test: fix flake in TestMemPoolBatchPushUntrusted integration test

The flake was caused by improper waiting for certain chain operations
to finish:

- We didn't wait for messages to be registered as pushed
- We improperly waited for a fixed time (10 seconds) for messages to be
mined, which in the best case would wait longer than necessary and in the
worst case would cause the test to break.

What I did:
- fixed by waiting in a loop for "just enough time". This fixed the flake
and made the test run faster, on average, because we don't have unnecessary
waiting.
- I added a "circuit-breaker" where the wait loop will timeout after 10 seconds.

itests/mempool_test.go

@@ -3,6 +3,7 @@ package itests
 
 import (
 	"context"
+	"fmt"
 	"testing"
 	"time"
 
@@ -380,7 +381,7 @@ func TestMemPoolBatchPushUntrusted(t *testing.T) {
 	ctx := context.Background()
 	const blockTime = 100 * time.Millisecond
 	firstNode, _, _, ens := kit.EnsembleTwoOne(t, kit.MockProofs())
-	ens.InterconnectAll().BeginMining(blockTime)
+	ens.InterconnectAll()
 	kit.QuietMiningLogs()
 
 	sender := firstNode.DefaultKey.Address
@@ -416,18 +417,33 @@ func TestMemPoolBatchPushUntrusted(t *testing.T) {
 	_, err = firstNode.MpoolBatchPushUntrusted(ctx, sms)
 	require.NoError(t, err)
 
-	// check pending messages for address
+	// check pending messages for address, wait until they are all pushed
+	timeout := time.After(time.Second * 10)
+	for {
 		msgStatuses, err := firstNode.MpoolCheckPendingMessages(ctx, sender)
 		require.NoError(t, err)
-	require.Equal(t, totalMessages, len(msgStatuses))
+
+		if len(msgStatuses) == totalMessages {
 			for _, msgStatusList := range msgStatuses {
 				for _, status := range msgStatusList {
 					require.True(t, status.OK)
 				}
 			}
+			break
+		}
+
+		select {
+		case <-timeout:
+			t.Fatal("waiting for batch push timed out")
+		default:
+			fmt.Printf("waiting for %d more messages to be pushed\n", len(msgStatuses)-totalMessages)
+			time.Sleep(time.Millisecond * 100)
+		}
+	}
 
 	// verify messages should be the ones included in the next block
 	selected, _ := firstNode.MpoolSelect(ctx, types.EmptyTSK, 0)
+
 	for _, msg := range sms {
 		found := false
 		for _, selectedMsg := range selected {
@@ -439,17 +455,31 @@ func TestMemPoolBatchPushUntrusted(t *testing.T) {
 		require.True(t, found)
 	}
 
-	time.Sleep(10 * blockTime)
+	ens.BeginMining(blockTime)
 
+	// wait until pending messages are mined
+	timeout = time.After(time.Second * 10)
+	for {
 		// pool pending list should be empty
 		pending, err := firstNode.MpoolPending(context.TODO(), types.EmptyTSK)
 		require.NoError(t, err)
-	require.Equal(t, 0, len(pending))
 
+		if len(pending) == 0 {
 			// all messages should be added to the chain
 			for _, lookMsg := range sms {
 				msgLookup, err := firstNode.StateWaitMsg(ctx, lookMsg.Cid(), 3, api.LookbackNoLimit, true)
 				require.NoError(t, err)
 				require.NotNil(t, msgLookup)
 			}
+			break
+		}
+
+		select {
+		case <-timeout:
+			t.Fatal("waiting for pending messages to be mined timed out")
+		default:
+			fmt.Printf("waiting for %d more messages to be mined\n", len(pending))
+			time.Sleep(time.Millisecond * 100)
+		}
+	}
 }