TestGregorMutater.java

/*
 * Copyright 2010 Henry Coles
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and limitations under the License.
 */
package org.pitest.mutationtest.engine.gregor;

import static org.hamcrest.core.Is.is;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertThat;
import static org.junit.Assert.assertTrue;

import java.util.Collection;
import java.util.List;

import org.hamcrest.Description;
import org.hamcrest.Matcher;
import org.hamcrest.TypeSafeMatcher;
import org.junit.Test;
import org.pitest.functional.F;
import org.pitest.functional.FCollection;
import org.pitest.functional.FunctionalList;
import org.pitest.functional.predicate.True;
import org.pitest.mutationtest.engine.MutationDetails;
import org.pitest.mutationtest.engine.gregor.config.Mutator;
import org.pitest.mutationtest.engine.gregor.mutators.IncrementsMutator;
import org.pitest.mutationtest.engine.gregor.mutators.InvertNegsMutator;
import org.pitest.mutationtest.engine.gregor.mutators.MathMutator;
import org.pitest.mutationtest.engine.gregor.mutators.ReturnValsMutator;
import org.pitest.util.ResourceFolderByteArraySource;

public class TestGregorMutater extends MutatorTestBase {

  public static class HasMultipleMutations {
    public int mutable() {
      int j = 10;
      for (int i = 0; i != 10; i++) {
        j = j << 1;
      }

      return -j;
    }

  }

  @Test
  public void shouldFindMutationsFromAllSuppliedMutators() throws Exception {

    createTesteeWith(MathMutator.MATH_MUTATOR,
        ReturnValsMutator.RETURN_VALS_MUTATOR,
        InvertNegsMutator.INVERT_NEGS_MUTATOR,
        IncrementsMutator.INCREMENTS_MUTATOR);

    final FunctionalList<MutationDetails> actualDetails = findMutationsFor(HasMultipleMutations.class);

    assertTrue(actualDetails
        .contains(descriptionContaining("Replaced Shift Left with Shift Right")));
    assertTrue(actualDetails
        .contains(descriptionContaining("replaced return of integer")));
    assertTrue(actualDetails
        .contains(descriptionContaining("Changed increment")));
    assertTrue(actualDetails
        .contains(descriptionContaining("removed negation")));

  }

  @Test
  public void shouldFindNoMutationsWhenNoMutationOperatorsSupplied()
      throws Exception {
    class VeryMutable {
      @SuppressWarnings("unused")
      public int f(final int i) {
        switch (i) {
        case 0:
          return 1;
        }
        return 0;
      }
    }
    createTesteeWith();
    final FunctionalList<MutationDetails> actualDetails = findMutationsFor(VeryMutable.class);
    assertTrue(actualDetails.isEmpty());

  }

  static enum AnEnum {
    Foo, Bar;
  }

  @Test
  public void shouldNotMutateCodeGeneratedByCompilerToImplementEnums() {
    createTesteeWith(Mutator.all());
    final Collection<MutationDetails> actualDetails = findMutationsFor(AnEnum.class);
    assertTrue(actualDetails.isEmpty());
  }

  static enum EnumWithCustomConstructor {
    Foo, Bar;

    int i;

    EnumWithCustomConstructor() {
      this.i++;
    }

  }

  @Test
  public void shouldMutateCustomConstructorsAddedToEnums() {
    createTesteeWith(Mutator.all());
    final Collection<MutationDetails> actualDetails = findMutationsFor(EnumWithCustomConstructor.class);
    assertThat(actualDetails, is(aNonEmptyCollection()));
  }

  private static Matcher<Collection<?>> aNonEmptyCollection() {
    return new TypeSafeMatcher<Collection<?>>() {

      @Override
      public void describeTo(final Description description) {
        description.appendText("a non empty collection");
      }

      @Override
      public boolean matchesSafely(final Collection<?> item) {
        return !item.isEmpty();
      }
    };
  }

  public static class HasAssertStatement {
    public void foo(final int i) {
      assert ((i + 20) > 10);
    }
  }

