diff --git a/tests/suites/test_suite_dhm.data b/tests/suites/test_suite_dhm.data
index 063c1a6016..fcfc5cf7a8 100644
--- a/tests/suites/test_suite_dhm.data
+++ b/tests/suites/test_suite_dhm.data
@@ -1,50 +1,83 @@
+Diffie-Hellman full exchange: tiny x_size
+dhm_do_dhm:10:"93450983094850938450983409623":1:10:"9345098304850938450983409622":0
+
 Diffie-Hellman parameter validation
 dhm_invalid_params:
 
+Diffie-Hellman full exchange: 5-bit, x_size=3
+dhm_do_dhm:10:"23":3:10:"5":0
+
+Diffie-Hellman full exchange: 5-bit, x_size=2
+dhm_do_dhm:10:"23":2:10:"5":0
+
 Diffie-Hellman full exchange: 5-bit #1
-dhm_do_dhm:10:"23":10:"5":0
+dhm_do_dhm:10:"23":1:10:"5":0
 
 Diffie-Hellman full exchange: 5-bit #2
-dhm_do_dhm:10:"23":10:"5":0
+dhm_do_dhm:10:"23":1:10:"5":0
 
 Diffie-Hellman full exchange: 5-bit #3
-dhm_do_dhm:10:"23":10:"5":0
+dhm_do_dhm:10:"23":1:10:"5":0
 
 Diffie-Hellman full exchange: 5-bit #4
-dhm_do_dhm:10:"23":10:"5":0
+dhm_do_dhm:10:"23":1:10:"5":0
 
 Diffie-Hellman full exchange: 5-bit #5
-dhm_do_dhm:10:"23":10:"5":0
+dhm_do_dhm:10:"23":1:10:"5":0
+
+Diffie-Hellman full exchange: 97-bit, x_size=14
+dhm_do_dhm:10:"93450983094850938450983409623":14:10:"9345098304850938450983409622":0
 
 Diffie-Hellman full exchange: 97-bit #1
-dhm_do_dhm:10:"93450983094850938450983409623":10:"9345098304850938450983409622":0
+dhm_do_dhm:10:"93450983094850938450983409623":13:10:"9345098304850938450983409622":0
 
 Diffie-Hellman full exchange: 97-bit #2
-dhm_do_dhm:10:"93450983094850938450983409623":10:"9345098304850938450983409622":0
+dhm_do_dhm:10:"93450983094850938450983409623":13:10:"9345098304850938450983409622":0
 
 Diffie-Hellman full exchange: 97-bit #3
-dhm_do_dhm:10:"93450983094850938450983409623":10:"9345098304850938450983409622":0
+dhm_do_dhm:10:"93450983094850938450983409623":13:10:"9345098304850938450983409622":0
 
 Diffie-Hellman full exchange: 97-bit #4
-dhm_do_dhm:10:"93450983094850938450983409623":10:"9345098304850938450983409622":0
+dhm_do_dhm:10:"93450983094850938450983409623":13:10:"9345098304850938450983409622":0
 
 Diffie-Hellman full exchange: 97-bit #5
-dhm_do_dhm:10:"93450983094850938450983409623":10:"9345098304850938450983409622":0
+dhm_do_dhm:10:"93450983094850938450983409623":13:10:"9345098304850938450983409622":0
+
+Diffie-Hellman full exchange: 97-bit, x_size=12
+dhm_do_dhm:10:"93450983094850938450983409623":12:10:"9345098304850938450983409622":0
+
+Diffie-Hellman full exchange: 97-bit, x_size=11
+dhm_do_dhm:10:"93450983094850938450983409623":11:10:"9345098304850938450983409622":0
+
+Diffie-Hellman full exchange: 97-bit, x_size=1 #1
+dhm_do_dhm:10:"93450983094850938450983409623":1:10:"9345098304850938450983409622":0
+
+Diffie-Hellman full exchange: 97-bit, x_size=1 #2
+dhm_do_dhm:10:"93450983094850938450983409623":1:10:"9345098304850938450983409622":0
+
+Diffie-Hellman full exchange: 97-bit, x_size=1 #3
+dhm_do_dhm:10:"93450983094850938450983409623":1:10:"9345098304850938450983409622":0
+
+Diffie-Hellman full exchange: 97-bit, x_size=1 #4
+dhm_do_dhm:10:"93450983094850938450983409623":1:10:"9345098304850938450983409622":0
+
+Diffie-Hellman full exchange: 97-bit, x_size=1 #5
+dhm_do_dhm:10:"93450983094850938450983409623":1:10:"9345098304850938450983409622":0
 
