rpc/client: rewrite the WaitForOneEvent helper (#7986) (#9550)

Update usage in tests.

Co-authored-by: M. J. Fromberger <fromberger@interchain.io>

rpc/client/event_test.go

@@ -41,12 +41,12 @@ func TestHeaderEvents(t *testing.T) {
 					}
 				})
 			}
-
-			evtTyp := types.EventNewBlockHeader
-			evt, err := client.WaitForOneEvent(c, evtTyp, waitForEventTimeout)
+			ectx, cancel := context.WithTimeout(ctx, waitForEventTimeout)
+			defer cancel()
+			query := types.QueryForEvent(types.EventNewBlockHeader).String()
+			var evt types.EventDataNewBlockHeader
+			err := client.WaitForOneEvent(ectx, c, query, &evt)
 			require.Nil(t, err, "%d: %+v", i, err)
-			_, ok := evt.(types.EventDataNewBlockHeader)
-			require.True(t, ok, "%d: %#v", i, evt)
 			// TODO: more checks...
 		})
 	}
@@ -141,17 +141,15 @@ func testTxEventsSent(t *testing.T, broadcastMethod string) {
 				}
 			}()
 
-			// and wait for confirmation
-			evt, err := client.WaitForOneEvent(c, types.EventTx, waitForEventTimeout)
+			// Wait for the transaction we sent to be confirmed.
+			query := fmt.Sprintf(`tm.event = '%s' AND tx.hash = '%X'`, types.EventTx, types.Tx(tx).Hash())
+			var evt types.EventDataTx
+			err := client.WaitForOneEvent(ctx, c, query, &evt)
 			require.Nil(t, err)
 
-			// and make sure it has the proper info
-			txe, ok := evt.(types.EventDataTx)
-			require.True(t, ok)
-
 			// make sure this is the proper tx
-			require.EqualValues(t, tx, txe.Tx)
-			require.True(t, txe.Result.IsOK())
+			require.EqualValues(t, tx, evt.Tx)
+			require.True(t, evt.Result.IsOK())
 		})
 	}
 }

rpc/client/helpers.go

@@ -2,10 +2,11 @@ package client
 
 import (
 	"context"
-	"errors"
+	"encoding/json"
 	"fmt"
 	"time"
 
+	coretypes "github.com/tendermint/tendermint/rpc/core/types"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -52,32 +53,24 @@ func WaitForHeight(c StatusClient, h int64, waiter Waiter) error {
 	return nil
 }
 
-// WaitForOneEvent subscribes to a websocket event for the given
-// event time and returns upon receiving it one time, or
-// when the timeout duration has expired.
-//
-// This handles subscribing and unsubscribing under the hood
-func WaitForOneEvent(c SubscriptionClient, evtTyp string, timeout time.Duration) (types.TMEventData, error) {
-	const subscriber = "helpers"
-	ctx, cancel := context.WithTimeout(context.Background(), timeout)
-	defer cancel()
-
-	// register for the next event of this type
-	eventCh, err := c.Subscribe(ctx, subscriber, types.QueryForEvent(evtTyp).String())
-	if err != nil {
-		return nil, fmt.Errorf("failed to subscribe: %w", err)
-	}
-	// make sure to unregister after the test is over
-	defer func() {
-		if deferErr := c.UnsubscribeAll(ctx, subscriber); deferErr != nil {
-			panic(deferErr)
+// WaitForOneEvent waits for the first event matching the given query on c, or
+// until ctx ends. It reports an error if ctx ends before a matching event is
+// received.
+func WaitForOneEvent(ctx context.Context, c EventsClient, query string, evt types.TMEventData) error {
+	for {
+		rsp, err := c.Events(ctx, &coretypes.RequestEvents{
+			Filter:   &coretypes.EventFilter{Query: query},
+			MaxItems: 1,
+			WaitTime: 10 * time.Second, // duration doesn't matter, limited by ctx timeout
+		})
+		if err != nil {
+			return err
+		} else if len(rsp.Items) == 0 {
+			continue // continue polling until ctx expires
 		}
-	}()
-
-	select {
-	case event := <-eventCh:
-		return event.Data, nil
-	case <-ctx.Done():
-		return nil, errors.New("timed out waiting for event")
+		if err := json.Unmarshal(rsp.Items[0].Data, evt); err != nil {
+			return err
+		}
+		return nil
 	}
 }