llog: tests and examples

Signed-off-by: Chris Koch <[email protected]>

llog/default2_test.go

@@ -0,0 +1,20 @@
+// Copyright 2024 the u-root Authors. All rights reserved
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package llog_test
+
+import (
+	"log/slog"
+
+	"github.com/u-root/uio/llog"
+)
+
+func ExampleDefault_withtime() {
+	l := llog.Default()
+	l.Infof("An INFO level string")
+	l.Debugf("A DEBUG level that does not appear")
+
+	l.Level = llog.Level(slog.LevelDebug)
+	l.Debugf("A DEBUG level that appears")
+}

llog/default_test.go

@@ -0,0 +1,36 @@
+// Copyright 2024 the u-root Authors. All rights reserved
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package llog_test
+
+import (
+	"log"
+	"log/slog"
+	"os"
+
+	"github.com/u-root/uio/llog"
+)
+
+func ExampleDefault() {
+	// Example is reproducible without date/time displayed.
+	log.SetFlags(0)
+	// Examples only go out to stdout.
+	log.SetOutput(os.Stdout)
+
+	l := llog.Default()
+	l.Infof("An INFO level string")
+	l.Debugf("A DEBUG level that does not appear")
+
+	l.Level = llog.Level(slog.LevelDebug)
+	l.Debugf("A DEBUG level that appears")
+
+	l.Warnf("I'm warning you")
+	l.Errorf("This is going to error")
+
+	// Output:
+	// INFO An INFO level string
+	// DEBUG A DEBUG level that appears
+	// WARN I'm warning you
+	// ERROR This is going to error
+}

llog/example_test.go

@@ -0,0 +1,26 @@
+// Copyright 2024 the u-root Authors. All rights reserved
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package llog_test
+
+import (
+	"flag"
+	"log/slog"
+
+	"github.com/u-root/uio/llog"
+)
+
+func someFunc(v llog.Printf) {
+	v("logs at the given level %s", "foo")
+}
+
+func Example() {
+	l := llog.Default()
+	// If -v is set, l.Level becomes slog.LevelDebug.
+	l.Level.RegisterDebugFlag(flag.CommandLine, "v")
+	flag.Parse()
+
+	someFunc(l.Debugf)
+	someFunc(l.Printf(slog.LevelWarn))
+}

llog/levellog.go

@@ -70,7 +70,7 @@ func SinkFor(p Printf) Sink {
 		// Prepend log level.
 		format = "%s " + format
 		args = append([]any{level}, args...)
-		p(format, args)
+		p(format, args...)
 	}
 }
 
@@ -88,7 +88,7 @@ type Logger struct {
 // uses l as the default log level.
 //
 // Logs with level >= l will be printed using p.
-func New(p Printf, l Level) *Logger {
+func New(l Level, p Printf) *Logger {
 	return &Logger{
 		Sink:  SinkFor(p),
 		Level: l,
@@ -97,10 +97,10 @@ func New(p Printf, l Level) *Logger {
 
 // Printf returns a Printf that can be passed around to log at the given level.
 func (l *Logger) Printf(level slog.Level) Printf {
+	if l == nil || l.Sink == nil {
+		return func(fmt string, args ...any) {}
+	}
 	return func(fmt string, args ...any) {
-		if l == nil {
-			return
-		}
 		l.Logf(level, fmt, args...)
 	}
 }

