Setup basic jest environment

wasm/package.json

@@ -4,7 +4,7 @@
   "description": "ffmpeg.wasm core",
   "main": "dist/ffmpeg-core.js",
   "scripts": {
-    "test": "jest"
+    "test": "node --experimental-wasm-threads --experimental-wasm-bulk-memory ./node_modules/.bin/jest"
   },
   "repository": {
     "type": "git",

wasm/tests/bootstrap.test.js

+const {
+  initModule,
+  parseArgs,
+} = require('./utils');
+let Module = null;
+let ffmpeg = null;
+
+beforeAll(async () => {
+  Module = await initModule();
+  ffmpeg = Module.cwrap('proxy_main', 'number', ['number', 'number']);
+});
+
+test('test', () => {
+  const ret = ffmpeg(...parseArgs(['ffmpeg', '-v']));
+  expect(ret).toBe(0);
+});

wasm/tests/utils.js

+let Module = null;
+
+exports.initModule = () => (
+  new Promise((resolve) => {
+    const _Module = require('../dist/ffmpeg-core.js');
+    _Module.onRuntimeInitialized = () => {
+      Module = _Module;
+      resolve(Module);
+    }
+  })
+);
+
+exports.parseArgs = (args) => {
+  const argsPtr = Module._malloc(args.length * Uint32Array.BYTES_PER_ELEMENT);
+  args.forEach((s, idx) => {
+    const buf = Module._malloc(s.length + 1);
+    Module.writeAsciiToMemory(s, buf);
+    Module.setValue(argsPtr + (Uint32Array.BYTES_PER_ELEMENT * idx), buf, 'i32');
+  });
+  return [args.length, argsPtr];
+};