adding instructions about how to run the unit tests

Author: sergio-castro

src/test/java/org/jpc/examples/osm/OsmTestSuite.java

@@ -3,27 +3,42 @@
 import static org.jpc.engine.provider.PrologEngineProviderManager.setPrologEngine;
 
 import org.jpc.engine.prolog.PrologEngine;
-import org.jpc.engine.prolog.PrologEngines;
 import org.junit.BeforeClass;
 import org.junit.runner.RunWith;
 import org.junit.runners.Suite;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
+ * The tests in this test suite are commented out since in order to be executed a Prolog engine driver needs to be configured first.
+ * In order to execute the unit tests follow these instructions:
+ * - Uncomment the tests in the SuiteClasses annotation.
+ * - Initialize a prologEngine according to one of the driver configurations defined in the jpc.settings file (see examples commented out below).
+ * - Add a dependency in the POM to the selected driver (e.g., the artifact "jpc-jpl" for the jpl-based driver, or "jpc-drivers" for all the known jpc drivers). 
+ * To use other drivers than the jpl-based one, refer to the JPC installation guide.
+ * 
  * @author sergioc
- *
  */
 @RunWith(Suite.class)
-@Suite.SuiteClasses({OsmTest.class})
+@Suite.SuiteClasses({/*OsmTest.class*/})
 public class OsmTestSuite {
+	
+	public static final Logger logger = LoggerFactory.getLogger(OsmTestSuite.class);
+	
 	@BeforeClass
     public static void oneTimeSetUp() {
-		PrologEngine prologEngine = PrologEngines.getPrologEngineById("swi_jpl");
+		PrologEngine prologEngine = null;
+		//PrologEngine prologEngine = PrologEngines.getPrologEngineById("swi_jpl");
+		//PrologEngine prologEngine = PrologEngines.getPrologEngineById("yap_jpl");
 		//PrologEngine prologEngine = PrologEngines.getPrologEngineById("swi_pdt");
 		//PrologEngine prologEngine = PrologEngines.getPrologEngineById("xsb_interprolog");
-		setPrologEngine(prologEngine);
-		if(!MapQuery.loadAll()) //load logic files
-			throw new RuntimeException();
-		MapQuery.importData(); //import data to the logic database from text file
-		//prologEngine.query("map::load_osm(file('/Users/sergioc/Documents/workspaces/heal/mapquery/src/main/resources/org/jpc/examples/osm/brussels_center_filtered.osm'))").oneSolutionOrThrow();
+		if(prologEngine != null) {
+			setPrologEngine(prologEngine);
+			if(!MapQuery.loadAll()) //load logic files
+				throw new RuntimeException();
+			MapQuery.importData(); //import data to the logic database from text file
+			//prologEngine.query("map::load_osm(file('/Users/sergioc/Documents/workspaces/heal/mapquery/src/main/resources/org/jpc/examples/osm/brussels_center_filtered.osm'))").oneSolutionOrThrow();
+		} else
+			logger.warn("No JPC driver has been configured. Skipping tests.");
     }
 }