metaflac test: print out the diff of metadata when failing

Author: madah81pnz1

test/test_metaflac.sh

@@ -120,7 +120,23 @@ metaflac_test ()
 	run_metaflac $args $flacfile | filter > $testdir/out1.meta || die "ERROR running metaflac"
 	# Ignore lengths which can be affected by the version string.
 	sed "s/length:.*/length: XXX/" $testdir/out1.meta > $testdir/out.meta
-	diff -w $expect $testdir/out.meta > /dev/null 2>&1 || die "ERROR: metadata does not match expected $expect"
+	exit_code=0
+	diff -w $expect $testdir/out.meta > /dev/null 2>&1 || exit_code=$?
+	if [ "$exit_code" != 0 ] ; then
+		echo ""
+		echo "diff of expected and actual metadata:"
+		diff -w $expect $testdir/out.meta || true
+
+		# Also output a hexdump of the metadata, which can be useful in case there are in fact
+		# differences in whitespace
+		echo ""
+		echo "hexdump diff of expected and actual metadata:"
+		hd "$expect" > "$testdir/out.meta.expect.hd" || true
+		hd "$testdir/out.meta" > "$testdir/out.meta.hd" || true
+		diff "$testdir/out.meta.expect.hd" "$testdir/out.meta.hd" || true
+
+		die "ERROR: metadata does not match expected $expect"
+	fi
 	# To blindly accept (and check later): cp -f $testdir/out.meta $expect
 	echo OK
 }