Increase test coverage by adding AES and CAMELLIA empty buffer tests

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/tests/suites/test_suite_cipher.aes.data b/tests/suites/test_suite_cipher.aes.data
index 6293408..4dbdd52 100644
--- a/tests/suites/test_suite_cipher.aes.data
+++ b/tests/suites/test_suite_cipher.aes.data
@@ -1062,6 +1062,10 @@
 depends_on:MBEDTLS_AES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_CIPHER_PADDING_PKCS7
 enc_dec_buf_multipart:MBEDTLS_CIPHER_AES_192_CBC:192:16:16:-1:16:16:0:32
 
+AES-256 CBC - Decrypt empty buffer
+depends_on:MBEDTLS_AES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_CIPHER_PADDING_PKCS7
+dec_empty_buf:MBEDTLS_CIPHER_AES_256_CBC:0:0
+
 AES-256 CBC - Encrypt and decrypt 0 bytes with PKCS7 padding
 depends_on:MBEDTLS_AES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_CIPHER_PADDING_PKCS7
 enc_dec_buf:MBEDTLS_CIPHER_AES_256_CBC:"AES-256-CBC":256:0:-1