Add a mock Stargate querier

[larry0x]

Currently MockQuerier throws an error when a user attempts to do a Stargate query:

cosmwasm/packages/std/src/testing/mock.rs

Lines 537 to 539 in 4565841

	QueryRequest::Stargate { .. } => SystemResult::Err(SystemError::UnsupportedRequest {
	kind: "Stargate".to_string(),
	}),

It may be helpful to let user define a handler function for Stargate queries, similar to the case for the custom query, and if the user does not define such a handler, throw an error like it does now.

[0xfirefist]

I also am looking into a solution for mocking stargate queries and came to the same conclusion.

Is there any way to do so if not this?

[larry0x]

I also am looking into a solution for mocking stargate queries and came to the same conclusion.

Is there any way to do so if not this?

I'm going to make a fork of cosmwasm-std for now

[webmaster128]

A solution for this should be straight forward and not break anything. Feel free to submit a PR.

Given how limited the usability of Stargate queries is in practive right now (chains need to enable each query one by one), this is currently not a priority for Confio to work on.

[chipshort]

We should do this for gRPC queries by adding a field to the MockQuerier.