diff --git a/tests/suites/test_suite_ecp.data b/tests/suites/test_suite_ecp.data
index 4748ff9..c8ed20f 100644
--- a/tests/suites/test_suite_ecp.data
+++ b/tests/suites/test_suite_ecp.data
@@ -273,6 +273,22 @@
 depends_on:POLARSSL_ECP_DP_SECP192R1_ENABLED
 ecp_fast_mod:POLARSSL_ECP_DP_SECP192R1:"1AC2D6F96A2A425E9DD1776DD8368D4BBC86BF4964E79FEA713583BF948BBEFF0939F96FB19EC48C585BDA6A2D35C750"
 
+ECP mod p521 very small
+depends_on:POLARSSL_ECP_DP_SECP521R1_ENABLED
+ecp_fast_mod:POLARSSL_ECP_DP_SECP521R1:"01"
+
+ECP mod p521 small (522 bits)
+depends_on:POLARSSL_ECP_DP_SECP521R1_ENABLED
+ecp_fast_mod:POLARSSL_ECP_DP_SECP521R1:"030000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
+
+ECP mod p521 readable
+depends_on:POLARSSL_ECP_DP_SECP521R1_ENABLED
+ecp_fast_mod:POLARSSL_ECP_DP_SECP521R1:"03FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
+
+ECP mod p521 readable with carry
+depends_on:POLARSSL_ECP_DP_SECP521R1_ENABLED
+ecp_fast_mod:POLARSSL_ECP_DP_SECP521R1:"03FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001"
+
 ECP test vectors secp192r1 rfc 5114
 depends_on:POLARSSL_ECP_DP_SECP192R1_ENABLED
 ecp_test_vect:POLARSSL_ECP_DP_SECP192R1:"323FA3169D8E9C6593F59476BC142000AB5BE0E249C43426":"CD46489ECFD6C105E7B3D32566E2B122E249ABAADD870612":"68887B4877DF51DD4DC3D6FD11F0A26F8FD3844317916E9A":"631F95BB4A67632C9C476EEE9AB695AB240A0499307FCF62":"519A121680E0045466BA21DF2EEE47F5973B500577EF13D5":"FF613AB4D64CEE3A20875BDB10F953F6B30CA072C60AA57F":"AD420182633F8526BFE954ACDA376F05E5FF4F837F54FEBE":"4371545ED772A59741D0EDA32C671112B7FDDD51461FCF32"