diff --git a/tests/suites/test_suite_mpi.data b/tests/suites/test_suite_mpi.data
index d88ae13..95e0d31 100644
--- a/tests/suites/test_suite_mpi.data
+++ b/tests/suites/test_suite_mpi.data
@@ -441,6 +441,33 @@
 Base test mbedtls_mpi_lsb #4
 mpi_lsb:"2000":13
 
+Test mbedtls_mpi_core_bitlen 764-bit
+mpi_core_bitlen:"941379d00fed1491fe15df284dfde4a142f68aa8d412023195cee66883e6290ffe703f4ea5963bf212713cee46b107c09182b5edcd955adac418bf4918e2889af48e1099d513830cec85c26ac1e158b52620e33ba8692f893efbb2f958b4424":764
+
+Test mbedtls_mpi_core_bitlen 0x18
+mpi_core_bitlen:"18":5
+
+Test mbedtls_mpi_core_bitlen 0x18 with leading 0 limb(s)
+mpi_core_bitlen:"00000000000000018":5
+
+Test mbedtls_mpi_core_bitlen 0x18 << 64
+mpi_core_bitlen:"180000000000000000":69
+
+Test mbedtls_mpi_core_bitlen 0x01
+mpi_core_bitlen:"1":1
+
+Test mbedtls_mpi_core_bitlen 0x0f
+mpi_core_bitlen:"f":4
+
+Test mbedtls_mpi_core_bitlen 0x10
+mpi_core_bitlen:"10":5
+
+Test mbedtls_mpi_core_bitlen 0x0a
+mpi_core_bitlen:"a":4
+
+Test mbedtls_mpi_core_bitlen: 0 (1 limb)
+mpi_core_bitlen:"0":0
+
 Test mbedtls_mpi_bitlen 764-bit
 mpi_bitlen:"941379d00fed1491fe15df284dfde4a142f68aa8d412023195cee66883e6290ffe703f4ea5963bf212713cee46b107c09182b5edcd955adac418bf4918e2889af48e1099d513830cec85c26ac1e158b52620e33ba8692f893efbb2f958b4424":764
 
diff --git a/tests/suites/test_suite_mpi.function b/tests/suites/test_suite_mpi.function
index 2528b9c..9812c56 100644
--- a/tests/suites/test_suite_mpi.function
+++ b/tests/suites/test_suite_mpi.function
@@ -665,6 +665,20 @@
 /* END_CASE */
 
 /* BEGIN_CASE */
+void mpi_core_bitlen( char *input_X, int nr_bits )
+{
+    mbedtls_mpi_uint *X = NULL;
+    size_t limbs;
+
+    TEST_EQUAL( mbedtls_test_read_mpi_core( &X, &limbs, input_X ), 0 );
+    TEST_EQUAL( mbedtls_mpi_core_bitlen( X, limbs ), nr_bits );
+
+exit:
+    mbedtls_free( X );
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
 void mpi_bitlen( char * input_X, int nr_bits )
 {
     mbedtls_mpi X;