public function testRename() { $collection = new Collection(['A' => 'a', 'B' => 'b']); $collection->rename('A', 'C'); $this->assertEquals(['C' => 'a', 'B' => 'b'], $collection->toArray()); $collection->rename('B', 'D'); $this->assertEquals(['C' => 'a', 'D' => 'b'], $collection->toArray()); $this->expectsException(function () use($collection) { return $collection->rename('Ham', 'Chicken'); }, Exception::class, null, Exception::INVALID_PARAMETER); }