test: Improve performance of continuous assertions

platform-sdk/consensus-hashgraph-impl/src/testFixtures/java/org/hiero/consensus/hashgraph/impl/test/fixtures/consensus/ConsensusOutput.java

@@ -4,7 +4,6 @@
 import edu.umd.cs.findbugs.annotations.NonNull;
 import java.util.ArrayList;
 import java.util.Comparator;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
@@ -20,21 +19,21 @@
  * Stores all output of consensus used in testing. This output can be used to validate consensus results.
  */
 public class ConsensusOutput implements Clearable {
-    private final LinkedList<ConsensusRound> consensusRounds;
-    private final LinkedList<PlatformEvent> preConsensusEvents;
-    private final LinkedList<PlatformEvent> addedEvents;
-    private final LinkedList<PlatformEvent> staleEvents;
+    private final List<ConsensusRound> consensusRounds;
+    private final List<PlatformEvent> preConsensusEvents;
+    private final List<PlatformEvent> addedEvents;
+    private final List<PlatformEvent> staleEvents;
 
     private EventWindow eventWindow;
 
     /**
      * Creates a new instance.
      */
     public ConsensusOutput() {
-        addedEvents = new LinkedList<>();
-        preConsensusEvents = new LinkedList<>();
-        consensusRounds = new LinkedList<>();
-        staleEvents = new LinkedList<>();
+        addedEvents = new ArrayList<>();
+        preConsensusEvents = new ArrayList<>();
+        consensusRounds = new ArrayList<>();
+        staleEvents = new ArrayList<>();
 
         eventWindow = EventWindow.getGenesisEventWindow();
     }
@@ -60,9 +59,9 @@ public void consensusRound(@NonNull final ConsensusRound consensusRound) {
     }
 
     /**
-     * @return a queue of all events that have been marked as stale
+     * @return a list of all events that have been marked as stale
      */
-    public @NonNull LinkedList<PlatformEvent> getStaleEvents() {
+    public @NonNull List<PlatformEvent> getStaleEvents() {
         return staleEvents;
     }
 
@@ -76,9 +75,9 @@ public void consensusRound(@NonNull final ConsensusRound consensusRound) {
     }
 
     /**
-     * @return a queue of all rounds that have reached consensus
+     * @return a list of all rounds that have reached consensus
      */
-    public @NonNull LinkedList<ConsensusRound> getConsensusRounds() {
+    public @NonNull List<ConsensusRound> getConsensusRounds() {
         return consensusRounds;
     }
 
@@ -92,7 +91,7 @@ public void consensusRound(@NonNull final ConsensusRound consensusRound) {
         return consensusRounds.getLast();
     }
 
-    public @NonNull LinkedList<PlatformEvent> getAddedEvents() {
+    public @NonNull List<PlatformEvent> getAddedEvents() {
         return addedEvents;
     }
 

platform-sdk/consensus-hashgraph-impl/src/testFixtures/java/org/hiero/consensus/hashgraph/impl/test/fixtures/consensus/GenerateConsensus.java

@@ -6,7 +6,6 @@
 import com.swirlds.metrics.api.Metrics;
 import edu.umd.cs.findbugs.annotations.NonNull;
 import java.util.ArrayList;
-import java.util.Deque;
 import java.util.List;
 import java.util.stream.IntStream;
 import org.hiero.consensus.hashgraph.impl.test.fixtures.event.generator.StandardGraphGenerator;
@@ -31,7 +30,7 @@ private GenerateConsensus() {}
      * @param seed the seed to use
      * @return consensus rounds
      */
-    public static Deque<ConsensusRound> generateConsensusRounds(
+    public static List<ConsensusRound> generateConsensusRounds(
             @NonNull final Configuration configuration,
             @NonNull final Metrics metrics,
             @NonNull final Time time,

platform-sdk/consensus-hashgraph-impl/src/testFixtures/java/org/hiero/consensus/hashgraph/impl/test/fixtures/consensus/TestIntake.java

@@ -165,9 +165,9 @@ public void addEvent(@NonNull final PlatformEvent event) {
     }
 
