build.zig runners and testing improvements

1 files changed, 31 insertions, 1 deletions

diff --git a/test/e2e_harness.zig b/test/e2e_harness.zig
index 9099f13e..eb4c7a2f 100644
--- a/test/e2e_harness.zig
+++ b/test/e2e_harness.zig
@@ -15,7 +15,9 @@ extern "c" fn forkpty(
 extern "c" fn execvp(file: [*:0]const u8, argv: [*:null]const ?[*:0]const u8) c_int;
 extern "c" fn _exit(status: c_int) noreturn;
 
-fn nowMs() i64 {
+/// Monotonic milliseconds; the harness's only clock (std.time lost
+/// milliTimestamp in 0.16).
+pub fn nowMs() i64 {
     var ts: libc.timespec = undefined;
     _ = libc.clock_gettime(.MONOTONIC, &ts);
     return @as(i64, @intCast(ts.sec)) * 1000 + @divFloor(@as(i64, @intCast(ts.nsec)), 1_000_000);
@@ -133,6 +135,34 @@ pub const Harness = struct {
         if (self.trace) self.traceScreen("pump");
     }
 
+    /// Wait up to `ms` for the app to say something, feed whatever arrived to
+    /// the emulator, and report whether anything did. `ms` = 0 polls. This is
+    /// the event-driven half of `pump`: a caller that only cares about the
+    /// SETTLED grid sleeps in poll until the app actually writes, instead of
+    /// burning a fixed window per check (see snapshot.zig's waitStable).
+    pub fn pumpOnce(self: *Harness, ms: i64) !bool {
+        var fds = [_]posix.pollfd{.{ .fd = self.master, .events = posix.POLL.IN, .revents = 0 }};
+        const ready = posix.poll(&fds, @intCast(@max(0, ms))) catch 0;
+        if (ready == 0 or (fds[0].revents & posix.POLL.IN) == 0) return false;
+        var buf: [4096]u8 = undefined;
+        const n = posix.read(self.master, &buf) catch return false;
+        if (n == 0) return false;
+        self.raw.appendSlice(self.gpa, buf[0..n]) catch {};
+        self.stream.nextSlice(buf[0..n]);
+        return true;
+    }
+
+    /// Bytes sitting in the pty that nobody has picked up — keystrokes the app
+    /// has not read yet, or output we have not read yet (the master counts both
+    /// directions). Zero is the proof that the app has actually CONSUMED the
+    /// input just sent: without it, an app still asleep in its event loop looks
+    /// exactly like an app that has finished. See snapshot.zig's waitStable.
+    pub fn pending(self: *Harness) usize {
+        var n: c_int = 0;
+        if (posix.system.ioctl(self.master, posix.T.FIONREAD, @intFromPtr(&n)) != 0) return 0;
+        return if (n > 0) @intCast(n) else 0;
+    }
+
     /// Resize both the pty (SIGWINCH to the app) and our terminal (grid reflows
     /// to the new size). Harness terminal first so it's ready for the app's
     /// re-render at the new size.