diff --git a/tests/suites/test_suite_ecp.data b/tests/suites/test_suite_ecp.data
index 189d477f5..14099d13c 100644
--- a/tests/suites/test_suite_ecp.data
+++ b/tests/suites/test_suite_ecp.data
@@ -1027,6 +1027,8 @@ ecp_setup_negative_test #28 Invalid Curve Type
 depends_on:MBEDTLS_ECP_DP_CURVE448_ENABLED
 ecp_mod_setup:"fffffffffffffffffffffffe26f2fc17f69466a74defd8d":MBEDTLS_ECP_DP_NONE:MBEDTLS_ECP_MOD_SCALAR:MBEDTLS_ERR_ECP_BAD_INPUT_DATA
 
+# The following data be generated by random.getrandbits() in python must less than the named curves' modulus.
+# mbedtls_mpi_mod_residue_setup() can be used to check whether it satisfy the requirements.
 ecp_mul_inv #1 MBEDTLS_ECP_MOD_SCALAR(MBEDTLS_ECP_DP_SECP192R1)
 depends_on:MBEDTLS_ECP_DP_SECP192R1_ENABLED
 ecp_mod_mul_inv:"0000000000000000000000000000152d02c7e14af67fe0bf":MBEDTLS_ECP_DP_SECP192R1:MBEDTLS_ECP_MOD_SCALAR:0