     /**
-     * @return a queue of all rounds that have reached consensus
+     * @return a list of all rounds that have reached consensus
      */
-    public @NonNull LinkedList<ConsensusRound> getConsensusRounds() {
+    public @NonNull List<ConsensusRound> getConsensusRounds() {
         return output.getConsensusRounds();
     }
 

platform-sdk/consensus-hashgraph-impl/src/testFixtures/java/org/hiero/consensus/hashgraph/impl/test/fixtures/consensus/framework/ConsensusTestNode.java

@@ -8,8 +8,8 @@
 import com.swirlds.config.api.Configuration;
 import com.swirlds.metrics.api.Metrics;
 import edu.umd.cs.findbugs.annotations.NonNull;
-import java.util.LinkedList;
-import java.util.Objects;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Random;
 import org.hiero.consensus.hashgraph.impl.test.fixtures.consensus.ConsensusOutput;
 import org.hiero.consensus.hashgraph.impl.test.fixtures.consensus.TestIntake;
@@ -65,9 +65,8 @@ public ConsensusTestNode(@NonNull final EventEmitter eventEmitter, @NonNull fina
     public void restart() {
         // clear all generators
         eventEmitter.reset();
-        final ConsensusSnapshot snapshot = Objects.requireNonNull(
-                        getOutput().getConsensusRounds().peekLast())
-                .getSnapshot();
+        final ConsensusSnapshot snapshot =
+                getOutput().getConsensusRounds().getLast().getSnapshot();
         intake.reset();
         intake.loadSnapshot(snapshot);
     }
@@ -78,13 +77,12 @@ public void restart() {
      */
     public void removeNode(@NonNull final NodeId nodeId) {
         eventEmitter.getGraphGenerator().removeNode(nodeId);
-        final ConsensusSnapshot snapshot = Objects.requireNonNull(
-                        getOutput().getConsensusRounds().peekLast())
-                .getSnapshot();
+        final ConsensusSnapshot snapshot =
+                getOutput().getConsensusRounds().getLast().getSnapshot();
         intake.loadSnapshot(snapshot);
         // the above will clear all events from the linker and consensus, so we need to add all non-ancient events
         // adding events will also add the events to the output, so we make a copy of the list and add them back
-        final LinkedList<PlatformEvent> added = new LinkedList<>(getOutput().getAddedEvents());
+        final List<PlatformEvent> added = new ArrayList<>(getOutput().getAddedEvents());
         getOutput().getAddedEvents().clear();
         for (final PlatformEvent e : added) {
             intake.addEvent(e.copyGossipedData());
@@ -113,8 +111,7 @@ public void removeNode(@NonNull final NodeId nodeId) {
                         time,
                         newEmitter.getGraphGenerator().getRoster()));
         consensusTestNode.intake.loadSnapshot(
-                Objects.requireNonNull(getOutput().getConsensusRounds().peekLast())
-                        .getSnapshot());
+                getOutput().getConsensusRounds().getLast().getSnapshot());
 
         assertThat(consensusTestNode.intake.getConsensusRounds())
                 .withFailMessage("we should not have reached consensus yet")

platform-sdk/consensus-hashgraph-impl/src/testFixtures/java/org/hiero/consensus/hashgraph/impl/test/fixtures/consensus/framework/validation/ConsensusRoundValidator.java

@@ -34,7 +34,7 @@ private ConsensusRoundValidator() {}
     public static void validate(
             @NonNull final List<ConsensusRound> rounds1, @NonNull final List<ConsensusRound> rounds2) {
         assertThat(rounds1)
-                .withFailMessage(String.format(
+                .withFailMessage(() -> String.format(
                         "The number of consensus rounds is not the same."
                                 + "first argument has %d rounds, second has %d rounds",
                         rounds1.size(), rounds2.size()))

platform-sdk/consensus-hashgraph-impl/src/testFixtures/java/org/hiero/consensus/hashgraph/impl/test/fixtures/consensus/framework/validation/NumberOfConsensusRoundsValidation.java