  @Test
  public void shouldNotMutateAssertStatments() {
    createTesteeWith(Mutator.byName("NEGATE_CONDITIONALS"));
    final Collection<MutationDetails> actualDetails = findMutationsFor(HasAssertStatement.class);
    assertEquals(0, actualDetails.size());
  }

  public static class HasAssertStatementAndOtherStatements {
    public int state;

    public void foo(final int i) {
      assert ((i + 20) > 10);
      if (i > 1) {
        this.state = 1;
      }
    }
  }

  @Test
  public void shouldMutateOtherStatementsWhenAssertIsPresent() {
    createTesteeWith(Mutator.byName("NEGATE_CONDITIONALS"));
    final Collection<MutationDetails> actualDetails = findMutationsFor(HasAssertStatementAndOtherStatements.class);
    assertEquals(1, actualDetails.size());
  }

  @Test
  public void shouldNotMutateGroovyClasses() {
    createTesteeWith(new ResourceFolderByteArraySource(),
        True.<MethodInfo> all(), Mutator.all());
    final Collection<MutationDetails> actualDetails = findMutationsFor("groovy/SomeGroovyCode");
    assertTrue(actualDetails.isEmpty());
  }

  @Test
  public void shouldNotMutateGroovyClosures() {
    createTesteeWith(new ResourceFolderByteArraySource(),
        True.<MethodInfo> all(), Mutator.all());
    final Collection<MutationDetails> actualDetails = findMutationsFor("groovy/SomeGroovyCode$_mapToString_closure2");
    assertTrue(actualDetails.isEmpty());
  }

  public static class OneStraightThroughMethod {
    public void straightThrough(int i) {
      i++;
      i++;
    }
  }

  @Test
  public void shouldRecordMutationsAsInSameBlockWhenForAStraightThroughMethod() {
    createTesteeWith(Mutator.byName("INCREMENTS"));
    final List<MutationDetails> actualDetails = findMutationsFor(OneStraightThroughMethod.class);
    assertEquals(2, actualDetails.size());
    final int firstMutationBlock = actualDetails.get(0).getBlock();
    assertEquals(firstMutationBlock, actualDetails.get(1).getBlock());
  }

  public static class SimpleBranch {
    public void straightThrough(int i, final boolean b) {
      if (b) {
        i++;
      } else {
        i++;
      }
    }
  }

  @Test
  public void shouldRecordMutationsAsInDifferentBlocksWhenInDifferentBranchesOfIfStatement() {
    createTesteeWith(Mutator.byName("INCREMENTS"));
    final List<MutationDetails> actualDetails = findMutationsFor(SimpleBranch.class);
    assertTwoMutationsInDifferentBlocks(actualDetails);
  }

  public static class TwoMethods {
    public void a(int i) {
      i++;
    }

    public void b(int i) {
      i++;
    }
  }

  @Test
  public void shouldRecordMutationsAsInDifferentBlocksWhenInDifferentMethods() {
    createTesteeWith(Mutator.byName("INCREMENTS"));
    final List<MutationDetails> actualDetails = findMutationsFor(TwoMethods.class);
    assertTwoMutationsInDifferentBlocks(actualDetails);
  }

  public static class SwitchStatement {
    public void a(int i, final int b) {
      switch (b) {
      case 0:
        i++;
        break;
      case 1:
        i++;
        break;
      default:
        i++;
      }
    }

  }

  @Test
  public void shouldRecordMutationsAsInDifferentBlocksWhenInDifferentBranchesOfSwitchStatement() {
    createTesteeWith(Mutator.byName("INCREMENTS"));
    final List<MutationDetails> actualDetails = findMutationsFor(SwitchStatement.class);
    assertEquals(3, actualDetails.size());
    final int firstMutationBlock = actualDetails.get(0).getBlock();
    assertEquals(firstMutationBlock + 1, actualDetails.get(1).getBlock());
    assertEquals(firstMutationBlock + 2, actualDetails.get(2).getBlock());
  }

  public static class FallThroughSwitch {
    public void a(int i, final int b) {
      switch (b) {
      case 0:
        i++;
      case 1:
        i++;
      }
    }
  }

  @Test
  public void shouldRecordMutationsAsInSameBlockWhenSwitchStatementFallsThrough() {
    createTesteeWith(Mutator.byName("INCREMENTS"));
    final List<MutationDetails> actualDetails = findMutationsFor(FallThroughSwitch.class);
    assertEquals(2, actualDetails.size());
    final int firstMutationBlock = actualDetails.get(0).getBlock();
    assertEquals(firstMutationBlock, actualDetails.get(1).getBlock());
  }

  public static class HasExceptionBlock {
    public void foo(int i) {
      try {
        i++;
      } catch (final Exception ex) {
        i++;
      }
    }
  }

