[log] NewFilterByLevel returns an error

log/filter.go

@@ -17,7 +17,8 @@ func NewFilter(next Logger, options ...Option) Logger {
 }
 
 // NewFilterByLevel wraps next and implements filtering based on a given level.
-func NewFilterByLevel(next Logger, lvl string) Logger {
+// Error is returned if level is not info, error or debug.
+func NewFilterByLevel(next Logger, lvl string) (Logger, error) {
 	var option Option
 	switch lvl {
 	case "info":
@@ -27,9 +28,9 @@ func NewFilterByLevel(next Logger, lvl string) Logger {
 	case "error":
 		option = AllowError()
 	default:
-		panic(fmt.Sprintf("Expected either \"info\", \"debug\" or \"error\" log level, given %v", lvl))
+		return nil, fmt.Errorf("Expected either \"info\", \"debug\" or \"error\" log level, given %v", lvl)
 	}
-	return NewFilter(next, option)
+	return NewFilter(next, option), nil
 }
 
 type filter struct {

log/filter_test.go

@@ -6,7 +6,6 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/stretchr/testify/assert"
 	"github.com/tendermint/tmlibs/log"
 )
 
@@ -110,13 +109,12 @@ func TestLevelContext(t *testing.T) {
 }
 
 func TestNewFilterByLevel(t *testing.T) {
-	assert := assert.New(t)
 	var logger log.Logger
 	logger = log.NewNopLogger()
-	assert.NotPanics(func() {
-		logger = log.NewFilterByLevel(logger, "info")
-	})
-	assert.Panics(func() {
-		logger = log.NewFilterByLevel(logger, "smth")
-	})
+	if _, err := log.NewFilterByLevel(logger, "info"); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := log.NewFilterByLevel(logger, "other"); err == nil {
+		t.Fatal(err)
+	}
 }