code: /*
   * Copyright (c) 2017-2018 The Regents of the University of California
   * Copyright (c) 2020-2021 Rohan Padhye
   *
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   *
   * 1. Redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   * notice, this list of conditions and the following disclaimer in the
   * documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  package edu.berkeley.cs.jqf.fuzz;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Random;
  
  import com.pholser.junit.quickcheck.Property;
  import com.pholser.junit.quickcheck.internal.generator.GeneratorRepository;
  import com.pholser.junit.quickcheck.internal.generator.ServiceLoaderGeneratorSource;
  import com.pholser.junit.quickcheck.random.SourceOfRandomness;
  import com.pholser.junit.quickcheck.runner.JUnitQuickcheck;
  import edu.berkeley.cs.jqf.fuzz.difffuzz.Comparison;
  import edu.berkeley.cs.jqf.fuzz.difffuzz.DiffFuzz;
  import edu.berkeley.cs.jqf.fuzz.difffuzz.DiffFuzzGuidance;
  import edu.berkeley.cs.jqf.fuzz.difffuzz.DiffFuzzNoGuidance;
  import edu.berkeley.cs.jqf.fuzz.guidance.Guidance;
  import edu.berkeley.cs.jqf.fuzz.guidance.GuidanceException;
  import edu.berkeley.cs.jqf.fuzz.junit.GuidedFuzzing;
  import edu.berkeley.cs.jqf.fuzz.junit.quickcheck.FuzzStatement;
  import edu.berkeley.cs.jqf.fuzz.random.NoGuidance;
  import edu.berkeley.cs.jqf.fuzz.repro.ReproGuidance;
  import org.junit.runners.model.FrameworkMethod;
  import org.junit.runners.model.InitializationError;
  import org.junit.runners.model.Statement;
  
  /**
   * This class extends JUnit and Quickcheck runners to enable guided
   * fuzz testing. 
   *
   * @author Rohan Padhye
   */
  public class JQF extends JUnitQuickcheck {
  
      protected final GeneratorRepository generatorRepository;
  
      Map<String, FrameworkMethod> cmpNames;
  
      @SuppressWarnings("unused") // Invoked reflectively by JUnit
      public JQF(Class<?> clazz) throws InitializationError {
          super(clazz);
          // Initialize generator repository with a deterministic seed (for reproducibility)
          SourceOfRandomness randomness = new SourceOfRandomness(new Random(42));
          this.generatorRepository = new GeneratorRepository(randomness).register(new ServiceLoaderGeneratorSource());
      }
  
      @Override protected List<FrameworkMethod> computeTestMethods() {
          List<FrameworkMethod> methods = super.computeTestMethods();
          methods.addAll(getTestClass().getAnnotatedMethods(Fuzz.class));
          methods.addAll(getTestClass().getAnnotatedMethods(DiffFuzz.class));
          return methods;
      }
  
  
      @Override protected void validateTestMethods(List<Throwable> errors) {
          super.validateTestMethods(errors);
          validateFuzzMethods(errors);
          cmpNames = new HashMap<>();
          validateComparisonMethods(errors);
          validateRegressionMethods(errors);
      }
  
      private void validateFuzzMethods(List<Throwable> errors) {
          for (FrameworkMethod method : getTestClass().getAnnotatedMethods(Fuzz.class)) {
              method.validatePublicVoid(false, errors);
              if (method.getAnnotation(Property.class) != null) {
                  errors.add(new Exception("Method " + method.getName() +
                          " cannot have both @Property and @Fuzz annotations"));
              }
          }
      }
  
      private void validateComparisonMethods(List<Throwable> errors) {
          for(FrameworkMethod method : getTestClass().getAnnotatedMethods(Comparison.class)) {
              if(method.getReturnType() != Boolean.class) {
                  errors.add(new Exception("Method " + method.getName() + " must return Boolean"));
              }
              Class<?>[] parameters = method.getMethod().getParameterTypes();
              if(parameters.length != 2 || parameters[0] != parameters[1]) {
                  errors.add(new Exception("Method " + method.getName()
                          + " must have exactly two parameters, and they must be of the same type"));
              }
              cmpNames.put(method.getName(), method);
          }
      }
  
      private void validateRegressionMethods(List<Throwable> errors) {
          for(FrameworkMethod method : getTestClass().getAnnotatedMethods(DiffFuzz.class)) {
              if(method.getReturnType() == null) {
                  errors.add(new Exception("Method " + method.getName() + " cannot be void"));
              }
              if(!method.isPublic()) {
                  errors.add(new Exception("Method " + method.getName() + " must be public"));
              }
              if(method.isStatic()) {
                  errors.add(new Exception("Method " + method.getName() + " must not be static"));
              }
  
