Fix the checking of the used limbs

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/tests/suites/test_suite_bignum_mod_raw.function b/tests/suites/test_suite_bignum_mod_raw.function
index aaf26ca..256ec9d 100644
--- a/tests/suites/test_suite_bignum_mod_raw.function
+++ b/tests/suites/test_suite_bignum_mod_raw.function
@@ -302,9 +302,9 @@
     size_t limbs = limbs_N;
     size_t bytes = limbs * sizeof( mbedtls_mpi_uint );
 
-    TEST_ASSERT( limbs_A   <= limbs );
-    TEST_ASSERT( limbs_B   <= limbs );
-    TEST_ASSERT( limbs_res <= limbs );
+    TEST_EQUAL( limbs_A,   limbs );
+    TEST_EQUAL( limbs_B,   limbs );
+    TEST_EQUAL( limbs_res, limbs );
 
     ASSERT_ALLOC( X, limbs );