(assertions): add `hasParameters()` and `findParameters()` API

There should be a way to access the Parameters of the template natively with the assertions library.

Use Case

https://github.com/aws/aws-cdk/blob/7fbf092c613f5618575b9b1a10b9e06fa36abad3/packages/%40aws-cdk/aws-autoscaling/test/scheduled-action.test.ts#L61

There are quite a few lines of code in the above example so I did not quote it all. But the idea is that if you want to assert on any parameters along with the properties, you can only use Template.fromStack(stack).templateMatches() which then requires you to provide the entire template. This is excess code if the user does not need to assert that the entire template is a 1-1 match.

Proposed Solution

APIs similar to what is available for hasMapping(), hasResource(), and hasOutput(). Should also have findParameters() as well.

Other

Workaround is:

expect(Template.fromStack(stack).toJSON().Parameters).toEqual({});

[ ] :wave: I may be able to implement this feature request
[ ] :warning: This feature might incur a breaking change

This is a :rocket: Feature Request

aws / aws-cdk