Grab System Test

Run 6 test suites covering distance grab, one-hand grab, two-hand grab, system/component registration, hand pinch grab, and stability.

Configuration:

• EXAMPLE_DIR: $IWSDK_REPO_ROOT/examples/grab

Tool calls: every tool call is npx @iwsdk/cli <subcommand> [--input-json '<JSON>'] [--timeout <ms>], run from inside the example workspace (cwd $EXAMPLE_DIR). The CLI auto-discovers the IWSDK app root from cwd, so no path tricks are required. Run npx @iwsdk/cli mcp inspect from the example to discover available tools and their CLI subcommands.

• <JSON> is a JSON object string. Omit --input-json if no arguments are needed.
• Output is JSON on stdout: {ok, workspaceRoot, operation, result}. Parse it to check assertions.
• Use --timeout 20000 for operations that may take longer (reload, xr enter, xr animate-to, screenshot).

IMPORTANT: Run each Bash command one at a time. Parse the JSON output and verify assertions before moving to the next command. Do NOT chain multiple CLI commands together.

IMPORTANT: When the instructions say "wait N seconds", use sleep N as a separate Bash command.

Step 1: Install Dependencies

cd $IWSDK_REPO_ROOT/examples/grab && npm run fresh:install

Wait for this to complete before proceeding.

Step 2: Start Dev Server

Start the dev server as a background task using the Bash tool's run_in_background: true parameter:

cd $IWSDK_REPO_ROOT/examples/grab && npm run dev

IMPORTANT: This command MUST be run with run_in_background: true on the Bash tool — do NOT append & to the command itself.

Once the background task is launched, poll the output for Vite's ready message (up to 60s). You can also run npx @iwsdk/cli dev status from the example directory until state.running becomes true. You do not need to extract or manage the port yourself; subsequent commands resolve the active runtime through the CLI automatically.

If the server fails to start within 60 seconds, report FAIL for all suites and skip to Step 5.

Step 3: Verify Connectivity

npx @iwsdk/cli ecs systems 2>/dev/null

This must return JSON with a list of systems. If it fails:

1. Check the dev server output for errors
2. Try killing and restarting the server (Step 2)
3. If it still fails, report FAIL for all suites and skip to Step 5

Step 4: Run Test Suites

Pre-test Setup

Run these commands in order:

1. npx @iwsdk/cli browser reload --timeout 20000 2>/dev/null Then: sleep 3
2. npx @iwsdk/cli xr enter --timeout 20000 2>/dev/null Then: sleep 2
3. npx @iwsdk/cli browser logs --input-json '{"count":20,"level":["error","warn"]}' 2>/dev/null Assert: No error-level logs.

Entity Discovery

Discover all grab entities dynamically:

npx @iwsdk/cli ecs find --input-json '{"withComponents":["DistanceGrabbable"]}' 2>/dev/null

Assert: At least 1 entity. In the runtime hierarchy below, select the entity whose sceneNodeId is pyramid-distance-grab (the Distance Grabbable Pyramid) and save its entity index as <distance>. This example's Earth is also distance-grabbable, but it uses RotateAtSource and therefore is not valid for the positional MoveTowardsTarget assertion in Test 1.3.

npx @iwsdk/cli ecs find --input-json '{"withComponents":["OneHandGrabbable"]}' 2>/dev/null

Assert: At least 1 entity. Save first as <onehand>.

npx @iwsdk/cli ecs find --input-json '{"withComponents":["TwoHandsGrabbable"]}' 2>/dev/null

Assert: At least 1 entity. Save first as <twohand>.

Get entity positions via scene hierarchy:

npx @iwsdk/cli scene runtime-hierarchy --input-json '{"maxDepth":3}' 2>/dev/null

Find Object3D UUIDs for each grab entity, then query their transforms:

npx @iwsdk/cli scene transform --input-json '{"uuid":"<entity-uuid>"}' 2>/dev/null

Save positionRelativeToXROrigin as <distance-pos>, <onehand-pos>, <twohand-pos>.

Verify GrabSystem is active:

npx @iwsdk/cli ecs systems 2>/dev/null

Assert: GrabSystem at priority -3.