 Diffie-Hellman full exchange: 286-bit
-dhm_do_dhm:10:"93450983094850938450983409623982317398171298719873918739182739712938719287391879381271":10:"9345098309485093845098340962223981329819812792137312973297123912791271":0
+dhm_do_dhm:10:"93450983094850938450983409623982317398171298719873918739182739712938719287391879381271":36:10:"9345098309485093845098340962223981329819812792137312973297123912791271":0
 
 Diffie-Hellman trivial subgroup #1
-dhm_do_dhm:10:"23":10:"1":MBEDTLS_ERR_DHM_BAD_INPUT_DATA
+dhm_do_dhm:10:"23":1:10:"1":MBEDTLS_ERR_DHM_BAD_INPUT_DATA
 
 Diffie-Hellman trivial subgroup #2
-dhm_do_dhm:10:"23":10:"-1":MBEDTLS_ERR_DHM_BAD_INPUT_DATA
+dhm_do_dhm:10:"23":1:10:"-1":MBEDTLS_ERR_DHM_BAD_INPUT_DATA
 
 Diffie-Hellman small modulus
-dhm_do_dhm:10:"3":10:"5":MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED
+dhm_do_dhm:10:"3":1:10:"5":MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED
 
 Diffie-Hellman zero modulus
-dhm_do_dhm:10:"0":10:"5":MBEDTLS_ERR_DHM_BAD_INPUT_DATA
+dhm_do_dhm:10:"0":1:10:"5":MBEDTLS_ERR_DHM_BAD_INPUT_DATA
 
 Diffie-Hellman MPI_MAX_SIZE modulus
 dhm_make_public:MBEDTLS_MPI_MAX_SIZE:10:"5":0
diff --git a/tests/suites/test_suite_dhm.function b/tests/suites/test_suite_dhm.function
index b9dcde5804..edd96989aa 100644
--- a/tests/suites/test_suite_dhm.function
+++ b/tests/suites/test_suite_dhm.function
@@ -171,7 +171,7 @@ exit:
 /* END_CASE */
 
 /* BEGIN_CASE */
-void dhm_do_dhm( int radix_P, char *input_P,
+void dhm_do_dhm( int radix_P, char *input_P, int x_size,
                  int radix_G, char *input_G, int result )
 {
     mbedtls_dhm_context ctx_srv;
@@ -185,7 +185,7 @@ void dhm_do_dhm( int radix_P, char *input_P,
     size_t pub_cli_len = 0;
     size_t sec_srv_len;
     size_t sec_cli_len;
-    int x_size, i;
+    int i;
     mbedtls_test_rnd_pseudo_info rnd_info;
 
     mbedtls_dhm_init( &ctx_srv );
@@ -201,8 +201,7 @@ void dhm_do_dhm( int radix_P, char *input_P,
      */
     TEST_ASSERT( mbedtls_mpi_read_string( &ctx_srv.P, radix_P, input_P ) == 0 );
     TEST_ASSERT( mbedtls_mpi_read_string( &ctx_srv.G, radix_G, input_G ) == 0 );
-    x_size = mbedtls_mpi_size( &ctx_srv.P );
-    pub_cli_len = x_size;
+    pub_cli_len = mbedtls_mpi_size( &ctx_srv.P );
 
     /*
      * First key exchange