/**
* @inheritdoc
*/
public function add($key, Equatable $value)
{
if ($this->containsKey($key)) {
throw InRangeException::keyInRange($key);
}
$items = $this->items;
$items[$key] = $value;
return new static($items);
}
/**
* @test
*/
public function it_creates_a_keyInRange_exception()
{
$exception = InRangeException::keyInRange(0);
$this->assertInstanceOf(InRangeException::class, $exception);
$this->assertSame('Collection already contains the key 0', $exception->getMessage());
}