@@ -14,10 +14,10 @@ public record NumberOfConsensusRoundsValidation(int numberOfRounds) implements C
     @Override
     public void validate(@NonNull final ConsensusOutput output1, @NonNull final ConsensusOutput output2) {
         for (final ConsensusOutput output : List.of(output1, output2)) {
-            Assertions.assertThat(output.getConsensusRounds().size())
+            final int actualRounds = output.getConsensusRounds().size();
+            Assertions.assertThat(actualRounds)
                     .withFailMessage(
-                            "Expected %d rounds, but got %d",
-                            numberOfRounds, output.getConsensusRounds().size())
+                            () -> String.format("Expected %d rounds, but got %d", numberOfRounds, actualRounds))
                     .isEqualTo(numberOfRounds);
         }
     }

platform-sdk/consensus-hashgraph-impl/src/testFixtures/java/org/hiero/consensus/hashgraph/impl/test/fixtures/consensus/framework/validation/OutputEventRatioValidation.java

@@ -101,12 +101,12 @@ public void validate(@NonNull final ConsensusOutput output1, @NonNull final Cons
         final double consensusRatio = ((double) numConsensus) / allEvents1.size();
 
         assertThat(consensusRatio)
-                .withFailMessage(String.format(
+                .withFailMessage(() -> String.format(
                         "Consensus ratio %s is less than the expected minimum %s",
                         consensusRatio, minimumConsensusRatio))
                 .isGreaterThanOrEqualTo(minimumConsensusRatio);
         assertThat(consensusRatio)
-                .withFailMessage(String.format(
+                .withFailMessage(() -> String.format(
                         "Consensus ratio %s is more than the expected maximum %s",
                         consensusRatio, maximumConsensusRatio))
                 .isLessThanOrEqualTo(maximumConsensusRatio);
@@ -115,11 +115,11 @@ public void validate(@NonNull final ConsensusOutput output1, @NonNull final Cons
         final double staleRatio = ((double) output1.getStaleEvents().size()) / allEvents1.size();
 
         assertThat(staleRatio)
-                .withFailMessage(String.format(
+                .withFailMessage(() -> String.format(
                         "Stale ratio %s is less than the expected minimum %s", staleRatio, minimumStaleRatio))
                 .isGreaterThanOrEqualTo(minimumStaleRatio);
         assertThat(staleRatio)
-                .withFailMessage(String.format(
+                .withFailMessage(() -> String.format(
                         "Stale ratio %s is more than the expected maximum %s", staleRatio, maximumStaleRatio))
                 .isLessThanOrEqualTo(maximumStaleRatio);
     }

platform-sdk/consensus-hashgraph-impl/src/testFixtures/java/org/hiero/consensus/hashgraph/impl/test/fixtures/consensus/framework/validation/OutputNoEventsLostValidation.java

@@ -5,13 +5,15 @@
 
 import com.swirlds.config.extensions.test.fixtures.TestConfigBuilder;
 import edu.umd.cs.findbugs.annotations.NonNull;
+import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
 import org.hiero.base.crypto.Hash;
 import org.hiero.base.crypto.Hashable;
 import org.hiero.consensus.hashgraph.config.ConsensusConfig;
 import org.hiero.consensus.hashgraph.impl.test.fixtures.consensus.ConsensusOutput;
 import org.hiero.consensus.model.event.PlatformEvent;
+import org.hiero.consensus.model.hashgraph.ConsensusRound;
 import org.hiero.consensus.round.RoundCalculationUtils;
 
