Split assignment and assert check into seperate lines in tests
diff --git a/tests/suites/test_suite_x509write.function b/tests/suites/test_suite_x509write.function
index 0cea5f9..2eb270f 100644
--- a/tests/suites/test_suite_x509write.function
+++ b/tests/suites/test_suite_x509write.function
@@ -117,8 +117,8 @@
 
     f = fopen( cert_check_file, "r" );
     TEST_ASSERT( f != NULL );
-    TEST_ASSERT( ( olen = fread( check_buf, 1, sizeof(check_buf), f ) ) <
-                 sizeof(check_buf) );
+    olen = fread( check_buf, 1, sizeof(check_buf), f );
+    TEST_ASSERT( olen < sizeof(check_buf) );
     fclose( f );
 
     TEST_ASSERT( olen >= pem_len - 1 );