Make psa_get_mac_output_length testable and test it

Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
diff --git a/library/psa_crypto_invasive.h b/library/psa_crypto_invasive.h
index be127d9..99156de 100644
--- a/library/psa_crypto_invasive.h
+++ b/library/psa_crypto_invasive.h
@@ -35,6 +35,7 @@
 #endif
 
 #include "psa/crypto.h"
+#include "common.h"
 
 #include "mbedtls/entropy.h"
 
@@ -76,4 +77,10 @@
     void (* entropy_free )( mbedtls_entropy_context *ctx ) );
 #endif /* !defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) */
 
+#if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_PSA_CRYPTO_C)
+psa_status_t psa_get_mac_output_length( psa_algorithm_t algorithm,
+                                        psa_key_type_t key_type,
+                                        size_t *length );
+#endif /* MBEDTLS_TEST_HOOKS && MBEDTLS_PSA_CRYPTO_C */
+
 #endif /* PSA_CRYPTO_INVASIVE_H */