 @SuppressWarnings("unused") // issue tracked #6998
@@ -29,31 +31,33 @@ private OutputNoEventsLostValidation() {}
      * neither, so they are not checked.
      */
     public void validate(@NonNull final ConsensusOutput output, @NonNull final ConsensusOutput ignored) {
+        final List<ConsensusRound> consensusRounds = output.getConsensusRounds();
+        if (consensusRounds.isEmpty()) {
+            // no consensus reached, nothing to check
+            return;
+        }
+
         final Map<Hash, PlatformEvent> stale =
                 output.getStaleEvents().stream().collect(Collectors.toMap(Hashable::getHash, e -> e));
-        final Map<Hash, PlatformEvent> cons = output.getConsensusRounds().stream()
+        final Map<Hash, PlatformEvent> cons = consensusRounds.stream()
                 .flatMap(r -> r.getConsensusEvents().stream())
                 .collect(Collectors.toMap(PlatformEvent::getHash, e -> e));
-        if (output.getConsensusRounds().isEmpty()) {
-            // no consensus reached, nothing to check
-            return;
-        }
         final long nonAncientThreshold = RoundCalculationUtils.getAncientThreshold(
-                CONFIG.roundsNonAncient(), output.getConsensusRounds().getLast().getSnapshot());
+                CONFIG.roundsNonAncient(), consensusRounds.getLast().getSnapshot());
 
         for (final PlatformEvent event : output.getAddedEvents()) {
             if (event.getBirthRound() >= nonAncientThreshold) {
                 // non-ancient events are not checked
                 continue;
             }
-            if (stale.containsKey(event.getHash()) == cons.containsKey(event.getHash())) {
+            final Hash hash = event.getHash();
+            final boolean isStale = stale.containsKey(hash);
+            final boolean isConsensus = cons.containsKey(hash);
+            if (isStale == isConsensus) {
                 fail(String.format(
                         "An ancient event should be either stale or consensus, but not both!\n"
                                 + "nonAncientGen=%d, Event %s, stale=%s, consensus=%s",
-                        nonAncientThreshold,
-                        event.getDescriptor(),
-                        stale.containsKey(event.getHash()),
-                        cons.containsKey(event.getHash())));
+                        nonAncientThreshold, event.getDescriptor(), isStale, isConsensus));
             }
         }
     }

platform-sdk/consensus-hashgraph-impl/src/testFixtures/java/org/hiero/consensus/hashgraph/impl/test/fixtures/consensus/framework/validation/RoundAncientThresholdIncreasesValidation.java

@@ -26,16 +26,20 @@ public void validate(@NonNull final List<ConsensusRound> rounds) {
             return;
         }
 
-        for (int i = 1; i < rounds.size(); i++) {
+        // Carry the previous round's threshold across iterations so each round's snapshot chain is
+        // resolved only once instead of once as "current" and again as "previous".
+        MinimumJudgeInfo previousThresholdInfo =
+                rounds.getFirst().getSnapshot().minimumJudgeInfoList().getLast();
+        for (int i = 1, n = rounds.size(); i < n; i++) {
 
-            final MinimumJudgeInfo previousThresholdInfo =
-                    rounds.get(i - 1).getSnapshot().minimumJudgeInfoList().getLast();
             final MinimumJudgeInfo currentThresholdInfo =
                     rounds.get(i).getSnapshot().minimumJudgeInfoList().getLast();
 
             assertThat(currentThresholdInfo.minimumJudgeBirthRound())
                     .withFailMessage("the ancient threshold should never decrease")
                     .isGreaterThanOrEqualTo(previousThresholdInfo.minimumJudgeBirthRound());
+
+            previousThresholdInfo = currentThresholdInfo;
         }
     }
 }

platform-sdk/consensus-hashgraph-impl/src/testFixtures/java/org/hiero/consensus/hashgraph/impl/test/fixtures/consensus/framework/validation/RoundInternalConsistencyValidation.java

@@ -24,7 +24,7 @@ public void validate(@NonNull final List<ConsensusRound> rounds) {
             final MinimumJudgeInfo minimumJudgeInfo =
                     round.getSnapshot().minimumJudgeInfoList().getLast();
             assertThat(round.getRoundNum())
-                    .withFailMessage(String.format(
+                    .withFailMessage(() -> String.format(
                             "the last threshold should be equal for the current round %d", round.getRoundNum()))
                     .isEqualTo(minimumJudgeInfo.round());
 

platform-sdk/consensus-hashgraph-impl/src/testFixtures/java/org/hiero/consensus/hashgraph/impl/test/fixtures/consensus/framework/validation/RoundInternalEqualityValidation.java

