Throw exception when opening menu with no items. Resolves #130

Author: AydinHassan

src/CliMenu.php

@@ -486,6 +486,10 @@ public function open() : void
         if ($this->isOpen()) {
             return;
         }
+        
+        if (count($this->items) === 0) {
+            throw new \RuntimeException('Menu must have at least 1 item before it can be opened');
+        }
 
         $this->configureTerminal();
         $this->open = true;

test/CliMenuTest.php

@@ -359,11 +359,19 @@ public function testThrowsExceptionIfTerminalIsNotValidTTY() : void
             ->method('isInteractive')
             ->willReturn(false);
 
-        $menu = new CliMenu('PHP School FTW', [], $terminal);
+        $menu = new CliMenu('PHP School FTW', [new StaticItem('One')], $terminal);
 
         $menu->open();
     }
 
+    public function testOpenThrowsExceptionIfNoItemsInMenu() : void
+    {
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Menu must have at least 1 item before it can be opened');
+        
+        (new CliMenu('PHP School FTW', [], $this->terminal))->open();
+    }
+
     public function testGetTerminal() : void
     {
         $menu = new CliMenu('PHP School FTW', []);