diff --git a/library/std/src/io/tests.rs b/library/std/src/io/tests.rs index f64f034cce779..fd962b0415c7d 100644 --- a/library/std/src/io/tests.rs +++ b/library/std/src/io/tests.rs @@ -811,13 +811,17 @@ fn read_to_end_error() { } #[test] -// Miri does not support signalling OOM -#[cfg_attr(miri, ignore)] -// 64-bit only to be sure the allocator will fail fast on an impossible to satisfy size -#[cfg(target_pointer_width = "64")] fn try_oom_error() { - let mut v = Vec::::new(); - let reserve_err = v.try_reserve(isize::MAX as usize - 1).unwrap_err(); + use alloc::alloc::Layout; + use alloc::collections::{TryReserveError, TryReserveErrorKind}; + + // We simulate a `Vec::try_reserve` error rather than attempting a huge size for real. This way + // we're not subject to the whims of optimization that might skip the actual allocation, and it + // also works for 32-bit targets and miri that might not OOM at all. + let layout = Layout::new::(); + let kind = TryReserveErrorKind::AllocError { layout, non_exhaustive: () }; + let reserve_err = TryReserveError::from(kind); + let io_err = io::Error::from(reserve_err); assert_eq!(io::ErrorKind::OutOfMemory, io_err.kind()); }