Component Reference

Critical Distinction: Distance grab uses trigger (npx @iwsdk/cli xr set-select-value). One-hand and two-hand grab use squeeze (npx @iwsdk/cli xr set-gamepad-state button index 1). Wrong button silently fails.

Suite 1: Distance Grab (Ray + Trigger)

Test 1.1: Ray Hover

npx @iwsdk/cli xr look-at --input-json '{"device":"controller-right","target":{"x":<distance-pos.x>,"y":<distance-pos.y>,"z":<distance-pos.z>},"moveToDistance":0.8}' 2>/dev/null

Then: sleep 1

npx @iwsdk/cli ecs query --input-json '{"entityIndex":<distance>,"components":["Hovered"]}' 2>/dev/null

Assert: Hovered present.

Test 1.2: Trigger to Grab

npx @iwsdk/cli ecs snapshot --input-json '{"label":"before-grab"}' 2>/dev/null

npx @iwsdk/cli xr set-select-value --input-json '{"device":"controller-right","value":1}' 2>/dev/null

Then: sleep 0.5

npx @iwsdk/cli ecs query --input-json '{"entityIndex":<distance>,"components":["Hovered","Pressed"]}' 2>/dev/null

Assert: Both Hovered and Pressed present.

Test 1.3: Move While Grabbed

npx @iwsdk/cli xr animate-to --input-json '{"device":"controller-right","position":{"x":0.5,"y":1.5,"z":-1.0},"duration":1.0}' --timeout 20000 2>/dev/null

Then: sleep 1.5

npx @iwsdk/cli ecs snapshot --input-json '{"label":"after-move"}' 2>/dev/null

npx @iwsdk/cli ecs diff --input-json '{"from":"before-grab","to":"after-move"}' 2>/dev/null

Assert: Entity's Transform.position must differ from initial.

Test 1.4: Release Trigger

npx @iwsdk/cli xr set-select-value --input-json '{"device":"controller-right","value":0}' 2>/dev/null

Then: sleep 0.5

npx @iwsdk/cli ecs query --input-json '{"entityIndex":<distance>,"components":["Hovered","Pressed"]}' 2>/dev/null

Assert: Pressed removed. Handle persists (it's permanent).

Test 1.5: Point Away — Clean State

npx @iwsdk/cli xr look-at --input-json '{"device":"controller-right","target":{"x":0,"y":1.6,"z":-5}}' 2>/dev/null

Then: sleep 1

npx @iwsdk/cli ecs query --input-json '{"entityIndex":<distance>,"components":["Hovered"]}' 2>/dev/null

Assert: Hovered removed.

Suite 2: One-Hand Grab (Squeeze)

Test 2.1: Ray Isolation — Ray Cannot Interact

npx @iwsdk/cli xr look-at --input-json '{"device":"controller-right","target":{"x":<onehand-pos.x>,"y":<onehand-pos.y>,"z":<onehand-pos.z>},"moveToDistance":0.5}' 2>/dev/null

Then: sleep 1

npx @iwsdk/cli ecs query --input-json '{"entityIndex":<onehand>,"components":["Hovered","Pressed"]}' 2>/dev/null

Assert: No Hovered or Pressed on entity (ray is denied by pointerEventsType).

Test 2.2: Position Controller at Object + Squeeze

npx @iwsdk/cli xr set-transform --input-json '{"device":"controller-right","position":{"x":<onehand-pos.x>,"y":<onehand-pos.y>,"z":<onehand-pos.z>},"orientation":{"pitch":0,"roll":0,"yaw":0}}' 2>/dev/null

npx @iwsdk/cli xr set-gamepad-state --input-json '{"device":"controller-right","buttons":[{"index":1,"value":1,"touched":true}]}' 2>/dev/null

Then: sleep 0.5

npx @iwsdk/cli ecs snapshot --input-json '{"label":"before-onehand"}' 2>/dev/null

Test 2.3: Move While Squeezing

npx @iwsdk/cli xr animate-to --input-json '{"device":"controller-right","position":{"x":<onehand-pos.x>,"y":<onehand-pos.y + 0.3>,"z":<onehand-pos.z + 0.3>},"duration":1.0}' --timeout 20000 2>/dev/null

Then: sleep 1.5

npx @iwsdk/cli ecs snapshot --input-json '{"label":"after-onehand-move"}' 2>/dev/null

npx @iwsdk/cli ecs diff --input-json '{"from":"before-onehand","to":"after-onehand-move"}' 2>/dev/null

Assert: Entity's Transform.position must have changed to follow the controller.

