fork process in a BATS test script

fork_in_test.bats

# Aimed to test running script status.
# In this script, check the sleep process which is forked during a test script.

@test "count_process_extshell" {
    echo "#!/bin/bash" > fork_shell.sh
    echo "" >> fork_shell.sh
    echo "sleep 1 &" >> fork_shell.sh
    echo "ps ax | grep -E \"[0-9] sleep\" | wc -l" >> fork_shell.sh
    
    ret=$(bash fork_shell.sh)
    [ "$ret" = "1" ]

    rm fork_shell.sh
}

@test "count_process_in_bats" {
    sleep 1 &
    ret=$(ps ax | grep -E "[0-9] sleep" | wc -l)
    [ "$ret" = "1" ]
    wait
}

@test "count_process_wait" {
    sleep 1 &
    ret=$(ps ax | grep -E "[0-9] sleep" | wc -l)
    [ "$ret" = "1" ]
    wait
    ret=$(ps ax | grep -E "[0-9] sleep" | wc -l)
    [ "$ret" = "0" ]
}

@test "count_process_kill" {
    sleep 1 &
    psnum=$(ps ax | grep -E "[0-9] sleep" | awk '{print $1}')
    ret=$(ps ax | grep -E "[0-9] sleep" | wc -l)
    [ "$ret" = "1" ]
    kill $psnum
    ret=$(ps ax | grep -E "[0-9] sleep" | wc -l)
    [ "$ret" = "0" ]
    wait
}

$ cat fork_shell.sh
#!/bin/bash

sleep 1 &
ps ax | grep -E "[0-9] sleep" | wc -l

$ bats -t fork_in_test.bats
1..4
ok 1 count_process_extshell
ok 2 count_process_in_bats
ok 3 count_process_wait
ok 4 count_process_kill