l.Notice("notice message")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Level != "NOTICE" {
+		t.Errorf("level = %q, want NOTICE", e.Level)
+	}
+	if e.Output != "notice message" {
+		t.Errorf("output = %q, want %q", e.Output, "notice message")
+	}
+	c.Destroy()
+}
+
+func TestLoggerNoticef(t *testing.T) {
+	c := CreateClient("logger-noticef")
+	c.SetLogLevel(LNotice)
+
+	l := NewLogger("logger-noticef")
+	l.Noticef("notice %s", "formatted")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "notice formatted" {
+		t.Errorf("output = %q, want %q", e.Output, "notice formatted")
+	}
+	c.Destroy()
+}
+
+func TestLoggerNoticeln(t *testing.T) {
+	c := CreateClient("logger-noticeln")
+	c.SetLogLevel(LNotice)
+
+	l := NewLogger("logger-noticeln")
+	l.Noticeln("notice line")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "notice line\n" {
+		t.Errorf("output = %q, want %q", e.Output, "notice line\n")
+	}
+	c.Destroy()
+}
+
+func TestLoggerWarn(t *testing.T) {
+	c := CreateClient("logger-warn")
+	c.SetLogLevel(LWarn)
+
+	l := NewLogger("logger-warn")
+	l.Warn("warn message")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Level != "WARN" {
+		t.Errorf("level = %q, want WARN", e.Level)
+	}
+	if e.Output != "warn message" {
+		t.Errorf("output = %q, want %q", e.Output, "warn message")
+	}
+	c.Destroy()
+}
+
+func TestLoggerWarnf(t *testing.T) {
+	c := CreateClient("logger-warnf")
+	c.SetLogLevel(LWarn)
+
+	l := NewLogger("logger-warnf")
+	l.Warnf("warn %d", 1)
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "warn 1" {
+		t.Errorf("output = %q, want %q", e.Output, "warn 1")
+	}
+	c.Destroy()
+}
+
+func TestLoggerWarnln(t *testing.T) {
+	c := CreateClient("logger-warnln")
+	c.SetLogLevel(LWarn)
+
+	l := NewLogger("logger-warnln")
+	l.Warnln("warn line")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "warn line\n" {
+		t.Errorf("output = %q, want %q", e.Output, "warn line\n")
+	}
+	c.Destroy()
+}
+
+func TestLoggerError(t *testing.T) {
+	c := CreateClient("logger-error")
+	c.SetLogLevel(LError)
+
+	l := NewLogger("logger-error")
+	l.Error("error message")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Level != "ERROR" {
+		t.Errorf("level = %q, want ERROR", e.Level)
+	}
+	if e.Output != "error message" {
+		t.Errorf("output = %q, want %q", e.Output, "error message")
+	}
+	c.Destroy()
+}
+
+func TestLoggerErrorf(t *testing.T) {
+	c := CreateClient("logger-errorf")
+	c.SetLogLevel(LError)
+
+	l := NewLogger("logger-errorf")
+	l.Errorf("err: %s", "something broke")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "err: something broke" {
+		t.Errorf("output = %q, want %q", e.Output, "err: something broke")
+	}
+	c.Destroy()
+}
+
+func TestLoggerErrorln(t *testing.T) {
+	c := CreateClient("logger-errorln")
+	c.SetLogLevel(LError)
+
+	l := NewLogger("logger-errorln")
+	l.Errorln("error line")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "error line\n" {
+		t.Errorf("output = %q, want %q", e.Output, "error line\n")
+	}
+	c.Destroy()
+}
+
+func TestLoggerPanic(t *testing.T) {
+	c := CreateClient("logger-panic")
+	c.SetLogLevel(LPanic)
+
+	l := NewLogger("logger-panic")
+
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.Error("expected panic, got nil")
+		}
+		// Verify the entry was broadcast
+		e, ok := getEntry(c, time.Second)
+		if !ok {
+			t.Fatal("timed out waiting for panic entry")
+		}
+		if e.Level != "PANIC" {
+			t.Errorf("level = %q, want PANIC", e.Level)
+		}
+		if e.Namespace != "logger-panic" {
+			t.Errorf("namespace = %q, want %q", e.Namespace, "logger-panic")
+		}
+		c.Destroy()
+	}()
+
+	l.Panic("panic message")