Test 2.4: Release Squeeze

npx @iwsdk/cli xr set-gamepad-state --input-json '{"device":"controller-right","buttons":[{"index":1,"value":0,"touched":false}]}' 2>/dev/null

Assert: Entity stops moving (Transform remains at released position).

Suite 3: Two-Hand Grab (Both Controllers Squeeze)

Test 3.1: Position Both Controllers Near Object

npx @iwsdk/cli xr set-transform --input-json '{"device":"controller-left","position":{"x":<twohand-pos.x - 0.15>,"y":<twohand-pos.y>,"z":<twohand-pos.z>},"orientation":{"pitch":0,"roll":0,"yaw":0}}' 2>/dev/null

npx @iwsdk/cli xr set-transform --input-json '{"device":"controller-right","position":{"x":<twohand-pos.x + 0.15>,"y":<twohand-pos.y>,"z":<twohand-pos.z>},"orientation":{"pitch":0,"roll":0,"yaw":0}}' 2>/dev/null

Test 3.2: Both Squeeze + Snapshot

npx @iwsdk/cli ecs snapshot --input-json '{"label":"before-twohand"}' 2>/dev/null

npx @iwsdk/cli xr set-gamepad-state --input-json '{"device":"controller-left","buttons":[{"index":1,"value":1,"touched":true}]}' 2>/dev/null

npx @iwsdk/cli xr set-gamepad-state --input-json '{"device":"controller-right","buttons":[{"index":1,"value":1,"touched":true}]}' 2>/dev/null

Then: sleep 0.5

Test 3.3: Spread Hands — Scale Up

npx @iwsdk/cli xr animate-to --input-json '{"device":"controller-left","position":{"x":<twohand-pos.x - 0.5>,"y":<twohand-pos.y>,"z":<twohand-pos.z>},"duration":1.0}' --timeout 20000 2>/dev/null

npx @iwsdk/cli xr animate-to --input-json '{"device":"controller-right","position":{"x":<twohand-pos.x + 0.5>,"y":<twohand-pos.y>,"z":<twohand-pos.z>},"duration":1.0}' --timeout 20000 2>/dev/null

Then: sleep 1.5

npx @iwsdk/cli ecs snapshot --input-json '{"label":"after-twohand-scale"}' 2>/dev/null

npx @iwsdk/cli ecs diff --input-json '{"from":"before-twohand","to":"after-twohand-scale"}' 2>/dev/null

Assert: Entity Transform.scale should be larger than initial.

Test 3.4: Release Both

npx @iwsdk/cli xr set-gamepad-state --input-json '{"device":"controller-left","buttons":[{"index":1,"value":0,"touched":false}]}' 2>/dev/null

npx @iwsdk/cli xr set-gamepad-state --input-json '{"device":"controller-right","buttons":[{"index":1,"value":0,"touched":false}]}' 2>/dev/null

Suite 4: System & Component Registration

Test 4.1: GrabSystem at Correct Priority

npx @iwsdk/cli ecs systems 2>/dev/null

Assert: GrabSystem present at priority -3.

Test 4.2: Components Registered

npx @iwsdk/cli ecs components 2>/dev/null

Assert: Must include: OneHandGrabbable, TwoHandsGrabbable, DistanceGrabbable, Handle.

Suite 5: Hand Pinch Grab (run_sequence)

The grab example sets useHandPinchForGrab, so an emulated hand's pinch grabs OneHandGrabbable entities. IWSDK resolves the target names the hand sequences use.

Test 5.1: Hand Input and Targets

npx @iwsdk/cli xr set-input-mode --input-json '{"mode":"hand"}' 2>/dev/null

npx @iwsdk/cli xr list-targets 2>/dev/null

Assert: resolver is true and targets includes Map Pin 1, Map Pin 2, and Map Pin 3. Save the Map Pin 1 entry's position (box centre) as <pin-pos> and size as <pin-size>, and find its entity index with npx @iwsdk/cli ecs find --input-json '{"namePattern":"^Map Pin 1$"}' as <pin>.

