tests: Replace "TEST_ASSERT(!memcmp ...)" by ASSERT_COMPARE

The usage of "!memcmp()" is at least not recommended
and better to use the macro dedicated for buffer
comparisons.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/suites/test_suite_chacha20.function b/tests/suites/test_suite_chacha20.function
index 968a9e9..67c8de2 100644
--- a/tests/suites/test_suite_chacha20.function
+++ b/tests/suites/test_suite_chacha20.function
@@ -28,8 +28,8 @@
      */
     TEST_ASSERT( mbedtls_chacha20_crypt( key_str->x, nonce_str->x, counter, src_str->len, src_str->x, output ) == 0 );
 
-    TEST_ASSERT( !memcmp( output, expected_output_str->x,
-                          expected_output_str->len ) );
+    ASSERT_COMPARE( output, expected_output_str->len,
+                    expected_output_str->x, expected_output_str->len );
 
     /*
      * Test the streaming API
@@ -43,8 +43,8 @@
     memset( output, 0x00, sizeof( output ) );
     TEST_ASSERT( mbedtls_chacha20_update( &ctx, src_str->len, src_str->x, output ) == 0 );
 
-    TEST_ASSERT( !memcmp( output, expected_output_str->x,
-                          expected_output_str->len ) );
+    ASSERT_COMPARE( output, expected_output_str->len,
+                    expected_output_str->x, expected_output_str->len );
 
     /*
      * Test the streaming API again, piecewise
@@ -59,8 +59,8 @@
     TEST_ASSERT( mbedtls_chacha20_update( &ctx, src_str->len - 1,
                                           src_str->x + 1, output + 1 ) == 0 );
 
-    TEST_ASSERT( !memcmp( output, expected_output_str->x,
-                          expected_output_str->len ) );
+    ASSERT_COMPARE( output, expected_output_str->len,
+                    expected_output_str->x, expected_output_str->len );
 
     mbedtls_chacha20_free( &ctx );
 }