Fix three stale tests that CI skips

They only run with prepared resources, so they went stale unseen. The armor stand test expects a fall on tick 1, where a summoned stand starts moving on tick 2; the two TNT tests set up the wrong scene.

Fixes #6235

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_018zuDTsnyHkP28bzn3u7S3m

crates/horizon-client/src/entities.rs

@@ -2322,6 +2322,12 @@ mod armor_stand_motion_tests {
         let start = Vec3::new(20.5, 20.0, 20.5);
         let mut stand = ArmorStand::new(1, start, 0.0);
         stand.on_ground = false;
+        // A summoned stand has no motion yet: the first tick only builds it
+        // (vanilla moves by the velocity, then applies gravity), so it falls
+        // from the second tick on (measured on the real server: drop 0, 0, 0.0784 blocks).
+        tick_stand(&mut stand, &world, &facts, &collision);
+        assert_eq!(stand.position, start);
+        assert!((stand.velocity.y + 0.0784).abs() < 1e-6);
         tick_stand(&mut stand, &world, &facts, &collision);
         assert_eq!(stand.previous, start);
         assert!(

crates/horizon-client/src/game/tnt.rs

@@ -624,7 +624,7 @@ mod tests {
         }
         world.set(20, 4, 20, water).unwrap();
         world.set(21, 4, 20, flowing).unwrap();
-        let at = Vec3::new(20.5, 6.0, 20.5);
+        let at = Vec3::new(20.5, 4.0, 20.5);
         let mut tnt = PrimedTnt {
             id: 0,
             position: at,
@@ -702,10 +702,15 @@ mod tests {
             .registry
             .default_state("minecraft:soul_sand")
             .unwrap();
-        let column = assets
+        // Soul sand makes an up-pushing column (`drag=false`); the block's
+        // default state is the down-dragging one.
+        let drag_down = assets
             .registry
             .default_state("minecraft:bubble_column")
             .unwrap();
+        let mut up = assets.registry.state(drag_down).unwrap().clone();
+        up.properties.insert("drag".into(), "false".into());
+        let column = assets.registry.resolve(&up).unwrap();
         for y in 3..=8 {
             world.set(20, y, 20, column).unwrap();
         }