/*******************************************************************************
* Copyright (c) 2009-2013 CWI
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* * Wietse Venema - wietsevenema@gmail.com - CWI
* * Paul Klint - Paul.Klint@cwi.nl - CWI - added type parameters
*******************************************************************************/
package org.rascalmpl.library.cobra;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import org.rascalmpl.interpreter.IEvaluatorContext;
import org.rascalmpl.interpreter.control_exceptions.Throw;
import org.rascalmpl.interpreter.env.Environment;
import org.rascalmpl.interpreter.env.ModuleEnvironment;
import org.rascalmpl.interpreter.result.AbstractFunction;
import org.rascalmpl.interpreter.result.ICallableValue;
import org.rascalmpl.interpreter.types.FunctionType;
import org.rascalmpl.value.IBool;
import org.rascalmpl.value.IConstructor;
import org.rascalmpl.value.IString;
import org.rascalmpl.value.IValue;
import org.rascalmpl.value.IValueFactory;
import org.rascalmpl.value.type.Type;
public class QuickCheck {
private final String EXPECT_TAG = "expected";
private static class InstanceHolder {
public static final QuickCheck sInstance = new QuickCheck();
}
static final HashMap<Type, ICallableValue> generators = new HashMap<Type, ICallableValue>();
public static QuickCheck getInstance() {
return InstanceHolder.sInstance;
}
public IValue arbitrary(Type type, int depthLimit, Environment env,
IValueFactory vf, Map<Type, Type> typeParameters) {
RandomValueTypeVisitor visitor = new RandomValueTypeVisitor(vf,
(ModuleEnvironment) env, depthLimit, generators, typeParameters);
IValue result = visitor.generate(type);
if (result == null) {
throw new IllegalArgumentException("No construction possible at this depth or less.");
}
return result;
}
private boolean generatorExists(Type t) {
return generators.containsKey(t);
}
public IValue getGenerator(IValue t, IEvaluatorContext eval) {
Type reified = Cobra.reifyType(t);
if (generatorExists(reified)) {
return generators.get(reified);
}
return new DynamicGenerator(eval.getEvaluator(), reified,
eval.getCurrentEnvt(), generators);
}
public boolean quickcheck(AbstractFunction function, int maxDepth,
int tries, boolean verbose, PrintWriter out) {
String fname = function.getEnv().getName() + "::" + function.getName();
Environment declEnv = function.getEnv();
IValueFactory vf = function.getEval().getValueFactory();
Type formals = function.getFormals();
String expected = null;
if(function.hasTag(EXPECT_TAG)){
expected = ((IString) function.getTag(EXPECT_TAG)).getValue();
}
Type[] types = new Type[formals.getArity()];
IValue[] values = new IValue[formals.getArity()];
for (int n = 0; n < formals.getArity(); n++) {
types[n] = formals.getFieldType(n);
}
if (formals.getArity() == 0) {
tries = 1;
}
TypeParameterVisitor tpvisit = new TypeParameterVisitor();
for (int i = 0; i < tries; i++) {
values = new IValue[formals.getArity()];
HashMap<Type, Type> tpbindings = tpvisit.bindTypeParameters(formals);
for (int n = 0; n < formals.getArity(); n++) {
values[n] = arbitrary(types[n], maxDepth, declEnv.getRoot(), vf, tpbindings);
}
boolean expectedThrown = false;
try {
Type[] actualTypes = new Type[formals.getArity()];
for(int j = 0; j < types.length; j ++) {
actualTypes[j] = types[j].instantiate(tpbindings);
}
IValue result = function.call(actualTypes, values, null).getValue();
function.getEval().getStdOut().flush();
if (expected != null) {
// no exception at all is thrown
return reportMissingException(fname, expected, out);
}
if (!((IBool) result).getValue()) {
reportFailed(fname, "test returns false", tpbindings, formals, values, out);
return false;
} else if (verbose && formals.getArity() > 0) {
out.println((i + 1) + ": Checked with " + Arrays.toString(values) + ": true");
}
}
catch (Throw e) {
if(expected == null || !((IConstructor)e.getException()).getName().equals(expected)){
return reportFailed(fname, e.getMessage(), tpbindings, formals, values, out);
}
expectedThrown = true;
}
catch (Throwable e) {
e.printStackTrace();
if(expected == null || !e.getClass().toString().endsWith("." + expected)){
return reportFailed(fname, e.getMessage(), tpbindings, formals, values, out);
}
expectedThrown = true;
}
if(expected != null && !expectedThrown){
return reportMissingException(fname, expected, out);
}
}
out.println("Test " + fname + (formals.getArity() > 0 ? " not refuted after " + tries + " tries with maximum depth " + maxDepth
: " succeeded"));
return true;
}
private boolean reportFailed(String name, String msg, HashMap<Type, Type> tpbindings, Type formals, IValue[] values, PrintWriter out){
out.println("Test " + name + " failed due to\n\t" + msg + "\n");
if(tpbindings.size() > 0){
out.println("Type parameters:");
for(Type key : tpbindings.keySet()){
out.println("\t" + key + " => " + tpbindings.get(key));
}
}
out.println("Actual parameters:");
for (int i = 0; i < formals.getArity(); i++) {
IValue arg = values[i];
out.println("\t" + formals.getFieldType(i) + " " + "=>" + arg);
}
out.println();
return false;
}
private boolean reportMissingException(String name, String msg, PrintWriter out){
out.println("Test " + name + " failed due to\n\tmissing exception: " + msg + "\n");
return false;
}
public void resetGenerator(IValue type) {
Type reified = Cobra.reifyType(type);
generators.remove(reified);
}
public void setGenerator(IValue f) {
FunctionType functionType = (FunctionType) f.getType();
Type returnType = functionType.getReturnType();
ICallableValue generator = (ICallableValue) f;
generators.put(returnType, generator);
}
}