tapgarden: extend time window for expected DeriveNextKey calls

Increase the allowed time window during which the expected number of
DeriveNextKey calls can occur. This helps accommodate timing
variations and reduces test flakiness.

Author: ffranr

tapgarden/planter_test.go

@@ -309,7 +309,18 @@ func (t *mintingTestHarness) queueSeedlingsInBatch(isFunded bool,
 		// The received update should be a state of MintingStateSeed.
 		require.Equal(t, tapgarden.MintingStateSeed, update.NewState)
 
-		t.keyRing.AssertNumberOfCalls(t, "DeriveNextKey", keyCount)
+		require.Eventually(t, func() bool {
+			// Assert that the key ring method DeriveNextKey was
+			// called the expected number of times.
+			count := 0
+			for _, call := range t.keyRing.Calls {
+				if call.Method == "DeriveNextKey" {
+					count++
+				}
+			}
+
+			return count == keyCount
+		}, defaultTimeout, wait.PollInterval)
 	}
 }