svn commit: r1509776 - /jena/trunk/jena-arq/src/test/java/com/hp/hpl/jena/sparql/api/TestAPI.java

[rv...@apache.org]

Author: rvesse
Date: Fri Aug  2 16:58:31 2013
New Revision: 1509776

URL: http://svn.apache.org/r1509776
Log:
Test case which demonstrates that initial bindings and the optimizer can have strange interactions.  Users can write semantically always null queries which return information when initial bindings are used but the optimizer which knows nothing of initial bindings can make assumptions that a query is always null and diverge from user expectations

Modified:
    jena/trunk/jena-arq/src/test/java/com/hp/hpl/jena/sparql/api/TestAPI.java

Modified: jena/trunk/jena-arq/src/test/java/com/hp/hpl/jena/sparql/api/TestAPI.java
URL: http://svn.apache.org/viewvc/jena/trunk/jena-arq/src/test/java/com/hp/hpl/jena/sparql/api/TestAPI.java?rev=1509776&r1=1509775&r2=1509776&view=diff
==============================================================================
--- jena/trunk/jena-arq/src/test/java/com/hp/hpl/jena/sparql/api/TestAPI.java (original)
+++ jena/trunk/jena-arq/src/test/java/com/hp/hpl/jena/sparql/api/TestAPI.java Fri Aug  2 16:58:31 2013
@@ -21,6 +21,7 @@ package com.hp.hpl.jena.sparql.api;
 import java.util.Iterator;
 
 import org.apache.jena.atlas.junit.BaseTest ;
+import org.junit.Assert;
 import org.junit.Test ;
 
 import com.hp.hpl.jena.graph.Triple;
@@ -34,10 +35,14 @@ import com.hp.hpl.jena.query.ResultSet ;
 import com.hp.hpl.jena.query.ResultSetFormatter ;
 import com.hp.hpl.jena.query.Syntax ;
 import com.hp.hpl.jena.rdf.model.Model ;
+import com.hp.hpl.jena.rdf.model.ModelFactory;
 import com.hp.hpl.jena.rdf.model.Property ;
 import com.hp.hpl.jena.rdf.model.Resource ;
+import com.hp.hpl.jena.rdf.model.ResourceFactory;
+import com.hp.hpl.jena.sparql.algebra.Algebra;
 import com.hp.hpl.jena.sparql.graph.GraphFactory ;
 import com.hp.hpl.jena.vocabulary.OWL ;
+import com.hp.hpl.jena.vocabulary.RDF;
 
 public class TestAPI extends BaseTest
 {
@@ -172,6 +177,61 @@ public class TestAPI extends BaseTest
         qexec.close() ;
     }
     
+    /**
+     * This test demonstrates a disconnect between user understanding of 
+     * initial bindings and the reality of their implementation.
+     * <p>
+     * Using initial bindings can potentially change the semantics of the query 
+     * in unexpected ways such as making an always false query return true
+     * but sometimes the optimizer (which knows nothing of initial bindings)
+     * makes a decision which negates that potential.
+     * </p>
+     */
+    @Test public void testInitialBindings5() {
+        Query query = QueryFactory.create(
+                "ASK\n" +
+                "WHERE {\n" +
+                "    FILTER (?a = <http://constant>) .\n" +
+                "}");
+        //System.out.println(Algebra.optimize(Algebra.compile(query)).toString());
+        
+        Model model = ModelFactory.createDefaultModel();
+        model.add(OWL.Thing, RDF.type, OWL.Class);
+        QuerySolutionMap initialBinding = new QuerySolutionMap();
+        initialBinding.add("a", ResourceFactory.createResource("http://constant"));
+        QueryExecution qexec = QueryExecutionFactory.create(query, model, initialBinding);
+        boolean result = qexec.execAsk();
+        Assert.assertFalse(result);
+    }
+    
+    /**
+     * This test demonstrates a disconnect between user understanding of 
+     * initial bindings and the reality of their implementation.
+     * <p>
+     * Using initial bindings can potentially change the semantics of the query 
+     * in unexpected ways such as making an always false query return true
+     * but sometimes the optimizer (which knows nothing of initial bindings)
+     * makes a decision which negates that potential.
+     * </p>
+     */
+    @Test public void testInitialBindings6() {
+        Query query = QueryFactory.create(
+                "ASK\n" +
+                "WHERE {\n" +
+                "    FILTER (?a = ?b) .\n" +
+                "}");
+        //System.out.println(Algebra.optimize(Algebra.compile(query)).toString());
+        
+        Model model = ModelFactory.createDefaultModel();
+        model.add(OWL.Thing, RDF.type, OWL.Class);
+        QuerySolutionMap initialBinding = new QuerySolutionMap();
+        initialBinding.add("a", ResourceFactory.createTypedLiteral(Boolean.TRUE));
+        initialBinding.add("b", ResourceFactory.createTypedLiteral(Boolean.TRUE));
+        QueryExecution qexec = QueryExecutionFactory.create(query, model, initialBinding);
+        boolean result = qexec.execAsk();
+        Assert.assertFalse(result);
+    }
+    
     @Test public void testReuseQueryObject1()
     {
         String queryString = "SELECT * {?s ?p ?o}";