Add initialization for structures

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/tests/suites/test_suite_ecdsa.function b/tests/suites/test_suite_ecdsa.function
index 549373a..e5ae5dd 100644
--- a/tests/suites/test_suite_ecdsa.function
+++ b/tests/suites/test_suite_ecdsa.function
@@ -20,6 +20,12 @@
     size_t slen;
     unsigned char buf[42] = { 0 };
 
+    mbedtls_ecdsa_init( &ctx );
+    mbedtls_ecp_keypair_init( &key );
+    mbedtls_ecp_group_init( &grp );
+    mbedtls_ecp_point_init( &P );
+    mbedtls_mpi_init( &m );
+
     TEST_INVALID_PARAM( mbedtls_ecdsa_init( NULL ) );
     TEST_VALID_PARAM( mbedtls_ecdsa_free( NULL ) );
 
@@ -200,6 +206,12 @@
                        mbedtls_ecdsa_from_keypair( &ctx, NULL ) );
 
 exit:
+    mbedtls_ecdsa_free( &ctx );
+    mbedtls_ecp_keypair_free( &key );
+    mbedtls_ecp_group_free( &grp );
+    mbedtls_ecp_point_free( &P );
+    mbedtls_mpi_free( &m );
+
     return;
 }
 /* END_CASE */