diff --git a/include/mbedtls/error.h b/include/mbedtls/error.h
index 5f24822..5b31b61 100644
--- a/include/mbedtls/error.h
+++ b/include/mbedtls/error.h
@@ -114,25 +114,44 @@
 #define MBEDTLS_ERR_ERROR_GENERIC_ERROR       -0x0001  /**< Generic error */
 #define MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED -0x006E  /**< This is a bug in the library */
 
-
-#if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_ERROR_C)
 /**
- * \brief Set a function pointer (hook) to allow for invasive testing of error
- *        code addition.
+ * \brief Combines a high-level and low-level error code together.
  *
- * This hook is used in the test infrastructure to report on errors when
- * combining two error codes of the same level.
- *
- * \param hook    hook to invasive testing function
+ *        Wrapper function for mbedtls_err_add_ext(). See that function for
+ *        more details.
  */
-void mbedtls_set_err_add_hook( void (*hook)( int, int, const char *, int ) );
-int mbedtls_err_add( int high, int low, const char *file, int line );
-#define MBEDTLS_ERR_ADD( high, low )  \
-    ( mbedtls_err_add( high, low, __FILE__, __LINE__ ) )
-#else
-#define MBEDTLS_ERR_ADD( high, low ) \
-    ( ( high ) + ( low ) )
-#endif /* MBEDTLS_TEST_HOOKS */
+#define mbedtls_error_add( high, low ) \
+        mbedtls_error_add_ext( high, low, __FILE__, __LINE__ )
+
+/**
+ * \brief Testing hook called before adding/combining two error codes together.
+ *        Only used when invasive testing is enabled via MBEDTLS_TEST_HOOKS.
+ */
+void (*mbedtls_test_hook_error_add)( int, int, const char *, int );
+
+/**
+ * \brief Combines a high-level and low-level error code together.
+ *
+ *        This function can be called directly however it is usually
+ *        called via the mbedtls_error_add macro.
+ *
+ * \note  When invasive testing is enabled via MBEDTLS_TEST_HOOKS also try to
+ *        call mbedtls_test_hook_error_add.
+ *
+ * \param high      high-level error code. See error.h for more details.
+ * \param low       low-level error code. See error.h for more details.
+ * \param file      file where this error code addition occured.
+ * \param line      line where this error code addition occured.
+ */
+static inline int mbedtls_error_add_ext( int high, int low,
+                                     const char *file, int line )
+{
+#if defined(MBEDTLS_TEST_HOOKS)
+    if( *mbedtls_test_hook_error_add != NULL )
+        ( *mbedtls_test_hook_error_add )( high, low, file, line );
+#endif
+    return( high + low );
+}
 
 /**
  * \brief Translate a mbed TLS error code into a string representation,
diff --git a/library/error.c b/library/error.c
index aaa66dd..901a369 100644
--- a/library/error.c
+++ b/library/error.c
@@ -893,22 +893,6 @@
     return( NULL );
 }
 
-#if defined(MBEDTLS_TEST_HOOKS)
-static void (*err_add_hook)( int, int, const char *, int );
-
-void mbedtls_set_err_add_hook( void (*hook)( int, int, const char *, int ) )
-{
-    err_add_hook = hook;
-}
-
-int mbedtls_err_add( int high, int low, const char *file, int line )
-{
-    if( err_add_hook != NULL )
-        (*err_add_hook)( high, low, file, line );
-    return ( high + low );
-}
-#endif /* MBEDTLS_TEST_HOOKS */
-
 void mbedtls_strerror( int ret, char *buf, size_t buflen )
 {
     size_t len;
diff --git a/library/rsa.c b/library/rsa.c
index a32d4e8..42b43ca 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -102,7 +102,7 @@
         ( D != NULL && ( ret = mbedtls_mpi_copy( &ctx->D, D ) ) != 0 ) ||
         ( E != NULL && ( ret = mbedtls_mpi_copy( &ctx->E, E ) ) != 0 ) )
     {
-        return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
+        return( mbedtls_error_add( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
     }
 
     if( N != NULL )
@@ -142,7 +142,7 @@
 cleanup:
 
     if( ret != 0 )
-        return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
+        return( mbedtls_error_add( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
 
     return( 0 );
 }
@@ -293,7 +293,7 @@
         if( ( ret = mbedtls_mpi_mul_mpi( &ctx->N, &ctx->P,
                                          &ctx->Q ) ) != 0 )
         {
-            return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
+            return( mbedtls_error_add( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
         }
 
         ctx->len = mbedtls_mpi_size( &ctx->N );
@@ -308,7 +308,7 @@
         ret = mbedtls_rsa_deduce_primes( &ctx->N, &ctx->E, &ctx->D,
                                          &ctx->P, &ctx->Q );
         if( ret != 0 )
-            return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
+            return( mbedtls_error_add( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
 
