mpi_lt_mpi_ct test: hardcode base 16
diff --git a/tests/suites/test_suite_mpi.function b/tests/suites/test_suite_mpi.function
index 617f461..63a2509 100644
--- a/tests/suites/test_suite_mpi.function
+++ b/tests/suites/test_suite_mpi.function
@@ -588,8 +588,8 @@
 /* END_CASE */
 
 /* BEGIN_CASE */
-void mbedtls_mpi_lt_mpi_ct( int size_X, int radix_X, char * input_X,
-                            int size_Y, int radix_Y, char * input_Y,
+void mbedtls_mpi_lt_mpi_ct( int size_X, char * input_X,
+                            int size_Y, char * input_Y,
                             int input_ret, int input_err )
 {
     unsigned ret;
@@ -597,8 +597,8 @@
     mbedtls_mpi X, Y;
     mbedtls_mpi_init( &X ); mbedtls_mpi_init( &Y );
 
-    TEST_ASSERT( mbedtls_mpi_read_string( &X, radix_X, input_X ) == 0 );
-    TEST_ASSERT( mbedtls_mpi_read_string( &Y, radix_Y, input_Y ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_read_string( &X, 16, input_X ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_read_string( &Y, 16, input_Y ) == 0 );
 
     mbedtls_mpi_grow( &X, size_X );
     mbedtls_mpi_grow( &Y, size_Y );