Confusing test diagrams lua minesweeper

In the Lua minesweeper exercise I wanted to make a test for the board. I don’t know whether it is intentional but the corners of the board in the tests look the same (but aren’t) as the mines (asterisks) except for one test where the corners are plusses (the same as in all the python minesweeper tests).

Lua seems to add a border to the board. The border is inconsistent.