Most of the cases provided must be tested in valgrind with trace-children and track-fds flags to check for leaks and open fds in child processes, there should be no unclosed inherited fds from parent in child:

valgrind --trace-children=yes --track-fds=yes ./minishell

And use ps aux command to check if there is zombie processes

ps aux | grep Z

Syntax:

Cases Expected Output $? Required
ls > minishell: syntax error near unexpected token `newline' 2 YES
>>> minishell: syntax error near unexpected token `>' 2 YES
<<< minishell: syntax error near unexpected token `<' 2 YES
minishell: syntax error near unexpected token `newline' 2
minishell: syntax error near unexpected token `
If Bonus:
minishell: syntax error near unexpected token `newline' 2 YES
<< minishell: syntax error near unexpected token `newline' 2 YES
>> minishell: syntax error near unexpected token `newline' 2 YES

Expander:

Cases Expected Output $? Required
$non_exist $SHELL shell> 0 YES
export test=” ”
echo $test $test $test abcd $non_exist $test 123 $test abcd 123 0 YES
export test=” abcd 123 ”
echo $test “$test” abcd 123 abcd 123 0 YES
echo $0$1230$0 minishell230minishell 0 YES
export test="ls -la”
$test ls with -la flag output 0 YES

Env:

Cases Expected Output $? Required
echo $SHLVL
./minishell
echo $SHLVL first echo will output current shell lvl second will output SHLVL + 1 0 DEBATABLE
export SHLVL=999
./minishell minishell: warning: shell level (1000) too high, resetting to 1 0 DEBATABLE
export SHLVL=-129139
./minishell
echo $SHLVL 0 0 DEBATABLE
ls -la
echo $_ ls output
-la 0 DEBATABLE

Export:

Cases Expected Output $? Required
export test1=”abcd” test2=”123” test3=”minishell” Must add test1 test2 test3 to envs 0 YES
export 1test minishell: export: `1test': not a valid identifier 1 YES
export test=”123” 1test=”test” test3=”abcd” Will add test and test3 to envs 0 YES
export test_empty
bash
export All envs except test_empty 0 YES

PIPES:

Cases Expected Output $? Required
cat cat cat echo

minishell> | 0 | YES | | cat Makefile | base64 | xxd -p | xxd -r -p | base64 --decode | Makefile code | 0 | YES | | cat Makefile | cat -e | cat -e | cat -e | cat -e | cat -e | cat -e | cat -e | cat -e | cat -e | cat -e | include Include.mk $$$$$$$$$$ SRC_DIR = src$$$$$$$$$$ OBJ_DIR = build$$$$$$$$$ … | 0 | YES | | yes yes | head -n 10000000 | wc | 10000000 10000000 40000000 | 0 | YES | | echo | echo | echo | echo | echo | echo | echo | echo | echo | echo | echo | echo | echo |
./minishell | 0 | YES | | . | .. | . | minishell> | 0 | YES | | exit 1 | exit 255 | exit 2 | minishell> | 2 | YES |

Echo:

Cases Expected Output $? Required
echo -n test testminishell> 0 YES
echo -nnnnnnn -n -nnnnnnb test -nnnnnnb testminishell> 0 YES
echo -nnnnnnn -n -nnnennE test testminishell> 0 NO
echo test test
minishell> 0 YES

Unset:

Cases Expected Output $? Required
unset USER Removes USER env 0 YES
unset USER PATH Removes USER and PATH envs 0 YES

Cd:

Cases Expected Output $? Required
cd test/ minishell: cd: No such file or directory 1 YES
cd /dev/vboxusb minishell: cd: Permission denied 1 YES
cd ../../ minishell> 0 YES
cd a b minishell: cd: too many arguments 1 YES