Hello José,
Welcome to ExcelFox

I have two ways that I overcome these sorts of problems. I leave the cell as standard format , not text format.
Then
Either
Leave a space, before writing
Or
Write what I want as a formula.

So for your example, in a cell with standard format I would write exactly either of these two texts, ( remember the first one has a space before the - )
Code:
 - TestTest. 

="- TestTest."
I don’t know if there are any other ways to achieve what you want. I expect there might be, but I don’t know about them. Possibly someone else might have an idea later

Alan