+}
+
+func TestLoggerPanicf(t *testing.T) {
+	c := CreateClient("logger-panicf")
+	c.SetLogLevel(LPanic)
+
+	l := NewLogger("logger-panicf")
+
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.Error("expected panic, got nil")
+		}
+		e, ok := getEntry(c, time.Second)
+		if !ok {
+			t.Fatal("timed out")
+		}
+		if e.Output != "panic 42" {
+			t.Errorf("output = %q, want %q", e.Output, "panic 42")
+		}
+		c.Destroy()
+	}()
+
+	l.Panicf("panic %d", 42)
+}
+
+func TestLoggerPanicln(t *testing.T) {
+	c := CreateClient("logger-panicln")
+	c.SetLogLevel(LPanic)
+
+	l := NewLogger("logger-panicln")
+
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.Error("expected panic, got nil")
+		}
+		e, ok := getEntry(c, time.Second)
+		if !ok {
+			t.Fatal("timed out")
+		}
+		if e.Output != "panic line\n" {
+			t.Errorf("output = %q, want %q", e.Output, "panic line\n")
+		}
+		c.Destroy()
+	}()
+
+	l.Panicln("panic line")
+}
+
+func TestLoggerPrint(t *testing.T) {
+	c := CreateClient("logger-print")
+	c.SetLogLevel(LInfo)
+
+	l := NewLogger("logger-print")
+	l.Print("print message")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	// Print delegates to Info
+	if e.Level != "INFO" {
+		t.Errorf("level = %q, want INFO", e.Level)
+	}
+	if e.Output != "print message" {
+		t.Errorf("output = %q, want %q", e.Output, "print message")
+	}
+	c.Destroy()
+}
+
+func TestLoggerPrintf(t *testing.T) {
+	c := CreateClient("logger-printf")
+	c.SetLogLevel(LInfo)
+
+	l := NewLogger("logger-printf")
+	l.Printf("formatted %s", "print")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "formatted print" {
+		t.Errorf("output = %q, want %q", e.Output, "formatted print")
+	}
+	c.Destroy()
+}
+
+func TestLoggerPrintln(t *testing.T) {
+	c := CreateClient("logger-println")
+	c.SetLogLevel(LInfo)
+
+	l := NewLogger("logger-println")
+	l.Println("println message")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "println message\n" {
+		t.Errorf("output = %q, want %q", e.Output, "println message\n")
+	}
+	c.Destroy()
+}
+
+func TestLoggerSetInfoDepth(t *testing.T) {
+	l := NewLogger("depth-test")
+	l.SetInfoDepth(3)
+	if l.FileInfoDepth != 3 {
+		t.Errorf("FileInfoDepth = %d, want 3", l.FileInfoDepth)
+	}
+}
+
+func TestDefaultLogger(t *testing.T) {
+	l := Default()
+	if l.Namespace != DefaultNamespace {
+		t.Errorf("namespace = %q, want %q", l.Namespace, DefaultNamespace)
+	}
+	if l.FileInfoDepth != 0 {
+		t.Errorf("FileInfoDepth = %d, want 0", l.FileInfoDepth)
+	}
+
+	// Verify Default() logger can emit entries
+	c := CreateClient(DefaultNamespace)
+	c.SetLogLevel(LInfo)
+
+	l.Info("default logger message")
+
+	e, ok := getEntry(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "default logger message" {
+		t.Errorf("output = %q, want %q", e.Output, "default logger message")
+	}
+	c.Destroy()
+}
+
+func TestLoggerPanicWithError(t *testing.T) {
+	// When the first arg is an error, Panic should re-panic with that error
+	c := CreateClient("logger-panic-err")
+	c.SetLogLevel(LPanic)
+
+	l := NewLogger("logger-panic-err")
+	testErr := errTest("test error")
+
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.Error("expected panic, got nil")
+		}
+		if err, ok := r.(errTest); ok {
+			if string(err) != "test error" {
+				t.Errorf("panic value = %q, want %q", string(err), "test error")
+			}
+		} else {
+			// The first arg was an error, so Panic should re-panic with it
+			t.Logf("panic type = %T, value = %v (implementation re-panics with original error)", r, r)
+		}
+		c.Destroy()
+	}()
+
+	l.Panic(testErr)
+}
+
+// errTest is a simple error type for testing.
