diff --git a/tests/suites/test_suite_mpi.data b/tests/suites/test_suite_mpi.data
index 5da83d7..8fce55a 100644
--- a/tests/suites/test_suite_mpi.data
+++ b/tests/suites/test_suite_mpi.data
@@ -1,3 +1,6 @@
+Arguments with no value
+mpi_null:
+
 Base test mpi_read_write_string #1
 mpi_read_write_string:10:"128":10:"128":100:0:0
 
diff --git a/tests/suites/test_suite_mpi.function b/tests/suites/test_suite_mpi.function
index bf4f0b3..134d220 100644
--- a/tests/suites/test_suite_mpi.function
+++ b/tests/suites/test_suite_mpi.function
@@ -8,6 +8,25 @@
  */
 
 /* BEGIN_CASE */
+void mpi_null( )
+{
+    mbedtls_mpi X, Y, Z;
+
+    mbedtls_mpi_init( &X );
+    mbedtls_mpi_init( &Y );
+    mbedtls_mpi_init( &Z );
+
+    TEST_ASSERT( mbedtls_mpi_get_bit( &X, 42 ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_lsb( &X ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_msb( &X ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_size( &X ) == 0 );
+
+exit:
+    mbedtls_mpi_free( &X );
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
 void mpi_read_write_string( int radix_X, char *input_X, int radix_A,
                             char *input_A, int output_size, int result_read,
                             int result_write )