I read the kata wrong so I've first converted to binary and then calculated the result :>

What's going on here 😳

The final result has no spaces, so no, it's not longer than 140 chars. Not a kata issue.

If the final result is longer than 140 chars it must return false

The final result (#CodeWars) not the input should be less than 140 chars.

I think there is an issue with a basic test ("testThatSomethingShouldHappen") request. The function should reject strings longer than 140 or equal chars.
This request wishes to see the string "#CodeWars" but the input string is larger than 140 chars:

$this->assertSame('#CodeWars', generateHashtag('Code' . str_repeat(' ', 140) . 'wars'));

I'm using PHP on this Kata