+type errTest string
+
+func (e errTest) Error() string { return string(e) }

slog/handler.go

@@ -0,0 +1,165 @@
+// Package slog provides a [log/slog.Handler] that routes structured log
+// records into the log-socket broadcasting system, giving every slog-based
+// caller free WebSocket streaming and the browser viewer UI.
+package slog
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"runtime"
+	"strings"
+
+	"github.com/taigrr/log-socket/v2/log"
+)
+
+// Handler implements [slog.Handler] by converting each [slog.Record] into a
+// log-socket [log.Entry] and feeding it through the normal broadcast path.
+//
+// Attributes accumulated via [Handler.WithAttrs] are prepended to the log
+// message as key=value pairs. Groups set via [Handler.WithGroup] prefix
+// attribute keys with "group.".
+type Handler struct {
+	namespace string
+	level     slog.Level
+	attrs     []slog.Attr
+	groups    []string
+}
+
+// ensure interface compliance at compile time.
+var _ slog.Handler = (*Handler)(nil)
+
+// Option configures a [Handler].
+type Option func(*Handler)
+
+// WithNamespace sets the log-socket namespace for entries produced by this
+// handler.  If empty, [log.DefaultNamespace] is used.
+func WithNamespace(ns string) Option {
+	return func(h *Handler) {
+		h.namespace = ns
+	}
+}
+
+// WithLevel sets the minimum slog level the handler will accept.
+func WithLevel(l slog.Level) Option {
+	return func(h *Handler) {
+		h.level = l
+	}
+}
+
+// NewHandler returns a new [Handler] that writes to the log-socket broadcast
+// system.  Options may be used to set the namespace and minimum level.
+func NewHandler(opts ...Option) *Handler {
+	h := &Handler{
+		namespace: log.DefaultNamespace,
+		level:     slog.LevelDebug,
+	}
+	for _, o := range opts {
+		o(h)
+	}
+	return h
+}
+
+// Enabled reports whether the handler is configured to process records at
+// the given level.
+func (h *Handler) Enabled(_ context.Context, level slog.Level) bool {
+	return level >= h.level
+}
+
+// Handle converts r into a log-socket Entry and broadcasts it.
+func (h *Handler) Handle(_ context.Context, r slog.Record) error {
+	var b strings.Builder
+	b.WriteString(r.Message)
+
+	// Append pre-collected attrs.
+	for _, a := range h.attrs {
+		writeAttr(&b, h.groups, a)
+	}
+
+	// Append record-level attrs.
+	r.Attrs(func(a slog.Attr) bool {
+		writeAttr(&b, h.groups, a)
+		return true
+	})
+
+	file := "???"
+	if r.PC != 0 {
+		fs := runtime.CallersFrames([]uintptr{r.PC})
+		f, _ := fs.Next()
+		if f.File != "" {
+			short := f.File
+			if idx := strings.LastIndex(short, "/"); idx >= 0 {
+				short = short[idx+1:]
+			}
+			file = fmt.Sprintf("%s:%d", short, f.Line)
+		}
+	}
+
+	e := log.Entry{
+		Timestamp: r.Time,
+		Output:    b.String(),
+		File:      file,
+		Level:     slogLevelToString(r.Level),
+		Namespace: h.namespace,
+	}
+	log.Broadcast(e)
+	return nil
+}
+
+// WithAttrs returns a new Handler with the given attributes appended.
+func (h *Handler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	h2 := h.clone()
+	h2.attrs = append(h2.attrs, attrs...)
+	return h2
+}
+
+// WithGroup returns a new Handler where subsequent attributes are nested
+// under the given group name.
+func (h *Handler) WithGroup(name string) slog.Handler {
+	if name == "" {
+		return h
+	}
+	h2 := h.clone()
+	h2.groups = append(h2.groups, name)
+	return h2
+}
+
+func (h *Handler) clone() *Handler {
+	h2 := &Handler{
+		namespace: h.namespace,
+		level:     h.level,
+		attrs:     make([]slog.Attr, len(h.attrs)),
+		groups:    make([]string, len(h.groups)),
+	}
+	copy(h2.attrs, h.attrs)
+	copy(h2.groups, h.groups)
+	return h2
+}
+
+func writeAttr(b *strings.Builder, groups []string, a slog.Attr) {
+	a.Value = a.Value.Resolve()
+	if a.Equal(slog.Attr{}) {
+		return
+	}
+	b.WriteByte(' ')
+	for _, g := range groups {
+		b.WriteString(g)
+		b.WriteByte('.')
