1 files changed, 16 insertions, 5 deletions

diff --git a/src/detached/server.zig b/src/detached/server.zig
index 5c0e1487..212c9a3d 100644
--- a/src/detached/server.zig
+++ b/src/detached/server.zig
@@ -140,6 +140,8 @@ pub const Session = struct {
     worker_gpa: std.mem.Allocator,
     io: std.Io,
     core: *pardes.Pardes,
+    /// PARDES_TEST_CLOCK's virtual time (host_io.testClock).
+    test_clock: ?u64 = null,
     listener: c_int = -1,
     path_buf: [sun_path_len]u8 = undefined,
     path_len: usize = 0,
@@ -343,8 +345,14 @@ pub const Session = struct {
         return @ptrCast(@alignCast(ctx.?));
     }
 
+    fn clockNow(ctx: ?*anyopaque) u64 {
+        const s = of(ctx);
+        return s.test_clock orelse host_io.monotonicNs();
+    }
+
     const vtable: host_io.Host.VTable = .{
         .wait_input = waitInput,
+        .now = clockNow,
         .present = present,
         .poll_frame = pollFrame,
         .spawn = spawn,
@@ -827,8 +835,9 @@ pub const Session = struct {
             pardes.turn.rest();
             nap(if (timeout_ms == 0) 16 else timeout_ms);
             pardes.turn.wake();
-            // An animating frame's wait is the frame: tick it.
-            if (timeout_ms != 0) s.core.update(.tick);
+            if (timeout_ms != 0) if (s.test_clock) |*virtual| {
+                virtual.* = @max(virtual.*, s.core.nextWake() orelse virtual.*);
+            };
             return;
         }
         var timeout: c_int = if (timeout_ms == 0) -1 else @intCast(@min(timeout_ms, std.math.maxInt(c_int)));
@@ -838,9 +847,10 @@ pub const Session = struct {
         const ready = libc.poll(&fds, @intCast(n), timeout);
         pardes.turn.wake();
         if (ready > 0) s.dispatch(fds[0..n], src[0..n]);
-        // Animating, the frame's time is up: advance it. There is no other
-        // tick in a detached session, and without it an animation never ends.
-        if (timeout_ms != 0 and monotonicMs() -| now >= timeout_ms) s.core.update(.tick);
+        // The core's wake ran out; the pump advances it from `now`.
+        if (timeout_ms != 0 and monotonicMs() -| now >= timeout_ms) if (s.test_clock) |*virtual| {
+            virtual.* = @max(virtual.*, s.core.nextWake() orelse virtual.*);
+        };
         _ = s.drainCompletions(true);
         s.expire(monotonicMs());
         s.harvest();
@@ -1155,6 +1165,7 @@ pub fn run(init: std.process.Init, opts: pardes.Options, name: []const u8) !void
         .cols = options.cols,
         .rows = options.rows,
         .prompt_rcs = host_io.Shell.prepare(),
+        .test_clock = host_io.testClock(),
     };
     defer session.core.deinit();
     defer session.deinit();