diff --git a/cmd/dex/serve.go b/cmd/dex/serve.go
index b39354ec0b..456e07f6a9 100644
--- a/cmd/dex/serve.go
+++ b/cmd/dex/serve.go
@@ -520,11 +520,11 @@ func newLogger(level slog.Level, format string) (*slog.Logger, error) {
 	var handler slog.Handler
 	switch strings.ToLower(format) {
 	case "", "text":
-		slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
+		handler = slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
 			Level: level,
 		})
 	case "json":
-		slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{
+		handler = slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{
 			Level: level,
 		})
 	default:
diff --git a/cmd/dex/serve_test.go b/cmd/dex/serve_test.go
new file mode 100644
index 0000000000..9e214480d3
--- /dev/null
+++ b/cmd/dex/serve_test.go
@@ -0,0 +1,29 @@
+package main
+
+import (
+	"log/slog"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewLogger(t *testing.T) {
+	t.Run("JSON", func(t *testing.T) {
+		logger, err := newLogger(slog.LevelInfo, "json")
+		require.NoError(t, err)
+		require.NotEqual(t, (*slog.Logger)(nil), logger)
+	})
+
+	t.Run("Text", func(t *testing.T) {
+		logger, err := newLogger(slog.LevelError, "text")
+		require.NoError(t, err)
+		require.NotEqual(t, (*slog.Logger)(nil), logger)
+	})
+
+	t.Run("Unknown", func(t *testing.T) {
+		logger, err := newLogger(slog.LevelError, "gofmt")
+		require.Error(t, err)
+		require.Equal(t, "log format is not one of the supported values (json, text): gofmt", err.Error())
+		require.Equal(t, (*slog.Logger)(nil), logger)
+	})
+}