Use byte differences for sample matching

tests/samples_match.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+# Copyright 2022 Mycroft AI Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# -----------------------------------------------------------------------------
+#
+# Uses cmp to compare byte differences between two samples.
+# Exits with an error if differences exceed a threshold.
+#
+set -o pipefail
+
+if [ -z "$2" ]; then
+    echo 'Usage: samples_match.sh WAV1 WAV2 [threshold]';
+    exit 1
+fi
+
+wav1="$1"
+wav2="$2"
+threshold="${3:-5000}"
+
+bytes_different="$(cmp -l "${wav1}" "${wav2}" | wc -l)"
+
+if (( ${bytes_different} > ${threshold} )); then
+    echo "Samples differ too much (${bytes_different} > ${threshold})";
+    exit 1;
+fi
+
+echo 'OK'