From bce146da4a4cebd09a5f48d4fd243e030569dcd0 Mon Sep 17 00:00:00 2001
From: Brian Smith <brian@briansmith.org>
Date: Fri, 21 Oct 2022 09:34:31 -0700
Subject: [PATCH] Tests: Use custom tests to verify operations on empty slices
 are no-ops.

Modify the custom tests so that they would have detected and prevented
the issue fixed in https://github.com/rust-random/getrandom/pull/298.
---
 tests/custom_common/mod.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tests/custom_common/mod.rs b/tests/custom_common/mod.rs
index 203b26fa..c84c6df3 100644
--- a/tests/custom_common/mod.rs
+++ b/tests/custom_common/mod.rs
@@ -10,6 +10,9 @@ pub fn len7_err() -> Error {
 }
 
 fn super_insecure_rng(buf: &mut [u8]) -> Result<(), Error> {
+    // `getrandom` guarantees it will not call any implementation if the output
+    // buffer is empty.
+    assert!(!buf.is_empty());
     // Length 7 buffers return a custom error
     if buf.len() == 7 {
         return Err(len7_err());