How to check app response from localhost with only 1 terminal

Solution

.ONESHELL:
test:
    @echo "[ - ] testing app"
    @kill -9 $$(lsof -t -i tcp:5000)
    @flask run 1>/dev/null 2>/dev/null &
    @sleep 2
    @cd ../sender
    @python main.py > received.txt
    @if cmp -s -- received.txt expected.txt; \
    then echo "[ > ] PASS 🥳 "; else echo "[ - ] ERROR 😵"; fi
    @cd - 1>/dev/null 2>/dev/null