  @Test
  public void shouldRecordMutationsAsInDifferentBlocksWhenInExceptionHandler() {
    createTesteeWith(Mutator.byName("INCREMENTS"));
    final List<MutationDetails> actualDetails = findMutationsFor(HasExceptionBlock.class);
    assertTwoMutationsInDifferentBlocks(actualDetails);
  }

  @Test
  public void shouldNotRecordMutationsAsInFinallyBlockWhenTheyAreNot() {
    createTesteeWith(Mutator.byName("INCREMENTS"));
    final List<MutationDetails> actualDetails = findMutationsFor(HasExceptionBlock.class);
    assertFalse(actualDetails.get(0).isInFinallyBlock());
    assertFalse(actualDetails.get(1).isInFinallyBlock());
  }

  public static class HasFinallyBlock {
    public void foo(int i) {
      try {
        System.out.println("foo");
      } finally {
        i++;
      }
    }
  }

  @Test
  public void shouldMarkMutationsWithinFinallyBlocks() {
    createTesteeWith(Mutator.byName("INCREMENTS"));
    final List<MutationDetails> actualDetails = findMutationsFor(HasFinallyBlock.class);
    assertEquals(1, FCollection.filter(actualDetails, isInFinallyBlock())
        .size());
  }

  public static class HasFinallyBlockAndExceptionHandler {
    public void foo(int i) {
      try {
        System.out.println("foo");
      } catch (final Exception x) {
        System.out.println("bar");
      } finally {
        i++;
      }
    }
  }

  @Test
  public void shouldMarkMutationsWithinFinallyBlocksWhenExceptionHandlerAlsoPresent() {
    createTesteeWith(Mutator.byName("INCREMENTS"));
    final List<MutationDetails> actualDetails = findMutationsFor(HasFinallyBlockAndExceptionHandler.class);
    assertEquals(1, FCollection.filter(actualDetails, isInFinallyBlock())
        .size());
  }

  public static class HasTwoMutableMethods {
    public int a() {
      return 1;
    }

    public int a(int i) {
      if (i > 2) {
        System.out.println(i);
      }
      return 1;
    }
  }

  @Test
  public void shouldScopeMutationIndexesByInstructionCounter() {
    createTesteeWith(Mutator.byName("RETURN_VALS"));
    final List<MutationDetails> actualDetails = findMutationsFor(HasTwoMutableMethods.class);
    assertEquals(2, actualDetails.size());
    assertEquals(4, actualDetails.get(0).getId().getFirstIndex());
    assertEquals(15, actualDetails.get(1).getId().getFirstIndex()); // differs
                                                                    // by
                                                                    // target?
  }


  
  @Test
  public void shouldNotMutateMethodsAnnotatedWithGenerated() {
    createTesteeWith(Mutator.byName("RETURN_VALS"));
    final List<MutationDetails> actualDetails = findMutationsFor(AnnotatedToAvoidMethod.class);
    // all but two methods are annotated to ignore
    assertEquals(2, actualDetails.size());
  }
  
  public static class AnnotatedToAvoidMethod {
    public int a() {
      return 1;
    }

    @Generated
    public int b() {
      return 1;
    }
    
    @DoNotMutate
    public int c() {
      return 1;
    }
    
    @CoverageIgnore
    public int d() {
      return 1;
    }
    
    public int e() {
      return 1;
    }
  }
  
  
  private static F<MutationDetails, Boolean> isInFinallyBlock() {
    return new F<MutationDetails, Boolean>() {
      @Override
      public Boolean apply(final MutationDetails a) {
        return a.isInFinallyBlock();
      }

    };
  }

  private void assertTwoMutationsInDifferentBlocks(
      final List<MutationDetails> actualDetails) {
    assertEquals(2, actualDetails.size());
    final int firstMutationBlock = actualDetails.get(0).getBlock();
    assertEquals(firstMutationBlock + 1, actualDetails.get(1).getBlock());
  }
}