Redesign default tree controls

uiterm/tree_regression_test.go

@@ -1,6 +1,7 @@
 package uiterm
 
 import (
+	"reflect"
 	"testing"
 	"time"
 )
@@ -15,6 +16,26 @@ func (i *cyclicItem) TreeItemStyle(fg, bg Attribute, active bool) (Attribute, At
 	return fg, bg
 }
 
+func TestTreePassesLeftRightAndBackspaceToFocusedItem(t *testing.T) {
+	item := &cyclicItem{name: "user"}
+	var received []Key
+	tree := Tree{
+		KeyListener: func(_ *Ui, _ *Tree, _ TreeItem, key Key) {
+			received = append(received, key)
+		},
+		lines: []renderedTreeItem{{Item: item}},
+	}
+	tree.uiInitialize(New(nil))
+
+	for _, key := range []Key{KeyArrowLeft, KeyArrowRight, KeyBackspace, KeyBackspace2} {
+		tree.uiKeyEvent(key)
+	}
+	want := []Key{KeyArrowLeft, KeyArrowRight, KeyBackspace, KeyBackspace2}
+	if !reflect.DeepEqual(received, want) {
+		t.Fatalf("tree keys = %v, want %v", received, want)
+	}
+}
+
 // Regression: rebuild_rec followed parent/child links with no depth limit, so
 // a cyclic channel graph recursed until the process ran out of memory. A
 // rebuild must now terminate and stay bounded.