Added tests for mbedtls_rsa_rsassa_pss_sign_ext()

- added some invalid param tests in test_suite_rsa
- added functional tests in test_suite_pkcs1_v21

Signed-off-by: Cédric Meuter <cedric.meuter@gmail.com>
diff --git a/tests/suites/test_suite_pkcs1_v21.function b/tests/suites/test_suite_pkcs1_v21.function
index c28cf08..b928e80 100644
--- a/tests/suites/test_suite_pkcs1_v21.function
+++ b/tests/suites/test_suite_pkcs1_v21.function
@@ -159,7 +159,18 @@
                                          hash_result, output ) == result );
     if( result == 0 )
     {
+        TEST_ASSERT( mbedtls_test_hexcmp( output, result_str->x,
+                                          ctx.len, result_str->len ) == 0 );
+    }
 
+    info.buf = rnd_buf->x;
+    info.length = rnd_buf->len;
+
+    TEST_ASSERT( mbedtls_rsa_rsassa_pss_sign_ext( &ctx, &mbedtls_test_rnd_buffer_rand,
+                                                  &info, digest, 0, hash_result,
+                                                  MBEDTLS_RSA_SALT_LEN_ANY, output ) == result );
+    if( result == 0 )
+    {
         TEST_ASSERT( mbedtls_test_hexcmp( output, result_str->x,
                                           ctx.len, result_str->len ) == 0 );
     }