From d531948c0223754c0c5bbb40bfbff19b52a2f024 Mon Sep 17 00:00:00 2001 From: Kyle Thompson Date: Fri, 14 Aug 2026 18:57:01 -0400 Subject: [PATCH] add warning about default test order causing problems with MPI --- docs/command-line.md | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/docs/command-line.md b/docs/command-line.md index cbb3449efe..e7e25b8430 100644 --- a/docs/command-line.md +++ b/docs/command-line.md @@ -457,6 +457,10 @@ Using `random-device` asks for `std::random_device` to be used instead. If your implementation provides working `std::random_device`, it should be preferred to using `time`. Catch2 uses `std::random_device` by default. +> [!WARNING] +> You should not use this option when launching Catch2 tests on multiples processes that require synchronous communication, +> (e.g., Message Passing Interface (MPI) code), +> because the test order of execution will **not** be indentical on all processes. ## Identify framework and version according to the libIdentify standard