1 files changed, 20 insertions, 6 deletions

diff --git a/lib/std/testing.zig b/lib/std/testing.zig
index 4e43413d28..8fa5fb68f8 100644
--- a/lib/std/testing.zig
+++ b/lib/std/testing.zig
@@ -534,18 +534,27 @@ test {
 ///
 /// Any relevant state shared between runs of `test_fn` *must* be reset within `test_fn`.
 ///
-/// Expects that the `test_fn` has a deterministic number of memory allocations
-/// (an error will be returned if non-deterministic allocations are detected).
-///
 /// The strategy employed is to:
 /// - Run the test function once to get the total number of allocations.
 /// - Then, iterate and run the function X more times, incrementing
 ///   the failing index each iteration (where X is the total number of
 ///   allocations determined previously)
 ///
+/// Expects that `test_fn` has a deterministic number of memory allocations:
+/// - If an allocation was made to fail during a run of `test_fn`, but `test_fn`
+///   didn't return `error.OutOfMemory`, then `error.SwallowedOutOfMemoryError`
+///   is returned from `checkAllAllocationFailures`. You may want to ignore this
+///   depending on whether or not the code you're testing includes some strategies
+///   for recovering from `error.OutOfMemory`.
+/// - If a run of `test_fn` with an expected allocation failure executes without
+///   an allocation failure being induced, then `error.NondeterministicMemoryUsage`
+///   is returned. This error means that there are allocation points that won't be
+///   tested by the strategy this function employs (that is, there are sometimes more
+///   points of allocation than the initial run of `test_fn` detects).
+///
 /// ---
 ///
-/// Here's an example of using a simple test case that will cause a leak when the
+/// Here's an example using a simple test case that will cause a leak when the
 /// allocation of `bar` fails (but will pass normally):
 ///
 /// ```zig
@@ -645,12 +654,16 @@ pub fn checkAllAllocationFailures(backing_allocator: std.mem.Allocator, comptime
         args.@"0" = failing_allocator_inst.allocator();
 
         if (@call(.{}, test_fn, args)) |_| {
-            return error.NondeterministicMemoryUsage;
+            if (failing_allocator_inst.has_induced_failure) {
+                return error.SwallowedOutOfMemoryError;
+            } else {
+                return error.NondeterministicMemoryUsage;
+            }
         } else |err| switch (err) {
             error.OutOfMemory => {
                 if (failing_allocator_inst.allocated_bytes != failing_allocator_inst.freed_bytes) {
                     print(
-                        "\nfail_index: {d}/{d}\nallocated bytes: {d}\nfreed bytes: {d}\nallocations: {d}\ndeallocations: {d}\n",
+                        "\nfail_index: {d}/{d}\nallocated bytes: {d}\nfreed bytes: {d}\nallocations: {d}\ndeallocations: {d}\nallocation that was made to fail: {s}",
                         .{
                             fail_index,
                             needed_alloc_count,
@@ -658,6 +671,7 @@ pub fn checkAllAllocationFailures(backing_allocator: std.mem.Allocator, comptime
                             failing_allocator_inst.freed_bytes,
                             failing_allocator_inst.allocations,
                             failing_allocator_inst.deallocations,
+                            failing_allocator_inst.getStackTrace(),
                         },
                     );
                     return error.MemoryLeakDetected;