@@ -6,6 +6,7 @@
 import edu.umd.cs.findbugs.annotations.NonNull;
 import java.util.Iterator;
 import java.util.Objects;
+import java.util.function.Supplier;
 import org.hiero.consensus.model.event.PlatformEvent;
 import org.hiero.consensus.model.hashgraph.ConsensusRound;
 
@@ -26,15 +27,15 @@ public void validate(@NonNull final ConsensusRound round1, @NonNull final Consen
         final long firstRoundNumber = round1.getRoundNum();
         final long secondRoundNumber = round2.getRoundNum();
         assertThat(round1.getRoundNum())
-                .withFailMessage(String.format(
+                .withFailMessage(() -> String.format(
                         "round diff at rounds with numbers %d and %d", firstRoundNumber, secondRoundNumber))
                 .isEqualTo(round2.getRoundNum());
         assertThat(round1.getEventCount())
-                .withFailMessage(String.format(
+                .withFailMessage(() -> String.format(
                         "event number diff at rounds with numbers %d and %d", firstRoundNumber, secondRoundNumber))
                 .isEqualTo(round2.getEventCount());
         assertThat(round1.getSnapshot())
-                .withFailMessage(String.format(
+                .withFailMessage(() -> String.format(
                         "snapshot diff at rounds with numbers %d and %d", firstRoundNumber, secondRoundNumber))
                 .isEqualTo(round2.getSnapshot());
         final Iterator<PlatformEvent> evIt1 = round1.getConsensusEvents().iterator();
@@ -43,20 +44,21 @@ public void validate(@NonNull final ConsensusRound round1, @NonNull final Consen
         while (evIt1.hasNext() && evIt2.hasNext()) {
             final PlatformEvent e1 = evIt1.next();
             final PlatformEvent e2 = evIt2.next();
+            final int index = eventIndex;
             assertThat(e1.getConsensusData())
-                    .withFailMessage(String.format(
+                    .withFailMessage(() -> String.format(
                             "output:1, roundNumberFromFirstNode:%d, roundNumberFromSecondRound:%d, eventIndex%d is not consensus",
-                            firstRoundNumber, secondRoundNumber, eventIndex))
+                            firstRoundNumber, secondRoundNumber, index))
                     .isNotNull();
             assertThat(e2.getConsensusData())
-                    .withFailMessage(String.format(
+                    .withFailMessage(() -> String.format(
                             "output:1, roundNumberFromFirstNode:%d, roundNumberFromSecondRound:%d, eventIndex%d is not consensus",
-                            firstRoundNumber, secondRoundNumber, eventIndex))
+                            firstRoundNumber, secondRoundNumber, index))
                     .isNotNull();
             assertConsensusEvents(
-                    String.format(
+                    () -> String.format(
                             "roundNumberFromFirstNode:%d, roundNumberFromSecondRound:%d, event index %d",
-                            firstRoundNumber, secondRoundNumber, eventIndex),
+                            firstRoundNumber, secondRoundNumber, index),
                     e1,
                     e2);
             eventIndex++;
@@ -67,16 +69,16 @@ public void validate(@NonNull final ConsensusRound round1, @NonNull final Consen
      * Assert that two events are equal. If they are not equal then cause the test to fail and print
      * a meaningful error message.
      *
-     * @param description a string that is printed if the events are unequal
+     * @param description supplies a string that is printed if the events are unequal; only evaluated on failure
      * @param e1 the first event
      * @param e2 the second event
      */
     private static void assertConsensusEvents(
-            final String description, final PlatformEvent e1, final PlatformEvent e2) {
+            final Supplier<String> description, final PlatformEvent e1, final PlatformEvent e2) {
         final boolean equal = Objects.equals(e1, e2);
         if (!equal) {
             final StringBuilder sb = new StringBuilder();
-            sb.append(description).append("\n");
+            sb.append(description.get()).append("\n");
             sb.append("Events are not equal:\n");
             sb.append("Event 1: ").append(e1).append("\n");
             sb.append("Event 2: ").append(e2).append("\n");