This patch adds a new require, `puppeteer/Errors`, that
holds all the Puppeteer-specific error classes.
Currently, the only custom error class we use is `TimeoutError`. We'll
expand in future with `CrashError` and some others.
Fixes#1694.
Since Node 10, `console.assert` no longer throws an AssertionError.
(This is generally good since it aligns Node.js with Browsers.)
This patch migrates all usages of `console.assert` in our codebase.
- All the `lib/` and testing code is migrated onto a handmade `assert`
function. This is to make Puppeteer transpilation / bundling easier.
- All the tooling is switched to use Node's `assert` module.
Fixes#2547.
This patch introduces a tiny test runner to run puppeteer tests.
The test runner is self-container and allows parallel (wrt IO) test execution.
It will also allow us to split tests into multiple files if necessary.
Comparing to the jasmine, the testrunner supports parallel execution, properly
handles "unhandled promise rejection" event and signals.
Comparing to ava/jest, the testrunner doesn't run multiple node processes,
which makes it simpler but sufficient for our goals.
