src/Document.php
public function assertExists($pointers, string $message = ''): self
    {
        $missing = collect((array) $pointers)->reject(function ($pointer) {
            return $this->has($pointer);
        })->implode(', ');

        PHPUnitAssert::assertEmpty($missing, $message ?: "Members [{$missing}] do not exist.");

        return $this;
    }
public function assertExists($pointers, string $message = ''): self
    {
        $missing = collect((array) $pointers)->reject(function ($pointer) {
            return $this->has($pointer);
        })->implode(', ');

        PHPUnitAssert::assertEmpty($missing, $message ?: "Members [{$missing}] do not exist.");

        return $this;
    }
Assert that all the provided members exist.

@param string|string[] $pointers
@param string $message
@return $this