Fix infinite loop when no selectable items.

src/CliMenu.php

@@ -283,7 +283,17 @@ protected function moveSelectionVertically(string $direction) : void
     {
         $itemKeys = array_keys($this->items);
 
+        $increments = 0;
+
         do {
+            $increments++;
+
+            if ($increments > count($itemKeys)) {
+                //full cycle detected, there must be no selected items
+                //in the menu, so stop trying to select one.
+                return;
+            }
+
             $direction === 'UP'
                 ? $this->selectedItem--
                 : $this->selectedItem++;

test/CliMenuTest.php

@@ -920,6 +920,20 @@ public function testGetSelectedItemThrowsExceptionIfNoSelectedItem() : void
         $menu->getSelectedItem();
     }
 
+    public function testMenuCanOpenAndFunctionWithoutAnySelectableItems() : void
+    {
+        $this->terminal->expects($this->exactly(3))
+            ->method('read')
+            ->willReturn("\033[B", "\033[B", 'Q');
+        $menu = new CliMenu('PHP School FTW', [new StaticItem('One')], $this->terminal);
+        $menu->addCustomControlMapping('Q', function (CliMenu $menu) {
+            $menu->close();
+        });
+        $menu->open();
+
+        self::assertCount(1, $menu->getItems());
+    }
+
     private function getTestFile() : string
     {
         return sprintf('%s/res/%s.txt', __DIR__, $this->getName());