Add cipher_set_padding() (no effect yet)

Fix pattern in tests/.gitignore along the way.
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 7c01f39..17d31e9 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -44,6 +44,7 @@
 add_test_suite(cipher cipher.camellia)
 add_test_suite(cipher cipher.des)
 add_test_suite(cipher cipher.null)
+add_test_suite(cipher cipher.padding)
 add_test_suite(ctr_drbg)
 add_test_suite(debug)
 add_test_suite(des)