Test Grab

Grab System Test

Run 5 test suites covering distance grab, one-hand grab, two-hand grab, system/component registration, and stability.

Configuration:

• EXAMPLE_DIR: $IWSDK_REPO_ROOT/examples/grab

Tool calls: every tool call is npx iwsdk <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 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 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 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 browser reload --timeout 20000 2>/dev/null Then: sleep 3

2. npx iwsdk xr enter --timeout 20000 2>/dev/null Then: sleep 2

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

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

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

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

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

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

npx iwsdk 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 ecs systems 2>/dev/null

Assert: GrabSystem at priority -3.

Component Reference

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

Suite 1: Distance Grab (Ray + Trigger)

Test 1.1: Ray Hover

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

Assert: Hovered present.

Test 1.2: Trigger to Grab

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

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

Then: sleep 0.5

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

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

Then: sleep 0.5

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

Then: sleep 1

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

Test 2.3: Move While Squeezing

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

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

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

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

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

npx iwsdk 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 ecs systems 2>/dev/null

Assert: GrabSystem present at priority -3.

Test 4.2: Components Registered

npx iwsdk ecs components 2>/dev/null

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

Suite 5: Stability

npx iwsdk 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 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. 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 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 ecs snapshot/npx iwsdk 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.

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 ecs find.