Test 5.2: Pinch-Grab and Carry

The carry position is where the pin's base goes while it is held (here 30 cm toward the user and 10 cm up):

npx @iwsdk/cli xr run-sequence --input-json '{"device":"hand-right","steps":[{"label":"grab","target":"Map Pin 1","approach":{"distance":0.06},"pinch":{"value":1,"at":"arrival"}},{"label":"carry","position":{"x":<pin-pos.x - 0.05>,"y":<pin-pos.y - pin-size.y/2 + 0.1>,"z":<pin-pos.z + 0.3>},"depart":{"distance":0.08}}]}' --timeout 45000 2>/dev/null

Assert: completed is true and events contains selectstart.

npx @iwsdk/cli ecs query --input-json '{"entityIndex":<pin>,"components":["Grabbed"]}' 2>/dev/null

Assert: Grabbed present. Query Map Pin 2 and Map Pin 3 the same way and assert Grabbed is absent on both.

Test 5.3: Release

npx @iwsdk/cli xr run-sequence --input-json '{"device":"hand-right","steps":[{"label":"release","pinch":0,"duration":0.15}]}' --timeout 45000 2>/dev/null

Assert: events contains selectend. Then sleep 0.5, query <pin> for ["Grabbed"] and assert it is absent. Run npx @iwsdk/cli xr list-targets again: the Map Pin 1 centre must have moved at least 0.2 m from <pin-pos>, and its base (centre y minus half its height) must be within 0.02 m of the carry position.

Test 5.4: Back to Controllers

npx @iwsdk/cli xr set-input-mode --input-json '{"mode":"controller"}' 2>/dev/null

Suite 6: Stability

npx @iwsdk/cli browser logs --input-json '{"count":30,"level":["error","warn"]}' 2>/dev/null

Assert: No application-level errors or warnings. Pre-existing 404 resource errors from page load are acceptable.

Step 5: Cleanup & Results

Kill the dev server:

cd $IWSDK_REPO_ROOT/examples/grab && npx @iwsdk/cli dev down

Output a summary table:

| Suite                         | Result    |
|-------------------------------|-----------|
| 1. Distance Grab              | PASS/FAIL |
| 2. One-Hand Grab              | PASS/FAIL |
| 3. Two-Hand Grab              | PASS/FAIL |
| 4. System/Component Reg.      | PASS/FAIL |
| 5. Hand Pinch Grab            | PASS/FAIL |
| 6. Stability                  | PASS/FAIL |

If any suite fails, include which assertion failed and actual vs expected values.

Recovery

If at any point a transient error occurs (server crash, WebSocket timeout, connection refused, etc.) that is NOT caused by a source code bug:

1. Stop the dev server: cd $IWSDK_REPO_ROOT/examples/grab && npx @iwsdk/cli dev down
2. Restart: re-run Step 2 to start a fresh dev server
3. Re-run the Pre-test Setup (reload, accept session)
4. Retry the failed suite

Only give up after one retry attempt per suite. If the same suite fails twice, mark it FAIL and continue to the next suite.

Known Issues & Workarounds

No Hovered/Pressed for near-field grabs

OneHandGrabbable and TwoHandsGrabbable entities do NOT get Hovered or Pressed tags. Only distance grab (via ray) gets these tags. Use npx @iwsdk/cli ecs snapshot/npx @iwsdk/cli ecs diff to verify near-field grabs.

Handle component is permanent

Handle is added by GrabSystem at init time and never removed. Grab state is tracked inside Handle.instance.outputState.

Trigger vs Squeeze confusion

Distance grab uses trigger (set_select_value), not squeeze. One-hand and two-hand grab use squeeze (set_gamepad_state button index 1). Wrong button silently fails.

Hand sequences need a longer timeout

xr run-sequence resolves when the whole interaction is done, up to 28 s after it is sent. Pass --timeout 45000.

Grab sphere radius is 0.07m

The grab sphere intersector has a default radius of 7cm. Position the controller at the object's center for reliable detection.

Entity indices change on reload

Never cache entity indices across page reloads. Always re-discover via npx @iwsdk/cli ecs find.