First Composed Response
As it stands, your execute function only returns a Response::default(). That is the bare minimum. Eventually, as your smart contract communicates with others or even other modules, it needs to pass more information as part of its response. This section is a step in this direction.
If you skipped the previous section, you can just switch the project to its first-multi-test branch and take it from there.
Add an event
A very simple thing to add to your response is an event. It is the same concept as events in Cosmos. You can add attributes to the wasm event that is added by the CosmWasm module itself, and is always present.
Better yet, you add your own event, which will mean something to those who interact with your smart contract. Update your src/contract.rs with:
...
use cosmwasm_std::{
- entry_point, to_json_binary, Binary, Deps, DepsMut, Env, MessageInfo, Response, StdResult,
+ entry_point, to_json_binary, Binary, Deps, DepsMut, Env, Event, MessageInfo, Response,
+ StdResult,
};
...
fn execute_register(deps: DepsMut, info: MessageInfo, name: String) -> ContractResult {
let key = name.as_bytes();
- let record = NameRecord { owner: info.sender };
+ let record = NameRecord {
+ owner: info.sender.to_owned(),
+ };
...
- Ok(Response::default())
+ let registration_event = Event::new("name-register")
+ .add_attribute("name", name)
+ .add_attribute("owner", info.sender);
+ let resp = Response::default().add_event(registration_event);
+ Ok(resp)
}
...Note that:
- You are free to choose any event name other than
name-register. You ought to make it a visible constant too. - The CosmWasm module will prefix it with
wasm-before sending the event as a Cosmos one. - You can add more attributes in your event if the need arises.
- You can add more events to the response if you need or want to.
Adjust the unit test
The response has changed, so must the unit test:
...
mod tests {
...
- use cosmwasm_std::{testing, Addr, Binary, Response};
+ use cosmwasm_std::{testing, Addr, Binary, Event, Response};
...
fn test_execute() {
...
- assert_eq!(contract_result.unwrap(), Response::default());
+ let received_response = contract_result.unwrap();
+ let expected_event = Event::new("name-register")
+ .add_attribute("name", name.to_owned())
+ .add_attribute("owner", mocked_addr.to_string());
+ let expected_response = Response::default().add_event(expected_event);
+ assert_eq!(received_response, expected_response);
...
}
...
}
...Note that:
- The
assert_eq!macro does a deep equal between the received and expected responses. - Because you have only tested the function in isolation, the event name is not prefixed with
wasm-.
Adjust the mocked-app test
It too needs modifying:
- use cosmwasm_std::Addr;
+ use cosmwasm_std::{Addr, Event};
...
fn test_register() {
...
assert!(result.is_ok(), "Failed to register alice");
- let received_response = result.unwrap();
+ let expected_event = Event::new("wasm-name-register")
+ .add_attribute("name", name_alice.to_owned())
+ .add_attribute("owner", owner_addr_value.to_owned());
+ received_response.assert_event(&expected_event);
+ assert_eq!(received_response.data, None);
...
}
...Note that:
- Here, the received response is of type
AppResponse, which contains your new event, and may eventually contain other events that would be emitted by other smart contracts that may have been called as part ofExecuteMsg::Register. - This time, the mocked app prefixed the event with
wasm-. - The response has an
assert_eventfunction that callsassert!andhas_eventwith a nice message so that you don't have to write it yourself.
Conclusion
There is more to execution responses than events, as you will learn in subsequent sections.
At this stage, you should have something similar to the first-event branch, with this as the diff.