Add these tests:

tr '[==]' x
tr '[::]' x
they should fail, not get a failed assertion.

diff --git a/tests/tr/Test.pm b/tests/tr/Test.pm
index 38eaa9d..002b723 100755 (executable)
--- a/tests/tr/Test.pm
+++ b/tests/tr/Test.pm
@@ -98,6 +98,11 @@ my @tv = (
 ['ross-5', '-dc ' . q|'[:lower:]'|,            '', '', 0],
 ['ross-6', '-dc ' . q|'[:upper:]'|,            '', '', 0],
 
+# Ensure that these fail.
+# Prior to 2.0.20, each would evoke a failed assertion.
+['empty-eq', q|'[==]' x|,              '', '', 1],
+['empty-cc', q|'[::]' x|,              '', '', 1],
+
 );
 
 sub test_vector