add tests for PropertyOracles

to check the problems reported in LearnLib/automatalib#46

oracles/property-oracles/pom.xml

@@ -37,6 +37,42 @@
         </dependency>
 
         <!-- test -->
+        <dependency>
+            <groupId>de.learnlib</groupId>
+            <artifactId>learnlib-emptiness-oracles</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>de.learnlib</groupId>
+            <artifactId>learnlib-equivalence-oracles</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>de.learnlib.testsupport</groupId>
+            <artifactId>learnlib-learning-examples</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>de.learnlib</groupId>
+            <artifactId>learnlib-membership-oracles</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>net.automatalib</groupId>
+            <artifactId>automata-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>net.automatalib</groupId>
+            <artifactId>automata-modelchecking-ltsmin</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>net.automatalib</groupId>
+            <artifactId>automata-util</artifactId>
+            <scope>test</scope>
+        </dependency>
+
         <dependency>
             <groupId>org.testng</groupId>
             <artifactId>testng</artifactId>

oracles/property-oracles/src/test/java/de/learnlib/oracle/property/MealyPropertyOracleTest.java

@@ -0,0 +1,127 @@
+/* Copyright (C) 2013-2021 TU Dortmund
+ * This file is part of LearnLib, http://www.learnlib.de/.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.learnlib.oracle.property;
+
+import java.util.function.Function;
+
+import de.learnlib.api.oracle.EmptinessOracle.MealyEmptinessOracle;
+import de.learnlib.api.oracle.InclusionOracle.MealyInclusionOracle;
+import de.learnlib.api.oracle.LassoEmptinessOracle.MealyLassoEmptinessOracle;
+import de.learnlib.api.oracle.MembershipOracle.MealyMembershipOracle;
+import de.learnlib.api.oracle.OmegaMembershipOracle.MealyOmegaMembershipOracle;
+import de.learnlib.api.oracle.PropertyOracle.MealyPropertyOracle;
+import de.learnlib.api.query.DefaultQuery;
+import de.learnlib.examples.mealy.ExampleTinyMealy;
+import de.learnlib.oracle.emptiness.MealyBFEmptinessOracle;
+import de.learnlib.oracle.emptiness.MealyLassoEmptinessOracleImpl;
+import de.learnlib.oracle.equivalence.MealyBFInclusionOracle;
+import de.learnlib.oracle.membership.SimulatorOmegaOracle.MealySimulatorOmegaOracle;
+import de.learnlib.oracle.membership.SimulatorOracle.MealySimulatorOracle;
+import net.automatalib.automata.transducers.MealyMachine;
+import net.automatalib.automata.transducers.impl.compact.CompactMealy;
+import net.automatalib.modelcheckers.ltsmin.LTSminUtil;
+import net.automatalib.modelcheckers.ltsmin.LTSminVersion;
+import net.automatalib.modelcheckers.ltsmin.ltl.LTSminLTLIOBuilder;
+import net.automatalib.modelcheckers.ltsmin.monitor.LTSminMonitorIOBuilder;
+import net.automatalib.modelchecking.ModelChecker.MealyModelChecker;
+import net.automatalib.modelchecking.ModelCheckerLasso.MealyModelCheckerLasso;
+import net.automatalib.util.automata.builders.AutomatonBuilders;
+import net.automatalib.words.Alphabet;
+import net.automatalib.words.Word;
+import net.automatalib.words.impl.Alphabets;
+import org.testng.Assert;
+import org.testng.SkipException;
+import org.testng.annotations.Test;
+
+public class MealyPropertyOracleTest {
+
+    private static final Function<String, Character> EDGE_PARSER = s -> s.charAt(0);
+
+    // @formatter:off
+    private static final CompactMealy<Character, Character> HYP =
+            AutomatonBuilders.<Character, Character>newMealy(Alphabets.singleton('a'))
+                             .withInitial("q0")
+                             .from("q0").on('a').withOutput('1').loop()
+                             .create();
+    // @formatter:on
+
+    @Test
+    public void testTinyExample() {
+        if (!LTSminUtil.supports(LTSminVersion.of(3, 0, 0))) {
+            throw new SkipException("LTSmin is not installed in the proper version");
+        }
+
+        final ExampleTinyMealy example = ExampleTinyMealy.createExample();
+        final Alphabet<Character> inputAlphabet = example.getAlphabet();
+
+        final MealyMachine<?, Character, ?, Character> sys = example.getReferenceAutomaton();
+
+        final MealyOmegaMembershipOracle<?, Character, Character> omqo = new MealySimulatorOmegaOracle<>(sys);
+        final MealyMembershipOracle<Character, Character> mqo = omqo.getMembershipOracle();
+
+        final MealyLassoEmptinessOracle<Character, Character> emptinessOracle =
+                new MealyLassoEmptinessOracleImpl<>(omqo);
+        final MealyInclusionOracle<Character, Character> inclusionOracle = new MealyBFInclusionOracle<>(mqo, 1.0);
+
+        final MealyModelCheckerLasso<Character, Character, String> modelChecker =
+                new LTSminLTLIOBuilder<Character, Character>().withString2Input(EDGE_PARSER)
+                                                              .withString2Output(EDGE_PARSER)
+                                                              .create();
+
+        final MealyPropertyOracle<Character, Character, String> propertyOracle =
+                new MealyLassoPropertyOracle<>("X output==\"2\"", inclusionOracle, emptinessOracle, modelChecker);
+
+        final DefaultQuery<Character, Word<Character>> ce = propertyOracle.findCounterExample(HYP, inputAlphabet);
+
+        Assert.assertNotNull(ce);
+        Assert.assertNotEquals(ce.getOutput(), HYP.computeOutput(ce.getInput()));
+    }
+
+    /**
+     * Test-case issue <a href="https://github.com/LearnLib/automatalib/issues/46">#46</a>.
+     */
+    @Test
+    public void testIssue46() {
+        if (!LTSminUtil.supports(LTSminVersion.of(3, 1, 0))) {
+            throw new SkipException("LTSmin is not installed in the proper version");
+        }
+
+        final ExampleTinyMealy example = ExampleTinyMealy.createExample();
+        final Alphabet<Character> inputAlphabet = example.getAlphabet();
+        final MealyMachine<?, Character, ?, Character> sys = example.getReferenceAutomaton();
+
+        final int multiplier = 1;
+        final MealyMembershipOracle<Character, Character> mqo = new MealySimulatorOracle<>(sys);
+
+        final MealyEmptinessOracle<Character, Character> emptinessOracle =
+                new MealyBFEmptinessOracle<>(mqo, multiplier);
+        final MealyInclusionOracle<Character, Character> inclusionOracle =
+                new MealyBFInclusionOracle<>(mqo, multiplier);
+
+        final MealyModelChecker<Character, Character, String, MealyMachine<?, Character, ?, Character>> modelChecker =
+                new LTSminMonitorIOBuilder<Character, Character>().withString2Input(EDGE_PARSER)
+                                                                  .withString2Output(EDGE_PARSER)
+                                                                  .create();
+
+        final MealyFinitePropertyOracle<Character, Character, String> propertyOracle =
+                new MealyFinitePropertyOracle<>("X (output == \"2\")", inclusionOracle, emptinessOracle, modelChecker);
+
+        final DefaultQuery<Character, Word<Character>> ce = propertyOracle.findCounterExample(HYP, inputAlphabet);
+
+        Assert.assertNotNull(ce);
+        Assert.assertNotEquals(ce.getOutput(), HYP.computeOutput(ce.getInput()));
+    }
+}