test api conformance

when provided with a non-counterexample, refineHypothesis should return false and not throw an exception.

Author: mtf90

algorithms/active/dhc/pom.xml

@@ -59,17 +59,17 @@ limitations under the License.
             <artifactId>automata-commons-util</artifactId>
         </dependency>
 
-        <dependency>
-            <groupId>org.checkerframework</groupId>
-            <artifactId>checker-qual</artifactId>
-        </dependency>
-
         <!-- build -->
         <dependency>
             <groupId>de.learnlib.tooling</groupId>
             <artifactId>annotations</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>org.checkerframework</groupId>
+            <artifactId>checker-qual</artifactId>
+        </dependency>
+
         <!-- test -->
         <dependency>
             <groupId>de.learnlib</groupId>

algorithms/active/dhc/src/main/java/de/learnlib/algorithm/dhc/mealy/MealyDHC.java

@@ -232,6 +232,10 @@ private void scheduleSuccessors(QueueElement<I, O> elem,
     public boolean refineHypothesis(DefaultQuery<I, Word<O>> ceQuery) {
         checkInternalState();
 
+        if (hypothesis.computeSuffixOutput(ceQuery.getPrefix(), ceQuery.getSuffix()).equals(ceQuery.getOutput())) {
+            return false;
+        }
+
         Collection<Word<I>> ceSuffixes = suffixFinder.findSuffixes(ceQuery, this, hypothesis, oracle);
 
         return addSuffixesUnchecked(ceSuffixes);

algorithms/active/procedural/src/main/java/de/learnlib/algorithm/procedural/sba/SBALearner.java

@@ -117,17 +117,21 @@ public void startLearning() {
     @Override
     public boolean refineHypothesis(DefaultQuery<I, Boolean> defaultQuery) {
 
+        if (!MQUtil.isCounterexample(defaultQuery, getHypothesisModel())) {
+            return false;
+        }
+
         assert this.alphabet.isReturnMatched(defaultQuery.getInput());
 
-        boolean changed = this.extractUsefulInformationFromCounterExample(defaultQuery);
+        boolean changed = extractUsefulInformationFromCounterExample(defaultQuery);
 
         while (refineHypothesisInternal(defaultQuery)) {
             changed = true;
         }
 
         ensureCallAndReturnClosure();
 
-        assert SBAs.isValid(this.getHypothesisModel());
+        assert SBAs.isValid(getHypothesisModel());
 
         return changed;
     }

algorithms/active/procedural/src/main/java/de/learnlib/algorithm/procedural/spa/SPALearner.java

@@ -106,9 +106,13 @@ public void startLearning() {
     @Override
     public boolean refineHypothesis(DefaultQuery<I, Boolean> defaultQuery) {
 
+        if (!MQUtil.isCounterexample(defaultQuery, getHypothesisModel())) {
+            return false;
+        }
+
         assert this.alphabet.isWellMatched(defaultQuery.getInput());
 
-        boolean changed = this.extractUsefulInformationFromCounterExample(defaultQuery);
+        boolean changed = extractUsefulInformationFromCounterExample(defaultQuery);
 
         while (refineHypothesisInternal(defaultQuery)) {
             changed = true;

algorithms/active/procedural/src/main/java/de/learnlib/algorithm/procedural/spmm/SPMMLearner.java

@@ -118,10 +118,14 @@ public void startLearning() {
     @Override
     public boolean refineHypothesis(DefaultQuery<I, Word<O>> defaultQuery) {
 
+        if (!MQUtil.isCounterexample(defaultQuery, getHypothesisModel())) {
+            return false;
+        }
+
         assert defaultQuery.getPrefix().isEmpty() : "Counterexamples need to provide full trace information";
         assert this.alphabet.isReturnMatched(defaultQuery.getInput()) : "Counterexample has unmatched return symbols";
 
-        boolean changed = this.extractUsefulInformationFromCounterExample(defaultQuery);
+        boolean changed = extractUsefulInformationFromCounterExample(defaultQuery);
 
         while (refineHypothesisInternal(defaultQuery)) {
             changed = true;

test-support/learner-it-support/pom.xml

@@ -65,6 +65,10 @@ limitations under the License.
             <groupId>net.automatalib</groupId>
             <artifactId>automata-api</artifactId>
         </dependency>
+        <dependency>
+            <groupId>net.automatalib</groupId>
+            <artifactId>automata-commons-util</artifactId>
+        </dependency>
         <dependency>
             <groupId>net.automatalib</groupId>
             <artifactId>automata-core</artifactId>

test-support/learner-it-support/src/main/java/de/learnlib/testsupport/it/learner/AbstractLearnerVariantITCase.java

@@ -15,21 +15,27 @@
  */
 package de.learnlib.testsupport.it.learner;
 
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
 import de.learnlib.algorithm.LearningAlgorithm;
 import de.learnlib.logging.Category;
 import de.learnlib.oracle.EquivalenceOracle;
 import de.learnlib.query.DefaultQuery;
 import de.learnlib.testsupport.example.LearningExample;
 import net.automatalib.alphabet.Alphabet;
 import net.automatalib.automaton.concept.FiniteRepresentation;
+import net.automatalib.automaton.concept.Output;
+import net.automatalib.common.util.random.RandomUtil;
 import net.automatalib.word.Word;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.testng.Assert;
 import org.testng.ITest;
 import org.testng.annotations.Test;
 
