Explicit assumptions in packet_from_tx_search_response

[vitorenesduarte]

Closes: #XXX

Description

This PR makes the following two assumptions from packet_from_tx_search_response explicit:

• the number of returned transactions is at most 1
• if a transaction is returned, then there's exactly 1 transaction event matching the packet query

To make the second assumption explicit, it's required that we iterate all transactions events, which may come with a performance cost. To alleviate this, we're now only trying to parse channel events with ChannelEvents::try_from_tx(&e) instead of the more general from_tx_response_event(e).

This is a follow-up to #613.

---

For contributor use:

• Updated the Unreleased section of CHANGELOG.md with the issue.
• If applicable: Unit tests written, added test to CI.
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Updated relevant documentation (docs/) and code comments.
• Re-reviewed Files changed in the Github PR explorer.

[codecov-io]

Codecov Report

Merging #617 (3e95014) into master (b1b37f5) will increase coverage by 30.8%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master    #617      +/-   ##
=========================================
+ Coverage    13.6%   44.5%   +30.8%     
=========================================
  Files          69     144      +75     
  Lines        3752    9550    +5798     
  Branches     1374       0    -1374     
=========================================
+ Hits          513    4255    +3742     
- Misses       2618    5295    +2677     
+ Partials      621       0     -621     

Impacted Files	Coverage Δ
modules/src/address.rs	100.0% <ø> (ø)
...application/ics20_fungible_token_transfer/error.rs	0.0% <ø> (ø)
...pplication/ics20_fungible_token_transfer/events.rs	0.0% <ø> (ø)
...ion/ics20_fungible_token_transfer/msgs/transfer.rs	0.0% <ø> (ø)
modules/src/events.rs	0.0% <ø> (ø)
modules/src/handler.rs	100.0% <ø> (ø)
modules/src/ics02_client/client_def.rs	48.3% <ø> (ø)
modules/src/ics02_client/client_type.rs	79.1% <ø> (+31.5%)	⬆️
modules/src/ics02_client/context.rs	100.0% <ø> (ø)
modules/src/ics02_client/error.rs	100.0% <ø> (ø)
... and 246 more

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[ancazamfir]

This doesn't seem right. It is true that there is one single transaction but it may include multiple events. I think what was there before was correct:

Suggested change

	assert_eq!(
	e.type_str,
	request.event_id.as_str(),
	"packet_from_tx_search_response: unexpected event type"
	);
	if e.type_str != request.event_id.as_str() {
	continue;
	}

[vitorenesduarte]

Thanks! This was the reason why the tests were failing. Fixed in b0a9aa0.

[ancazamfir]

Looks good, thanks Vitor!