     }
     else if( d_missing )
@@ -318,7 +318,7 @@
                                                          &ctx->E,
                                                          &ctx->D ) ) != 0 )
         {
-            return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
+            return( mbedtls_error_add( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
         }
     }
 
@@ -333,7 +333,7 @@
         ret = mbedtls_rsa_deduce_crt( &ctx->P,  &ctx->Q,  &ctx->D,
                                       &ctx->DP, &ctx->DQ, &ctx->QP );
         if( ret != 0 )
-            return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
+            return( mbedtls_error_add( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
     }
 #endif /* MBEDTLS_RSA_NO_CRT */
 
@@ -461,13 +461,13 @@
         ( DQ != NULL && ( ret = mbedtls_mpi_copy( DQ, &ctx->DQ ) ) != 0 ) ||
         ( QP != NULL && ( ret = mbedtls_mpi_copy( QP, &ctx->QP ) ) != 0 ) )
     {
-        return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
+        return( mbedtls_error_add( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
     }
 #else
     if( ( ret = mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D,
                                         DP, DQ, QP ) ) != 0 )
     {
-        return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
+        return( mbedtls_error_add( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) );
     }
 #endif
 
@@ -635,8 +635,9 @@
     if( ret != 0 )
     {
         mbedtls_rsa_free( ctx );
+
         if( ( -ret & ~0x7f ) == 0 )
-            ret = MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_KEY_GEN_FAILED, ret );
+            ret = mbedtls_error_add( MBEDTLS_ERR_RSA_KEY_GEN_FAILED, ret );
         return( ret );
     }
 
@@ -769,7 +770,7 @@
     mbedtls_mpi_free( &T );
 
     if( ret != 0 )
-        return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_PUBLIC_FAILED, ret ) );
+        return( mbedtls_error_add( MBEDTLS_ERR_RSA_PUBLIC_FAILED, ret ) );
 
     return( 0 );
 }
@@ -1085,7 +1086,7 @@
     mbedtls_mpi_free( &I );
 
     if( ret != 0 && ret >= -0x007f )
-        return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_PRIVATE_FAILED, ret ) );
+        return( mbedtls_error_add( MBEDTLS_ERR_RSA_PRIVATE_FAILED, ret ) );
 
     return( ret );
 }
@@ -1198,7 +1199,7 @@
 
     /* Generate a random octet string seed */
     if( ( ret = f_rng( p_rng, p, hlen ) ) != 0 )
-        return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_RNG_FAILED, ret ) );
+        return( mbedtls_error_add( MBEDTLS_ERR_RSA_RNG_FAILED, ret ) );
 
     p += hlen;
 
@@ -1287,7 +1288,7 @@
 
             /* Check if RNG failed to generate data */
             if( rng_dl == 0 || ret != 0 )
-                return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_RNG_FAILED, ret ) );
+                return( mbedtls_error_add( MBEDTLS_ERR_RSA_RNG_FAILED, ret ) );
 
             p++;
         }
@@ -1881,7 +1882,7 @@
     /* Generate salt of length slen in place in the encoded message */
     salt = p;
     if( ( ret = f_rng( p_rng, salt, slen ) ) != 0 )
-        return( MBEDTLS_ERR_ADD( MBEDTLS_ERR_RSA_RNG_FAILED, ret ) );
+        return( mbedtls_error_add( MBEDTLS_ERR_RSA_RNG_FAILED, ret ) );
 
     p += slen;
 
diff --git a/scripts/data_files/error.fmt b/scripts/data_files/error.fmt
index 5925904..9e479bb 100644
--- a/scripts/data_files/error.fmt
+++ b/scripts/data_files/error.fmt
@@ -82,22 +82,6 @@
     return( NULL );
 }
 
-#if defined(MBEDTLS_TEST_HOOKS)
-static void (*err_add_hook)( int, int, const char *, int );
-
-void mbedtls_set_err_add_hook( void (*hook)( int, int, const char *, int ) )
-{
-    err_add_hook = hook;
-}
-
-int mbedtls_err_add( int high, int low, const char *file, int line )
-{
-    if( err_add_hook != NULL )
-        (*err_add_hook)( high, low, file, line );
-    return ( high + low );
-}
-#endif /* MBEDTLS_TEST_HOOKS */
-
 void mbedtls_strerror( int ret, char *buf, size_t buflen )
 {
     size_t len;
diff --git a/tests/suites/main_test.function b/tests/suites/main_test.function
index 7cae0da..ac00f45 100644
--- a/tests/suites/main_test.function
+++ b/tests/suites/main_test.function
@@ -284,7 +284,7 @@
 int main( int argc, const char *argv[] )
 {
 #if defined(MBEDTLS_TEST_HOOKS) && defined (MBEDTLS_ERROR_C)
-    mbedtls_set_err_add_hook( &mbedtls_test_err_add_check );
+    mbedtls_test_hook_error_add = &mbedtls_test_err_add_check;
 #endif
 
     int ret = mbedtls_test_platform_setup();