[Discussion/Request] Add a way to catch emitted events in gno test

[leohhhn]

Description

We should be able to test events that are being emitted in gno test. Is this feasible having in mind the multiple layers that events work on?

A suggested approach for the UX could be having a expectEmit function somewhere. I like Foundry's approach.

It does not really fit into std, which makes an even stronger case for moving TestSetXYZ functions out of the std package and adding them to a new gno-specific testing package (or similar), and having such a function there.

@thehowl what do you think?

[thehowl]

I still need to scope the whole idea out, but I'm thinking about having a simple helper function in testing to replace the ExecContext with one passed in by the user at runtime, which is executed within a closure.

gno/gnovm/stdlibs/testing/context.gno

Lines 9 to 21 in ef3b264

	type Context struct {
	IsOrigin bool
	CurrentRealm chain.Realm
	Deposit chain.Coins
	ChainID string
	Height uint64
	Time time.Time
	Banker chain.Banker
	Logger bool // TODO
	}
	func (c Context) Run(f func()) {
	}

This is still WIP, but my idea here is that the user can essentially add a "mock" emitter and capture all emitted events, within the closure passed to Run.