node/test/parallel/test-stream-inheritance.js
Ruben Bridgewater e038d6a1cd
test: refactor common.expectsError
This completely refactors the `expectsError` behavior: so far it's
almost identical to `assert.throws(fn, object)` in case it was used
with a function as first argument. It had a magical property check
that allowed to verify a functions `type` in case `type` was passed
used in the validation object. This pattern is now completely removed
and `assert.throws()` should be used instead.

The main intent for `common.expectsError()` is to verify error cases
for callback based APIs. This is now more flexible by accepting all
validation possibilites that `assert.throws()` accepts as well. No
magical properties exist anymore. This reduces surprising behavior
for developers who are not used to the Node.js core code base.

This has the side effect that `common` is used significantly less
frequent.

PR-URL: https://github.com/nodejs/node/pull/31092
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
2019-12-31 15:54:20 +01:00

64 lines
1.9 KiB
JavaScript

'use strict';
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 CustomWritable,
`${this} does not inherit from CustomWritable`
);
assert.ok(
this instanceof Writable,
`${this} does not inherit from Writable`
);
}
Object.setPrototypeOf(CustomWritable, Writable);
Object.setPrototypeOf(CustomWritable.prototype, Writable.prototype);
new CustomWritable();
assert.throws(
CustomWritable,
{
code: 'ERR_ASSERTION',
constructor: assert.AssertionError,
message: 'undefined does not inherit from CustomWritable'
}
);
class OtherCustomWritable extends Writable {}
assert(!(new OtherCustomWritable() instanceof CustomWritable));
assert(!(new CustomWritable() instanceof OtherCustomWritable));