Check out this BF interpreter:

https://gkucmierz.github.io/brainfuck-interpreter

You can see HEX output in this.

"Hello World!" has 12 chars, your code has 13 . operations. This solution cannot be correct.

Print the terms of the sum, they're wrong.

Have you read the error message? It should be obvious what "expected X, instead got Y" means.

Now, that problem is solved but you still need to address this point:

... or says Hello, World! if name is not given (or passed as an empty String).

Read the error message:

Failed asserting that two strings are equal.
Expected: 'Hello, World!'
Actual  : 'Hello, !'

Don't change the sample tests to make your code "work", it's the other way around.

And what get you that idea? Please, use the starting code as it is, don't change the function's name or create a class, it won't work.

Stop creating issues, your code is wrong, read the description again, that exact case is explained there.

Your code is wrong in many ways.

1. Syntax error in line 5, why there is }?
2. You're supposed to use default argument when there isn't any argument given.
3. You're supposed to return the name in title case, and there should be a space between name and Hello

Post your code here, mark your post as having spoiler content.

This is the initial code:

function hello($name = ''): string { //you changed this line
  return ;
}

You must have renamed the function to something else. The tests are ok. Click reset.