4, 'b' => 5], 'b'], [0, [0, 1], 0], [1, [1, 2], 0], [null, [null], 0], ]; } public function testAtThrowsForOutOfBoundKey(): void { $this->expectException(Exception\InvariantViolationException::class); $this->expectExceptionMessage('key (5) was out-of-bound'); Arr\at([], 5); } }