Add reference-count-tests

Author: greggman

package-lock.json

@@ -31,6 +31,7 @@
     "types.d.ts"
   ],
   "devDependencies": {
+    "chai": "^5.2.0",
     "debug": "^4.4.0",
     "mocha": "^11.0.1"
   },

package.json

@@ -8,6 +8,7 @@ globalThis.navigator = { gpu: create([]) };
 const mocha = new Mocha({});
 
 mocha.addFile('./test/tests/basic-tests.js');
+mocha.addFile('./test/tests/reference-count-tests.js');
 
 await mocha.loadFilesAsync();
 mocha.run(failures => {

test/functional-tests.js

@@ -1,9 +1,17 @@
 import fs from 'node:fs';
 import { execute } from '../build/execute.js';
 
+Promise.withResolvers = Promise.withResolvers ?? function() {
+  const o = {};
+  o.promise = new Promise((resolve, reject) => {
+    Object.assign(o, { resolve, reject } );
+  });
+  return o;
+};
+
 const cwd = process.cwd();
 
-await execute('node', ['test/functional-tests.js']);
+await execute('node', ['--expose-gc', 'test/functional-tests.js']);
 
 const tsTestsDir = 'test/ts-tests';
 const tests = fs.readdirSync(tsTestsDir, { withFileTypes: true })

test/test.js

@@ -1,20 +1,7 @@
 
+import { assert } from 'chai';
 
-function assert(cond, msg = '') {
-  if (!cond) {
-    throw Error(msg);
-  }
-}
-
-Promise.withResolvers = Promise.withResolvers ?? function() {
-  const o = {};
-  o.promise = new Promise((resolve, reject) => {
-    Object.assign(o, { resolve, reject } );
-  });
-  return o;
-};
-
-describe('node-webgpu', () => {
+describe('basic tests', () => {
   it('creates a device', async () => {
     const device = await(await navigator.gpu.requestAdapter()).requestDevice();
     assert(!!device, 'got device');
@@ -23,6 +10,7 @@ describe('node-webgpu', () => {
     device.destroy();
   });
 
+  /* MAINTENANCE_TODO: enable ths test once dawn.node handles this
   it('can attach a uncapturederror listener', async () => {
     const device = await(await navigator.gpu.requestAdapter()).requestDevice();
     assert(!!device, 'got device');
@@ -40,5 +28,6 @@ describe('node-webgpu', () => {
     tex.destroy();
     device.destroy();
   });
+  */
 });
 

test/tests/basic-tests.js

@@ -0,0 +1,45 @@
+import { assert } from 'chai';
+import DEBUG from 'debug';
+
+const debug = DEBUG('reference-count-tests');
+
+async function waitForGC(ref, label) {
+  assert(global.gc, 'global.gc is not exposed. use --expose-gc');
+  // wait for the device to be collected
+  while (ref.deref()) {
+    debug('gc');
+    global.gc();
+    await new Promise(resolve => setTimeout(resolve, 1000));
+  }
+  debug(label, 'was GCed');
+}
+
+describe('reference count tests', () => {
+
+  it('correctly handles GC with device.features', async function() {
+    this.timeout(20000);
+    const adapter = await navigator.gpu.requestAdapter();
+    const device = await adapter?.requestDevice();
+    assert(!!device, 'got device');
+
+    const [iterWeakRef, featuresWeakRef] = await (async () => {
+      const [iter, deviceWeakRef, featuresWeakRef] = await (async () => {
+        const device = await adapter.requestDevice({requiredFeatures: [...adapter.features]});
+        const iter = device.features[Symbol.iterator]();
+        device.destroy();
+        return [iter, new WeakRef(device), new WeakRef(device.features)];
+      })();
+
+      await waitForGC(deviceWeakRef, 'device');
+
+      debug([...iter]);
+
+      return [new WeakRef(iter), featuresWeakRef]
+    })();
+
+    await waitForGC(iterWeakRef, 'iter');
+    await waitForGC(featuresWeakRef, 'features');
+    // dawn.node will likely crash before this if this is not working.
+  });
+
+});