Merge main into develop

core/queryalgebra/evaluation/src/test/java/org/eclipse/rdf4j/query/algebra/evaluation/iterator/PathIterationTest.java

@@ -0,0 +1,155 @@
+/*******************************************************************************
+ * Copyright (c) 2023 Eclipse RDF4J contributors.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Distribution License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *******************************************************************************/
+package org.eclipse.rdf4j.query.algebra.evaluation.iterator;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.eclipse.rdf4j.common.iteration.CloseableIteration;
+import org.eclipse.rdf4j.common.iteration.CloseableIteratorIteration;
+import org.eclipse.rdf4j.model.IRI;
+import org.eclipse.rdf4j.model.Model;
+import org.eclipse.rdf4j.model.Resource;
+import org.eclipse.rdf4j.model.Statement;
+import org.eclipse.rdf4j.model.Value;
+import org.eclipse.rdf4j.model.ValueFactory;
+import org.eclipse.rdf4j.model.impl.LinkedHashModel;
+import org.eclipse.rdf4j.model.impl.SimpleValueFactory;
+import org.eclipse.rdf4j.model.vocabulary.RDFS;
+import org.eclipse.rdf4j.query.BindingSet;
+import org.eclipse.rdf4j.query.QueryEvaluationException;
+import org.eclipse.rdf4j.query.algebra.StatementPattern;
+import org.eclipse.rdf4j.query.algebra.StatementPattern.Scope;
+import org.eclipse.rdf4j.query.algebra.TupleExpr;
+import org.eclipse.rdf4j.query.algebra.Var;
+import org.eclipse.rdf4j.query.algebra.evaluation.QueryBindingSet;
+import org.eclipse.rdf4j.query.algebra.evaluation.TripleSource;
+import org.eclipse.rdf4j.query.algebra.evaluation.impl.DefaultEvaluationStrategy;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class PathIterationTest {
+
+	private DefaultEvaluationStrategy evaluator;
+	private static final ValueFactory vf = SimpleValueFactory.getInstance();
+	private static final Resource one = vf.createIRI("https://example.org/", "one");
+	private static final Resource two = vf.createIRI("https://example.org/", "two");
+	private static final Resource three = vf.createIRI("https://example.org/", "three");
+
+	@BeforeEach
+	public void setUp() {
+		Model m = new LinkedHashModel();
+		m.add(one, RDFS.SUBCLASSOF, two);
+		m.add(two, RDFS.SUBCLASSOF, three);
+
+		TripleSource ts = new TripleSource() {
+
+			@Override
+			public CloseableIteration<? extends Statement, QueryEvaluationException> getStatements(Resource subj,
+					IRI pred, Value obj, Resource... contexts) throws QueryEvaluationException {
+				return new CloseableIteratorIteration<>(m.getStatements(subj, pred, obj, contexts).iterator());
+			}
+
+			@Override
+			public ValueFactory getValueFactory() {
+				return vf;
+			}
+		};
+		evaluator = new DefaultEvaluationStrategy(ts, null);
+	}
+
+	@Test
+	public void zeroHop() {
+		// SELECT * WHERE { ?subClass rdfs:subClassOf+ ?superClass }
+
+		Var startVar = new Var("subClass");
+		Var endVar = new Var("superClass");
+		TupleExpr pathExpression = new StatementPattern(startVar, new Var("lala", RDFS.SUBCLASSOF, true, true), endVar);
+		Var contextVar = null;
+		long minLength = 0;
+		BindingSet bindings = new QueryBindingSet();
+		// Expect but not necessary in this order
+		// one | one
+		// one | two
+		// one | three
+		// two | three
+		// two | two
+		// three | three
+
+		try (PathIteration zlp = new PathIteration(evaluator, Scope.DEFAULT_CONTEXTS, startVar,
+				pathExpression, endVar, contextVar, minLength, bindings)) {
+			assertExpected(zlp.getNextElement(), one, one);
+
+			assertExpected(zlp.getNextElement(), two, two);
+
+			assertExpected(zlp.getNextElement(), three, three);
+
+			assertExpected(zlp.getNextElement(), one, two);
+
+			assertExpected(zlp.getNextElement(), two, three);
+
+			assertExpected(zlp.getNextElement(), one, three);
+
+			assertNull(zlp.getNextElement());
+		}
+	}
+
+	void assertExpected(BindingSet result, Value subClass, Value superClass) {
+		assertNotNull(result);
+		assertTrue(result.hasBinding("subClass"), "path zlp evaluation should binding for subClass var");
+		assertEquals(subClass, result.getBinding("subClass").getValue());
+		assertTrue(result.hasBinding("superClass"), "path zlp evaluation should binding for superClass var");
+		assertEquals(superClass, result.getBinding("superClass").getValue());
+	}
+
+	@Test
+	public void oneHop() {
+		// SELECT * WHERE { ?subClass rdfs:subClassOf+ ?superClass }
+
+		Var startVar = new Var("subClass");
+		Var endVar = new Var("superClass");
+		TupleExpr pathExpression = new StatementPattern(startVar, new Var("lala", RDFS.SUBCLASSOF, true, true), endVar);
+		Var contextVar = null;
+		long minLength = 1;
+		// Expected
+		// one two
+		// one three
+		// two three
+		BindingSet bindings = new QueryBindingSet();
+		try (PathIteration zlp = new PathIteration(evaluator, Scope.DEFAULT_CONTEXTS, startVar,
+				pathExpression, endVar, contextVar, minLength, bindings)) {
+			assertExpected(zlp.getNextElement(), one, two);
+			assertExpected(zlp.getNextElement(), two, three);
+			assertExpected(zlp.getNextElement(), one, three);
+			assertNull(zlp.getNextElement());
+		}
+	}
+
+	@Test
+	public void oneHopStartConstant() {
+		// SELECT * WHERE { ?subClass rdfs:subClassOf+ ?superClass }
+
+		Var startVar = new Var("subClass", one, true, true);
+		Var endVar = new Var("superClass");
+		TupleExpr pathExpression = new StatementPattern(startVar, new Var("lala", RDFS.SUBCLASSOF, true, true), endVar);
+		Var contextVar = null;
+		long minLength = 1;
+		BindingSet bindings = new QueryBindingSet();
+		try (PathIteration zlp = new PathIteration(evaluator, Scope.DEFAULT_CONTEXTS, startVar,
+				pathExpression, endVar, contextVar, minLength, bindings)) {
+			assertExpected(zlp.getNextElement(), one, two);
+			assertExpected(zlp.getNextElement(), one, three);
+			assertNull(zlp.getNextElement());
+		}
+	}
+}