Functional\Tests\GroupTest::testExceptionIsThrownWhenCallbacksReturnsInvalidKey PHP Метод

    public function testExceptionIsThrownWhenCallbacksReturnsInvalidKey()
    {
        $array = ['v1', 'v2', 'v3', 'v4', 'v5', 'v6'];
        $keyMap = [true, 1, -1, 2.1, 'str', null];
        $fn = function ($v, $k, $collection) use(&$keyMap) {
            return $keyMap[$k];
        };
        $result = [1 => [0 => 'v1', 1 => 'v2'], -1 => [2 => 'v3'], 2 => [3 => 'v4'], 'str' => [4 => 'v5'], null => [5 => 'v6']];
        $this->assertSame($result, group($array, $fn));
        $this->assertSame($result, group(new ArrayIterator($array), $fn));
        $invalidTypes = ['resource' => stream_context_create(), 'object' => new \stdClass(), 'array' => []];
        foreach ($invalidTypes as $type => $value) {
            $keyMap = [$value];
            try {
                group(['v1'], $fn);
                $this->fail(sprintf('Error expected for array key type "%s"', $type));
            } catch (\Exception $e) {
                $this->assertSame(sprintf('Functional\\group(): callback returned invalid array key of type "%s". Expected NULL, string, integer, double or boolean', $type), $e->getMessage());
            }
        }
    }