ATDD shell scripting using shUnit2

acceptance_test.sh

#!/bin/sh

# Setup
SUT=../system_under_test.sh
INPUT_FILE=sample_input.txt
EXPECTED_OUTPUT_FILE=expected_output.txt
EXPECTED_STATUS_CODE=0

# The test
testStatusCodeAndResponse()
{
    response=`$SUT < $INPUT_FILE`
    assertEquals $EXPECTED_STATUS_CODE $?
    assertEquals "$(cat $EXPECTED_OUTPUT_FILE)" "$response"
}

# Load shunit2
. lib/shunit2

Using http://code.google.com/p/shunit2/ version 2.1.6