An end-to-end test implemented in bash

acceptance_test.sh

#!/bin/bash
# the above line specifies the program used to run this script
# run like: ./acceptance_test.sh ascending 100 merge
# or:       bash acceptance_test.sh ascending 100 merge

# bash is a very easy language to make mistakes in
# let's set a few flags that help catch errors
set -e # exit on error
set -u # make the use of non-existant variables an error
set -o pipefail # propogate errors through | pipelines

# run our program. $1, $2 and $3 represent the command-line arguments passed to this script
java Assign1 $1 $2 $3 out.txt

# <() runs commands in a new shell and lets you use the output as if it were a file
# cat reads a file and prints the output
# sort -n sorts its input numerically
diff <(cat out.txt) <(cat out.txt | sort -n)