Added testing support.

test/data/file.txt

@@ -0,0 +1,10 @@
+cat
+dog
+car
+frog
+fox
+clocks
+bash
+$300
+^$!@
+

test/data/link.txt

@@ -0,0 +1 @@
+file.txt

test/run.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+FAIL=false
+ACTION="snapshot-test"
+
+if [ -n "$1" ]; then
+	ACTION="$1"
+fi
+
+for test in "$HERE"/tests/*.sh; do
+	test_name="$(basename "$test" .sh)"
+	bash "$HERE/util/test.sh" "$ACTION" "$test_name"
+	if [ $? -ne 0 ]; then
+		FAIL=true
+	fi
+done
+
+if [ "$FAIL" = true ]; then
+	exit 1
+fi
+

test/tests/batgrep.pattern.sh

@@ -0,0 +1,4 @@
+set -e
+"$TEST_RUNNER" batgrep "ca" file.txt
+"$TEST_RUNNER" batgrep "ca" link.txt
+

test/tests/batgrep.pattern.snapshot

@@ -0,0 +1,14 @@
+────────────────────────────────────────────────────────────────────────────────
+cat
+dog
+car
+frog
+fox
+────────────────────────────────────────────────────────────────────────────────
+────────────────────────────────────────────────────────────────────────────────
+cat
+dog
+car
+frog
+fox
+────────────────────────────────────────────────────────────────────────────────

test/util/runner.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+SCRIPT="$1"
+DIR_SRC="${HERE}/../../src"
+DIR_BIN="${HERE}/../../bin"
+
+shift
+case "$TEST_RUNNER_USE" in
+	src)
+		bash "${DIR_SRC}/${SCRIPT}.sh" "$@"
+		exit $?
+		;;
+
+	bin|"")
+		"${DIR_BIN}/${SCRIPT}" "$@"
+		exit $?
+		;;
+
+	*)
+		printf "\x1B[31mInvalid TEST_RUNNER_USE variable.\x1B[0m\n"
+		printf "\x1B[31mExpects: \x1B[33msrc\x1B[31m, \x1B[33mbin\x1B[0m\n"
+		exit 1
+		;;
+esac
+

test/util/test.sh

@@ -0,0 +1,86 @@
+#!/usr/bin/env bash
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+RUNNER="${HERE}/runner.sh"
+TEST_DATA="${HERE}/../data"
+
+# Test data.
+TEST_ID="$2"
+TEST_SCRIPT="${HERE}/../tests/${TEST_ID}.sh"
+TEST_OUT="$(mktemp)"
+TEST_OUT2="$(mktemp)"
+TEST_OUT_SNAPSHOT="${HERE}/../tests/${TEST_ID}.snapshot"
+
+# Functions.
+pass() {
+	printf "\x1B[33mTest [%s]:\x1B[32m %s\x1B[0m\n" "$TEST_ID" "Passed"
+	exit 0
+}	
+
+fail() {
+	printf "\x1B[33mTest [%s]:\x1B[31m %s\x1B[0m\n" "$TEST_ID" "Failed"
+	case "$1" in
+		EXIT)
+			local c="in packaged script"
+			if [ "$2" = "bin" ]; then
+				c="in source script"
+			fi
+
+			printf "\x1B[33mError (%s):\x1B[0m\n" "$c"
+			bat --style=numbers -
+			;;
+
+		DIFF)
+			printf "\x1B[31m%s\x1B[0m\n" "$1"
+			printf "\x1B[33mDifference:\x1B[0m\n"
+			bat --style=plain -l diff -
+			;;
+	esac
+	exit 1
+}
+
+run() {
+	({
+		cd "$TEST_DATA"
+		export TEST_RUNNER="$RUNNER"
+		export TEST_RUNNER_USE="$1"
+		bash "$TEST_SCRIPT" >"$2" 2>&1 || exit $?
+	}) || fail EXIT "$1" < "$2"
+}
+
+# Run the test command.
+case "$1" in
+	snapshot-generate) {
+		run src "$TEST_OUT"
+		mv "$TEST_OUT" "$TEST_OUT_SNAPSHOT"
+		printf "\x1B[33mTest [%s]:\x1B[35m %s\x1B[0m\n" "$1" "Updated"
+	};;
+		
+	snapshot-test) {
+		run src "$TEST_OUT"
+		SNAPSHOT_DIFF="$(diff "$TEST_OUT" "$TEST_OUT_SNAPSHOT")"
+		if [ -z "$SNAPSHOT_DIFF" ]; then
+			pass
+		else
+			fail DIFF "The current revision does not match the snapshot."
+		fi
+	};;
+
+	consistency-test) {
+		run src "$TEST_OUT"
+		run bin "$TEST_OUT2"
+		SNAPSHOT_DIFF="$(diff "$TEST_OUT" "$TEST_OUT2")"
+		if [ -z "$SNAPSHOT_DIFF" ]; then
+			pass
+		else
+			fail DIFF "The current built and executed scripts act differently."
+		fi
+	};;
+
+	*) {
+		printf "\x1B[31mUnknown subcommand.\x1B[0m\n"
+		printf " - \x1B[33msnapshot-generate\x1B[0m  -- generate new snapshots\n"
+		printf " - \x1B[33msnapshot-test\x1B[0m      -- compare current revision with snapshots\n"
+		printf " - \x1B[33mconsistency-test\x1B[0m   -- compare current revision packaged and loose scripts\n"
+	};;
+esac
+