Some files already were using `noop` in place of `() => {}`.
It's both clearer what it means and is easier to type.
This updates all test files to fully use `noop`, and
adds a shared import from the test lib file.
This commit introduces a seperate `page_params` file for billing module
since we only use certain page_params in billing module only that it does
not make sense to include them in the main `page_params.ts`.
Also introduced `zpage_billing_params` for proper testing new `page_params`
in billing module.
This lets us simplify the long-ish ‘../../static/js’ paths, and will
remove the need for the ‘zrequire’ wrapper.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Anders Kaseorg
Evy Kassirer
Lalit