These helpers are often imported by various tests throughout the
repository, but the helpers aren't exported/exposed from the public
entry-point; even though they confusingly reside in there.
This commit fixes this, and moves the helpers into
`packages/private/testing`. This is a preparation for the `ts_project`
migration where we don't want to leverage deep imports between packages.
PR Close#61476
A lot of our tests are wrapped in `{}` which serves no purpose, aside from increasing the nesting level and, in some cases, causing confusion. The braces appear to be a leftover from a time when all tests were wrapped in a `function main() {}`. The function declaration was removed in #21053, but the braces remained, presumably because it was easier to search&replace for `function main()`, but not to remove the braces at the same time.
PR Close#52239
This commit updates the pipes presents in the `CommonModule` and annotates them with the `standalone: true` flag. With that flag, the pipes can now be imported individually, as well as imported via the `CommonModule`.
PR Close#46401