diff --git a/test/world.zig b/test/world.zig
index 3045211..4e09d6d 100644
--- a/test/world.zig
+++ b/test/world.zig
@@ -65,3 +65,39 @@ test "World_progress_w_0" {
     try expect(p.x != 0);
     try expect(p.y != 0);
 }
+
+test "World_progress_w_t" {
+    var world = try World.init(std.testing.allocator);
+    defer world.deinit();
+
+    _ = world.component(Position);
+    _ = world.component(Velocity);
+
+    const e1 = world.entity(.{}, .{ Position, Velocity });
+
+    const move_system = world.system("move", move, c.EcsOnUpdate, "Position, Velocity");
+
+    var ctx = util.Probe.init();
+    c.ecs_set_context(world.raw, &ctx);
+
+    _ = e1.set(Position, .{ .x = 0, .y = 0 });
+    _ = e1.set(Velocity, .{ .x = 1, .y = 2 });
+
+    _ = world.progress(2);
+
+    try expectEql(ctx.count, 1);
+    try expectEql(ctx.invoked, 1);
+    try expectEql(ctx.system, move_system.raw);
+    try expectEql(ctx.termCount, 2);
+    try expectEql(ctx.param, null);
+
+    try expectEql(ctx.e[0], e1.raw);
+    try expectEql(ctx.c[0][0], (try world.lookupByType(Position)).raw);
+    try expectEql(ctx.c[0][1], (try world.lookupByType(Velocity)).raw);
+    try expectEql(ctx.s[0][0], 0);
+    try expectEql(ctx.s[0][1], 0);
+
+    const p = e1.get(Position).?;
+    try expect(p.x == 2);
+    try expect(p.y == 4);
+}