add coverage for event filtering

accounts/abi/bind/v2/lib.go

@@ -233,7 +233,10 @@ func FilterLogs[T any](instance *ContractInstance, opts *bind.FilterOpts, eventI
 	return &EventIterator[T]{unpack: unpack, logs: logs, sub: sub}, nil
 }
 
-// TODO: adding docs soon (jwasinger)
+// WatchLogs causes logs emitted with a given event id from a specified
+// contract to be intercepted, unpacked, and forwarded to sink.  If
+// unpack returns an error, the returned subscription is closed with the
+// error.
 func WatchLogs[T any](instance *ContractInstance, abi abi.ABI, opts *bind.WatchOpts, eventID common.Hash, unpack func(*types.Log) (*T, error), sink chan<- *T, topics ...[]any) (event.Subscription, error) {
 	backend := instance.Backend
 	c := bind.NewBoundContract(instance.Address, abi, backend, backend, backend)
@@ -270,7 +273,7 @@ func WatchLogs[T any](instance *ContractInstance, abi abi.ABI, opts *bind.WatchO
 
 // EventIterator is returned from FilterLogs and is used to iterate over the raw logs and unpacked data for events.
 type EventIterator[T any] struct {
-	Event *T // Event containing the contract specifics and raw log
+	event *T // event containing the contract specifics and raw log
 
 	unpack func(*types.Log) (*T, error) // Unpack function for the event
 
@@ -280,6 +283,11 @@ type EventIterator[T any] struct {
 	fail error                 // Occurred error to stop iteration
 }
 
+// Value returns the current value of the iterator, or nil if there isn't one.
+func (it *EventIterator[T]) Value() *T {
+	return it.event
+}
+
 // Next advances the iterator to the subsequent event, returning whether there
 // are any more events found. In case of a retrieval or parsing error, false is
 // returned and Error() can be queried for the exact failure.
@@ -297,7 +305,7 @@ func (it *EventIterator[T]) Next() bool {
 				it.fail = err
 				return false
 			}
-			it.Event = res
+			it.event = res
 			return true
 
 		default:
@@ -312,7 +320,7 @@ func (it *EventIterator[T]) Next() bool {
 			it.fail = err
 			return false
 		}
-		it.Event = res
+		it.event = res
 		return true
 
 	case err := <-it.sub.Err():

accounts/abi/bind/v2/lib_test.go

@@ -350,11 +350,6 @@ func TestEvents(t *testing.T) {
 	sub2, err := WatchLogs[events.CBasic2](&boundContract, *abi, watchOpts, events.CBasic2EventID(), unpackBasic2, newCBasic2Ch)
 	defer sub1.Unsubscribe()
 	defer sub2.Unsubscribe()
-	fmt.Printf("watching for event with id %x\n", events.CBasic1EventID())
-	fmt.Printf("watching for event with id %x\n", events.CBasic2EventID())
-	//wtf do I do with this subscriptions??
-	_ = sub1
-	_ = sub2
 
 	crtctInstance := &ContractInstance{
 		Address: res.Addrs[events.CMetaData.Pattern],
@@ -397,10 +392,36 @@ done:
 	if e2Count != 1 {
 		t.Fatalf("expected event type 2 count to be 1.  got %d", e2Count)
 	}
-	// commit a few blocks...
-	// now filter for the previously-emitted events.
 
+	// now, test that we can filter those events that were just caught through the subscription
+
+	filterOpts := &bind.FilterOpts{
+		Start:   0,
+		Context: context.Background(),
+	}
 	// TODO: test that returning error from unpack prevents event from being received by sink.
+	it, err := FilterLogs[events.CBasic1](crtctInstance, filterOpts, events.CBasic1EventID(), unpackBasic)
+	if err != nil {
+		t.Fatalf("error filtering logs %v\n", err)
+	}
+	it2, err := FilterLogs[events.CBasic2](crtctInstance, filterOpts, events.CBasic1EventID(), unpackBasic2)
+	if err != nil {
+		t.Fatalf("error filtering logs %v\n", err)
+	}
+	e1Count = 0
+	e2Count = 0
+	for it.Next() {
+		e1Count++
+	}
+	for it2.Next() {
+		e2Count++
+	}
+	if e2Count != 1 {
+		t.Fatalf("bad")
+	}
+	if e1Count != 1 {
+		t.Fatalf("bad")
+	}
 }
 
 func TestEventsUnpackFailure(t *testing.T) {
@@ -445,7 +466,7 @@ func TestEventsUnpackFailure(t *testing.T) {
 	}
 
 	unpackBasic := func(raw *types.Log) (*events.CBasic1, error) {
-		return nil, fmt.Errorf("could not unpack event")
+		return nil, fmt.Errorf("this error should stop the filter that uses this unpack.")
 	}
 	unpackBasic2 := func(raw *types.Log) (*events.CBasic2, error) {
 		return &events.CBasic2{
@@ -463,9 +484,6 @@ func TestEventsUnpackFailure(t *testing.T) {
 	sub2, err := WatchLogs[events.CBasic2](&boundContract, *abi, watchOpts, events.CBasic2EventID(), unpackBasic2, newCBasic2Ch)
 	defer sub1.Unsubscribe()
 	defer sub2.Unsubscribe()
-	//wtf do I do with this subscriptions??
-	_ = sub1
-	_ = sub2
 
 	crtctInstance := &ContractInstance{
 		Address: res.Addrs[events.CMetaData.Pattern],