value with space after:${ A_NAME:-Korben Dallas }, value with space before:${ A_NAME:-  Leeloo Dallas}.
value without spaces:${A_NAME:-Ruby Rhod}, value with non alplha character:${   A_NAME:-Jean-Baptiste Emanuel Zorg @£$   }.
Empty default value:${A_NAME:-}.
White spaces as default value:${A_NAME:-            }.
Invalid expression1:${A_NAME :-fds}
Invalid expression2:${A_NAME@£rew:-fds}.
Normal variable with spaces:${     A_NAME     }.
Normal variable:${A_NAME}.