llog/llog_test.go

@@ -0,0 +1,174 @@
+// Copyright 2024 the u-root Authors. All rights reserved
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package llog
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"log/slog"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+func TestLevelFlag(t *testing.T) {
+	for _, tt := range []struct {
+		args []string
+		want Level
+	}{
+		{
+			args: []string{"-level=4"},
+			want: Level(slog.LevelWarn),
+		},
+		{
+			args: []string{},
+			want: Level(slog.LevelInfo),
+		},
+	} {
+		f := flag.NewFlagSet("", flag.ContinueOnError)
+
+		var v Level
+		v.RegisterLevelFlag(f, "level")
+		_ = f.Parse(tt.args)
+
+		if v != tt.want {
+			t.Errorf("Parse(%#v) = %v, want %v", tt.args, v, tt.want)
+		}
+	}
+
+	for _, tt := range []struct {
+		args []string
+		want Level
+		err  error
+	}{
+		{
+			args: []string{"-v"},
+			want: Level(slog.LevelWarn),
+		},
+		{
+			args: []string{},
+			want: Level(slog.LevelInfo),
+		},
+		{
+			args: []string{"-v=true"},
+			want: Level(slog.LevelWarn),
+		},
+		{
+			args: []string{"-v=true", "-v=false"},
+			want: Level(slog.LevelWarn),
+		},
+		{
+			args: []string{"-v=foobar"},
+			want: Level(slog.LevelInfo),
+			err:  strconv.ErrSyntax,
+		},
+	} {
+		f := flag.NewFlagSet("", flag.ContinueOnError)
+
+		var v Level
+		v.RegisterVerboseFlag(f, "v", slog.LevelWarn)
+		// Parse doesn't use %w.
+		if err := f.Parse(tt.args); err != tt.err && err != nil && !strings.Contains(err.Error(), tt.err.Error()) {
+			t.Errorf("Parse(%#v) = %v, want %v", tt.args, err, tt.err)
+		}
+		if v != tt.want {
+			t.Errorf("Parse(%#v) = %v, want %v", tt.args, v, tt.want)
+		}
+	}
+
+	for _, tt := range []struct {
+		args []string
+		want Level
+		err  error
+	}{
+		{
+			args: []string{"-v"},
+			want: Level(slog.LevelDebug),
+		},
+		{
+			args: []string{},
+			want: Level(slog.LevelInfo),
+		},
+		{
+			args: []string{"-v=true"},
+			want: Level(slog.LevelDebug),
+		},
+		{
+			args: []string{"-v=true", "-v=false"},
+			want: Level(slog.LevelDebug),
+		},
+		{
+			args: []string{"-v=foobar"},
+			want: Level(slog.LevelInfo),
+			err:  strconv.ErrSyntax,
+		},
+	} {
+		f := flag.NewFlagSet("", flag.ContinueOnError)
+
+		var v Level
+		v.RegisterDebugFlag(f, "v")
+		// Parse doesn't use %w.
+		if err := f.Parse(tt.args); err != tt.err && err != nil && !strings.Contains(err.Error(), tt.err.Error()) {
+			t.Errorf("Parse(%#v) = %v, want %v", tt.args, err, tt.err)
+		}
+		if v != tt.want {
+			t.Errorf("Parse(%#v) = %v, want %v", tt.args, v, tt.want)
+		}
+	}
+}
+
+func TestNilLogger(t *testing.T) {
+	for _, l := range []*Logger{nil, {}} {
+		// Test that none of this panics.
+		l.Printf(slog.LevelDebug)("nothing")
+		l.Debugf("nothing")
+		l.Infof("nothing")
+		l.Warnf("nothing")
+		l.Errorf("nothing")
+		l.Logf(slog.LevelDebug, "nothing")
+	}
+}
+
+func TestLog(t *testing.T) {
+	var s strings.Builder
+	l := New(Level(slog.LevelDebug), func(format string, args ...any) {
+		fmt.Fprintf(&s, format+"\n", args...)
+	})
+
+	l.Printf(slog.LevelDebug)("nothing")
+	l.Debugf("nothing")
+	l.Infof("nothing")
+	l.Warnf("nothing")
+	l.Errorf("nothing")
+	l.Logf(slog.LevelDebug, "nothing")
+
+	want := `DEBUG nothing
+DEBUG nothing
+INFO nothing
+WARN nothing
+ERROR nothing
+DEBUG nothing
+`
+	if got := s.String(); got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}
+
+func TestDefaults(t *testing.T) {
+	var s strings.Builder
+	log.SetOutput(&s)
+	log.SetFlags(0)
+
+	l := Debug()
+	l.Debugf("foobar")
+	want := "DEBUG foobar\n"
+	if got := s.String(); got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	l = Test(t)
+	l.Debugf("more foobar")
+}