-abstract class AbstractLearnerVariantITCase<I, D, M extends FiniteRepresentation> implements ITest {
+abstract class AbstractLearnerVariantITCase<I, D, M extends FiniteRepresentation & Output<I, D>> implements ITest {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(AbstractLearnerVariantITCase.class);
 
@@ -81,6 +87,11 @@ public void testLearning() {
         Assert.assertEquals(hypothesis.size(), reference.size());
         Assert.assertNull(checkEquivalence(hypothesis), "Final hypothesis does not match reference automaton");
 
+        final List<I> trace = RandomUtil.sample(new Random(42), new ArrayList<>(alphabet), 5);
+        final D output = reference.computeOutput(trace);
+
+        Assert.assertFalse(learner.refineHypothesis(new DefaultQuery<>(Word.fromList(trace), output)));
+
         long duration = (System.nanoTime() - start) / NANOS_PER_MILLISECOND;
         LOGGER.info(Category.EVENT,
                     "Passed learner integration test {} ... took [{}]",

test-support/learner-it-support/src/main/java/de/learnlib/testsupport/it/learner/LearnerITUtil.java

@@ -37,6 +37,7 @@
 import net.automatalib.automaton.UniversalAutomaton;
 import net.automatalib.automaton.UniversalDeterministicAutomaton;
 import net.automatalib.automaton.concept.FiniteRepresentation;
+import net.automatalib.automaton.concept.Output;
 import net.automatalib.automaton.concept.SuffixOutput;
 import net.automatalib.automaton.procedural.SBA;
 import net.automatalib.automaton.procedural.SPA;
@@ -78,7 +79,7 @@ private LearnerITUtil() {
      *
      * @return the list of test cases, one for each example
      */
-    public static <I, D, A extends UniversalDeterministicAutomaton<?, I, ?, ?, ?>> List<UniversalDeterministicLearnerITCase<I, D, A>> createExampleITCases(
+    public static <I, D, A extends UniversalDeterministicAutomaton<?, I, ?, ?, ?> & Output<I, D>> List<UniversalDeterministicLearnerITCase<I, D, A>> createExampleITCases(
             UniversalDeterministicLearningExample<I, ? extends A> example,
             LearnerVariantListImpl<A, I, D> variants,
             EquivalenceOracle<? super A, I, D> eqOracle) {
@@ -192,7 +193,7 @@ public static <I> List<OneSEVPALearnerITCase<I>> createExampleITCases(OneSEVPALe
                 OneSEVPALearnerITCase::new);
     }
 
-    private static <I, D, M extends FiniteRepresentation, L extends LearningExample<I, ? extends M>, C extends AbstractLearnerVariantITCase<I, D, M>> List<C> createExampleITCasesInternal(
+    private static <I, D, M extends FiniteRepresentation & Output<I, D>, L extends LearningExample<I, ? extends M>, C extends AbstractLearnerVariantITCase<I, D, M>> List<C> createExampleITCasesInternal(
             L example,
             LearnerVariantListImpl<M, I, D> variants,
             EquivalenceOracle<? super M, I, D> eqOracle,
@@ -265,7 +266,7 @@ public static <I, D, A extends SuffixOutput<I, D>> List<PassiveLearnerVariantITC
     }
 
     @FunctionalInterface
-    private interface ITCaseBuilder<I, D, M extends FiniteRepresentation, L extends LearningExample<I, ? extends M>, C extends AbstractLearnerVariantITCase<I, D, M>> {
+    private interface ITCaseBuilder<I, D, M extends FiniteRepresentation & Output<I, D>, L extends LearningExample<I, ? extends M>, C extends AbstractLearnerVariantITCase<I, D, M>> {
 
         C build(LearnerVariant<M, I, D> variant, L example, EquivalenceOracle<? super M, I, D> eqOracle);
     }

test-support/learner-it-support/src/main/java/de/learnlib/testsupport/it/learner/UniversalDeterministicLearnerITCase.java

@@ -18,10 +18,11 @@
 import de.learnlib.oracle.EquivalenceOracle;
 import de.learnlib.testsupport.example.LearningExample.UniversalDeterministicLearningExample;
 import net.automatalib.automaton.UniversalDeterministicAutomaton;
+import net.automatalib.automaton.concept.Output;
 import net.automatalib.util.automaton.Automata;
 import net.automatalib.word.Word;
 
-public class UniversalDeterministicLearnerITCase<I, D, M extends UniversalDeterministicAutomaton<?, I, ?, ?, ?>>
+public class UniversalDeterministicLearnerITCase<I, D, M extends UniversalDeterministicAutomaton<?, I, ?, ?, ?> & Output<I, D>>
         extends AbstractLearnerVariantITCase<I, D, M> {
 
     private final UniversalDeterministicLearningExample<I, ? extends M> example;

test-support/learner-it-support/src/main/java/module-info.java

@@ -37,6 +37,7 @@
     requires de.learnlib.oracle.equivalence;
     requires de.learnlib.testsupport.example;
     requires net.automatalib.api;
+    requires net.automatalib.common.util;
     requires net.automatalib.util;
     requires org.slf4j;
     requires org.testng;