+	}
+	b.WriteString(a.Key)
+	b.WriteByte('=')
+	b.WriteString(a.Value.String())
+}
+
+func slogLevelToString(l slog.Level) string {
+	switch {
+	case l >= slog.LevelError:
+		return "ERROR"
+	case l >= slog.LevelWarn:
+		return "WARN"
+	case l >= slog.LevelInfo:
+		return "INFO"
+	default:
+		return "DEBUG"
+	}
+}

slog/handler_test.go

@@ -0,0 +1,118 @@
+package slog
+
+import (
+	"context"
+	"log/slog"
+	"testing"
+	"time"
+
+	"github.com/taigrr/log-socket/v2/log"
+)
+
+// getWithTimeout reads from a log client with a timeout to avoid hanging tests.
+func getWithTimeout(c *log.Client, timeout time.Duration) (log.Entry, bool) {
+	ch := make(chan log.Entry, 1)
+	go func() { ch <- c.Get() }()
+	select {
+	case e := <-ch:
+		return e, true
+	case <-time.After(timeout):
+		return log.Entry{}, false
+	}
+}
+
+func TestHandler_Enabled(t *testing.T) {
+	h := NewHandler(WithLevel(slog.LevelWarn))
+	if h.Enabled(context.Background(), slog.LevelInfo) {
+		t.Error("expected Info to be disabled when min level is Warn")
+	}
+	if !h.Enabled(context.Background(), slog.LevelWarn) {
+		t.Error("expected Warn to be enabled")
+	}
+	if !h.Enabled(context.Background(), slog.LevelError) {
+		t.Error("expected Error to be enabled")
+	}
+}
+
+func TestHandler_Handle(t *testing.T) {
+	c := log.CreateClient()
+	defer c.Destroy()
+	c.SetLogLevel(log.LTrace)
+
+	h := NewHandler(WithNamespace("test-ns"))
+	logger := slog.New(h)
+
+	logger.Info("hello world", "key", "value")
+
+	e, ok := getWithTimeout(c, time.Second)
+	if !ok {
+		t.Fatal("timed out waiting for log entry")
+	}
+	if e.Namespace != "test-ns" {
+		t.Errorf("namespace = %q, want %q", e.Namespace, "test-ns")
+	}
+	if e.Level != "INFO" {
+		t.Errorf("level = %q, want INFO", e.Level)
+	}
+	if e.Output == "" {
+		t.Error("output should not be empty")
+	}
+}
+
+func TestHandler_WithAttrs(t *testing.T) {
+	c := log.CreateClient()
+	defer c.Destroy()
+	c.SetLogLevel(log.LTrace)
+
+	h := NewHandler()
+	h2 := h.WithAttrs([]slog.Attr{slog.String("service", "api")})
+	logger := slog.New(h2)
+
+	logger.Info("request")
+
+	e, ok := getWithTimeout(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "request service=api" {
+		t.Errorf("output = %q, want %q", e.Output, "request service=api")
+	}
+}
+
+func TestHandler_WithGroup(t *testing.T) {
+	c := log.CreateClient()
+	defer c.Destroy()
+	c.SetLogLevel(log.LTrace)
+
+	h := NewHandler()
+	h2 := h.WithGroup("http").WithAttrs([]slog.Attr{slog.Int("status", 200)})
+	logger := slog.New(h2)
+
+	logger.Info("done")
+
+	e, ok := getWithTimeout(c, time.Second)
+	if !ok {
+		t.Fatal("timed out")
+	}
+	if e.Output != "done http.status=200" {
+		t.Errorf("output = %q, want %q", e.Output, "done http.status=200")
+	}
+}
+
+func TestSlogLevelMapping(t *testing.T) {
+	tests := []struct {
+		level slog.Level
+		want  string
+	}{
+		{slog.LevelDebug, "DEBUG"},
+		{slog.LevelInfo, "INFO"},
+		{slog.LevelWarn, "WARN"},
+		{slog.LevelError, "ERROR"},
+	}
+	for _, tt := range tests {
+		got := slogLevelToString(tt.level)
+		if got != tt.want {
+			t.Errorf("slogLevelToString(%v) = %q, want %q", tt.level, got, tt.want)
+		}
+	}
+}