'b', 'b' => 'c', 'c' => 'd'], ['b' => 'a', 'c' => 'b', 'd' => 'c'], ], [ [1 => 0, 2 => 1, 3 => 2, 4 => 3, 5 => 4, 6 => 5, 7 => 6, 8 => 7, 9 => 8, 10 => 9], [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], ], ]; } public function testFlipThrowsForNonArrayKeyValues(): void { $this->expectException(Exception\InvariantViolationException::class); $this->expectExceptionMessage('Expected all values to be of type array-key, value of type (resource) provided.'); Arr\flip([STDOUT]); } }