1function assert_ArrayBuffer(actual, { size=0, shared=false, detached=false }, message) {
2  // https://github.com/WebAssembly/spec/issues/840
3  // See https://github.com/whatwg/html/issues/5380 for why not `self.SharedArrayBuffer`
4  const isShared = !("isView" in actual.constructor);
5  assert_equals(isShared, shared, `${message}: constructor`);
6  const sharedString = shared ? "Shared" : "";
7  assert_equals(actual.toString(), `[object ${sharedString}ArrayBuffer]`, `${message}: toString()`);
8  assert_equals(Object.getPrototypeOf(actual).toString(), `[object ${sharedString}ArrayBuffer]`, `${message}: prototype toString()`);
9  if (detached) {
10    // https://github.com/tc39/ecma262/issues/678
11    let byteLength;
12    try {
13      byteLength = actual.byteLength;
14    } catch (e) {
15      byteLength = 0;
16    }
17    assert_equals(byteLength, 0, `${message}: detached size`);
18  } else {
19    assert_equals(actual.byteLength, 0x10000 * size, `${message}: size`);
20    if (size > 0) {
21      const array = new Uint8Array(actual);
22      assert_equals(array[0], 0, `${message}: first element`);
23      assert_equals(array[array.byteLength - 1], 0, `${message}: last element`);
24    }
25  }
26  assert_equals(Object.isFrozen(actual), shared, "buffer frozen");
27  assert_equals(Object.isExtensible(actual), !shared, "buffer extensibility");
28}
29
30function assert_Memory(memory, { size=0, shared=false }) {
31  assert_equals(Object.getPrototypeOf(memory), WebAssembly.Memory.prototype,
32                "prototype");
33  assert_true(Object.isExtensible(memory), "extensible");
34
35  // https://github.com/WebAssembly/spec/issues/840
36  assert_equals(memory.buffer, memory.buffer, "buffer should be idempotent");
37  assert_ArrayBuffer(memory.buffer, { size, shared });
38}
39