Add hb-diff-filter-failures

test/shaping/hb-diff-filter-failures

+#!/usr/bin/python
+
+import sys
+
+red_color = '\033[41;37;1m'
+green_color = '\033[42;37;1m'
+end_color = '\033[m'
+
+def filter_failures (f):
+	for l in f:
+		if l[0] in '-+':
+			sys.stdout.writelines (l)
+			continue
+
+
+def open_file (f):
+	if f == '-':
+		return sys.stdin
+	return file (f)
+
+if __name__ == '__main__':
+
+	if len (sys.argv) == 1:
+		print "Usage: %s FILE..." % sys.argv[0]
+		sys.exit (1)
+
+	for s in sys.argv[1:]:
+		filter_failures (open_file (s))