diff --git a/src/device/input/button/v01_exported_test.go b/src/device/input/button/v01_exported_test.go
index 455a3b1..4d7af95 100644
--- a/src/device/input/button/v01_exported_test.go
+++ b/src/device/input/button/v01_exported_test.go
@@ -3,6 +3,8 @@ package button_test
 import (
 	"fmt"
 	"mayhem-party/src/device/input/button"
+	"os"
+	"path"
 	"testing"
 	"time"
 )
@@ -29,3 +31,41 @@ func TestV01(t *testing.T) {
 		}
 	}
 }
+
+func TestV01WithCfg(t *testing.T) {
+	d := t.TempDir()
+	p := path.Join(d, "cfg.yaml")
+	os.WriteFile(p, []byte(`
+      users:
+        bel:
+          player: 2
+      players:
+      - transformation:
+          w: t
+      - transformation:
+          w: i
+   `), os.ModePerm)
+	os.Setenv("BUTTON_PARSER_V01_CONFIG", p)
+
+	t.Run("unknown user ignored", func(t *testing.T) {
+		v01 := button.NewV01(constSrc(`{"U":"qt","Y":"w"}`))
+		got := v01.Read()
+		if len(got) != 0 {
+			t.Error(got)
+		}
+	})
+
+	t.Run("player2", func(t *testing.T) {
+		v01 := button.NewV01(constSrc(`{"U":"bel","Y":"w","N":"w"}`))
+		got := v01.Read()
+		if len(got) != 2 {
+			t.Error(got)
+		}
+		if got[0] != (button.Button{Char: 'i', Down: true}) {
+			t.Error(got[0])
+		}
+		if got[1] != (button.Button{Char: 'i', Down: false}) {
+			t.Error(got[1])
+		}
+	})
+}