node/test/parallel/test-stream-inheritance.js
James M Snell e48d58b8b2 assert: fix AssertionError, assign error code
Using `assert.AssertionError()` without the `new` keyword results
in a non-intuitive error:

```js
> assert.AssertionError({})
TypeError: Cannot assign to read only property 'name' of function 'function ok(value, message) {
  if (!value) fail(value, true, message, '==', assert.ok);
}'
    at Function.AssertionError (assert.js:45:13)
    at repl:1:8
    at realRunInThisContextScript (vm.js:22:35)
    at sigintHandlersWrap (vm.js:98:12)
    at ContextifyScript.Script.runInThisContext (vm.js:24:12)
    at REPLServer.defaultEval (repl.js:346:29)
    at bound (domain.js:280:14)
    at REPLServer.runBound [as eval] (domain.js:293:12)
    at REPLServer.onLine (repl.js:545:10)
    at emitOne (events.js:101:20)
>
```

The `assert.AssertionError()` can only be used correctly with `new`,
so this converts it into a proper ES6 class that will give an
appropriate error message.

This also associates the appropriate internal/errors code with all
`assert.AssertionError` instances and updates the appropriate test
cases.

PR-URL: https://github.com/nodejs/node/pull/12651
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
2017-05-04 07:18:17 -07:00

50 lines
1.6 KiB
JavaScript

'use strict';
const common = require('../common');
const assert = require('assert');
const { Readable, Writable, Duplex, Transform } = require('stream');
const readable = new Readable({ read() {} });
const writable = new Writable({ write() {} });
const duplex = new Duplex({ read() {}, write() {} });
const transform = new Transform({ transform() {} });
assert.ok(readable instanceof Readable);
assert.ok(!(writable instanceof Readable));
assert.ok(duplex instanceof Readable);
assert.ok(transform instanceof Readable);
assert.ok(!(readable instanceof Writable));
assert.ok(writable instanceof Writable);
assert.ok(duplex instanceof Writable);
assert.ok(transform instanceof Writable);
assert.ok(!(readable instanceof Duplex));
assert.ok(!(writable instanceof Duplex));
assert.ok(duplex instanceof Duplex);
assert.ok(transform instanceof Duplex);
assert.ok(!(readable instanceof Transform));
assert.ok(!(writable instanceof Transform));
assert.ok(!(duplex instanceof Transform));
assert.ok(transform instanceof Transform);
assert.ok(!(null instanceof Writable));
assert.ok(!(undefined instanceof Writable));
// Simple inheritance check for `Writable` works fine in a subclass constructor.
function CustomWritable() {
assert.ok(this instanceof Writable, 'inherits from Writable');
assert.ok(this instanceof CustomWritable, 'inherits from CustomWritable');
}
Object.setPrototypeOf(CustomWritable, Writable);
Object.setPrototypeOf(CustomWritable.prototype, Writable.prototype);
new CustomWritable();
assert.throws(CustomWritable,
common.expectsError({
code: 'ERR_ASSERTION',
message: /^inherits from Writable$/
}));