A 9P monkey drives random requests at a throwaway session and checks the documented rules

test/monkey9p.py starts pardes --detach with its own HOME, XDG dirs and
runtime dir, speaks raw 9P (test/ninep.py) with a timeout on every reply
and Tflush for held reads, and after each seeded operation checks that
pardes is alive, the one-failure rule over a marker-delimited log window
(with and without a follower), /index against /pane, and chunked against
whole reads. Every run writes a replayable ops log; a failure is saved
with its seed and step, shrunk by delta debugging over replays, and the
run goes on in a fresh session. Teardown makes the fuzzer a subreaper and
kills every process carrying the session's token.

zig build monkey-9p -- --seed N --steps M | --replay F | --shrink F;
a 150-step fixed-seed smoke run is part of fs-test.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 19 insertions, 1 deletions

diff --git a/build.zig b/build.zig
index 8646be05..e9e64056 100644
--- a/build.zig
+++ b/build.zig
@@ -1568,7 +1568,25 @@ pub fn build(b: *std.Build) void {
         if (enable_quic) run_fs_test.addArg("--quic");
         run_fs_test.setCwd(b.path("."));
         run_fs_test.has_side_effects = true;
-        b.step("fs-test", "exercise default 9P service and mounts with an independent client").dependOn(&run_fs_test.step);
+        const fs_test_step = b.step("fs-test", "exercise default 9P service and mounts with an independent client");
+        fs_test_step.dependOn(&run_fs_test.step);
+
+        // Random 9P operations against a throwaway detached session, checking
+        // the documented rules (test/monkey9p.py). The fixed-seed smoke run is
+        // part of fs-test; the long run is manual.
+        const run_monkey9p = b.addSystemCommand(&.{ "python3", "-B", "test/monkey9p.py" });
+        run_monkey9p.addArtifactArg(exe);
+        if (b.args) |args| run_monkey9p.addArgs(args);
+        run_monkey9p.setCwd(b.path("."));
+        run_monkey9p.has_side_effects = true;
+        b.step("monkey-9p", "random 9P operations checking the documented rules (-- [--seed N]... [--steps M] [--replay F] [--shrink F] [--no-shrink])").dependOn(&run_monkey9p.step);
+        const run_monkey9p_smoke = b.addSystemCommand(&.{ "python3", "-B", "test/monkey9p.py" });
+        run_monkey9p_smoke.addArtifactArg(exe);
+        run_monkey9p_smoke.addArg("--smoke");
+        run_monkey9p_smoke.setCwd(b.path("."));
+        run_monkey9p_smoke.has_side_effects = true;
+        b.step("monkey-9p-smoke", "a short fixed-seed 9P monkey run (part of fs-test)").dependOn(&run_monkey9p_smoke.step);
+        fs_test_step.dependOn(&run_monkey9p_smoke.step);
 
         const run_discovery = b.addSystemCommand(&.{ "python3", "-B", "test/fs.py" });
         run_discovery.addArtifactArg(exe);