              String cmp = method.getAnnotation(DiffFuzz.class).cmp();
              if(!cmp.equals("") && !cmpNames.containsKey(cmp)) {
                  errors.add(new Exception("cmp() in Diff annotation of method " + method.getName()
                          + " must be the name of a function in this class marked with the @Comparison annotation"));
              } else if(!cmp.equals("") && cmpNames.get(cmp).getMethod().getParameterTypes()[0] != method.getReturnType()) {
                  errors.add(new Exception("The function referred to by cmp() in Regression annotation of method "
                          + method + " must accept arguments matching the return type of the method"));
              }
          }
      }
  
      @Override public Statement methodBlock(FrameworkMethod method) {
          // JQF needs special handling for @Fuzz or @DiffFuzz test methods
          if (method.getAnnotation(Fuzz.class) != null) {
              // Get currently set fuzzing guidance
              Guidance guidance = GuidedFuzzing.getCurrentGuidance();
  
              // If nothing is set, default to random or repro
              if (guidance == null) {
                  // Check for @Fuzz(repro=)
                  String repro = method.getAnnotation(Fuzz.class).repro();
                  if (repro.isEmpty()) {
                      long maxTrials = Long.getLong("jqf.quickcheck.trials", GuidedFuzzing.DEFAULT_MAX_TRIALS);
                      guidance = new NoGuidance(maxTrials, System.err);
                  } else {
                      String reproPath;
                      // Check if repro path is variable (e.g. `${foo}`)
                      if (repro.matches("\\$\\{[a-zA-Z.\\d_$]*\\}")) {
                          // Get a system property with that name (e.g. `foo`)
                          String key = repro.substring(2, repro.length() - 1);
                          String val = System.getProperty(key);
  
                          // Check if such a property is set
                          if (val == null) {
                              throw new IllegalArgumentException(String.format("Test method has " +
                                              "@Fuzz annotation with repro=%s, but such a system " +
                                              "property is not set. Use `-D%s=<path>` when running.",
                                      repro, key));
                          }
  
                          reproPath = val;
                      } else {
                          // If it is not a variable, then treat it literally
                          reproPath = repro;
                      }
  
                      // Create a ReproGuidance with the given path
                      File inputFile = new File(reproPath);
                      try {
                          guidance = new ReproGuidance(inputFile, null);
                      } catch (IOException e) {
                          throw new GuidanceException(String.format("Could not open repro file: %s",
                                  inputFile.getAbsolutePath()), e);
                      }
                  }
              }
  
              return new FuzzStatement(method, getTestClass(), generatorRepository, guidance);
  
          } else if (method.getAnnotation(DiffFuzz.class) != null) {
              // Get currently set fuzzing guidance
              Guidance guidance = GuidedFuzzing.getCurrentGuidance();
              DiffFuzzGuidance diffGuidance;
  
              if (guidance == null) {
                  guidance = new DiffFuzzNoGuidance(GuidedFuzzing.DEFAULT_MAX_TRIALS, System.err);
              }
  
              if (!(guidance instanceof DiffFuzzGuidance)) {
                  throw new IllegalStateException("@DiffFuzz methods cannot be fuzzed with a " +
                          guidance.getClass().getName());
              }
              diffGuidance = (DiffFuzzGuidance) guidance;
  
              if (method.getAnnotation(DiffFuzz.class).cmp().isEmpty() == false) {
                  diffGuidance.setCompare(cmpNames.get(method.getAnnotation(DiffFuzz.class).cmp()).getMethod());
              }
  
              return new FuzzStatement(method, getTestClass(), generatorRepository, diffGuidance);
          } else {
              return super.methodBlock(method);
          }
      }
  }
  