Program: 28
Project: 28
Buggy source:
@Override public TestDefinition initialiseWikiMock(String filename) throws Exception {
  super.initialiseWikiMock(filename);
  when(xWikiBridge.getMainWikiReference()).thenReturn(testDefinition.getMainWiki().getWikiReference());
  when(xWikiBridge.isWikiReadOnly()).thenReturn(false);
  when(userBridge.getAllGroupsFor(any(UserSecurityReference.class),any(WikiReference.class))).thenAnswer(new Answer<Collection<GroupSecurityReference>>(){
    @Override public Collection<GroupSecurityReference> answer(    InvocationOnMock invocationOnMock) throws Throwable {
      UserSecurityReference userReference=(UserSecurityReference)invocationOnMock.getArguments()[0];
      WikiReference wikiReference=(WikiReference)invocationOnMock.getArguments()[1];
      if (userReference.getOriginalReference() == null) {
        return Collections.emptyList();
      }
      TestWiki wiki=testDefinition.getWiki(userReference.getOriginalReference().getWikiReference());
      if (wiki == null) {
        throw new AuthorizationException(String.format("String_Node_Str",userReference,wikiReference),null);
      }
      TestUserDocument user=wiki.getUser(userReference.getName());
      if (user == null) {
        return Collections.emptyList();
      }
      Collection<GroupSecurityReference> groups=new ArrayList<GroupSecurityReference>();
      for (      TestGroup group : user.getGroups()) {
        if (group.getGroupReference().getWikiReference().equals(wikiReference)) {
          groups.add(securityReferenceFactory.newGroupReference(group.getGroupReference()));
        }
      }
      return groups;
    }
  }
);
  when(securityEntryReader.read(any(SecurityReference.class))).thenAnswer(new Answer<SecurityRuleEntry>(){
    @Override public SecurityRuleEntry answer(    InvocationOnMock invocationOnMock) throws Throwable {
      final SecurityReference reference=(SecurityReference)invocationOnMock.getArguments()[0];
      TestEntity entity=testDefinition.searchEntity(reference);
      Collection<TestAccessRule> rules=(entity != null && entity instanceof SecureTestEntity) ? ((SecureTestEntity)entity).getAccessRules() : Collections.<TestAccessRule>emptyList();
      final Collection<SecurityRule> mockedRules=new ArrayList<SecurityRule>();
      for (      final TestAccessRule rule : rules) {
        mockedRules.add(mockSecurityRule(reference,rule.getRight(),rule.getState(),rule.getUser(),rule.isUser()));
      }
      if (entity instanceof TestWiki) {
        TestWiki wiki=(TestWiki)entity;
        if (wiki.getOwner() != null) {
          mockedRules.add(mockSecurityRule(reference,Right.ADMIN,RuleState.ALLOW,wiki.getOwner(),true));
        }
      }
      if (entity instanceof TestDocument) {
        TestDocument document=(TestDocument)entity;
        if (document.getCreator() != null) {
          mockedRules.add(mockSecurityRule(reference,Right.CREATOR,RuleState.ALLOW,document.getCreator(),true));
        }
      }
      SecurityRuleEntry accessEntry=mock(SecurityRuleEntry.class,String.format("String_Node_Str",reference.toString(),mockedRules.size()));
      when(accessEntry.getReference()).thenReturn(reference);
      when(accessEntry.isEmpty()).thenReturn(mockedRules.isEmpty());
      when(accessEntry.getRules()).thenReturn(mockedRules);
      return accessEntry;
    }
  }
);
  return testDefinition;
}

Fixed version (ground truth):
@Override public TestDefinition initialiseWikiMock(String filename) throws Exception {
  super.initialiseWikiMock(filename);
  when(xWikiBridge.getMainWikiReference()).thenReturn(testDefinition.getMainWiki().getWikiReference());
  when(xWikiBridge.isWikiReadOnly()).thenReturn(false);
  when(userBridge.getAllGroupsFor(any(UserSecurityReference.class),any(WikiReference.class))).thenAnswer(new Answer<Collection<GroupSecurityReference>>(){
    @Override public Collection<GroupSecurityReference> answer(    InvocationOnMock invocationOnMock) throws Throwable {
      UserSecurityReference userReference=(UserSecurityReference)invocationOnMock.getArguments()[0];
      WikiReference wikiReference=(WikiReference)invocationOnMock.getArguments()[1];
      if (userReference.getOriginalReference() == null) {
        return Collections.emptyList();
      }
      TestWiki wiki=testDefinition.getWiki(userReference.getOriginalReference().getWikiReference());
      if (wiki == null) {
        throw new AuthorizationException(String.format("String_Node_Str",userReference,wikiReference),null);
      }
      TestUserDocument user=wiki.getUser(userReference.getName());
      if (user == null) {
        return Collections.emptyList();
      }
      Collection<GroupSecurityReference> groups=new ArrayList<GroupSecurityReference>();
      for (      TestGroup group : user.getGroups()) {
        if (group.getGroupReference().getWikiReference().equals(wikiReference)) {
          groups.add(securityReferenceFactory.newGroupReference(group.getGroupReference()));
        }
      }
      return groups;
    }
  }
);
  when(securityEntryReader.read(any(SecurityReference.class))).thenAnswer(new Answer<SecurityRuleEntry>(){
    @Override public SecurityRuleEntry answer(    InvocationOnMock invocationOnMock) throws Throwable {
      final SecurityReference reference=(SecurityReference)invocationOnMock.getArguments()[0];
      TestEntity entity=testDefinition.searchEntity(reference);
      Collection<TestAccessRule> rules=(entity != null && entity instanceof SecureTestEntity) ? ((SecureTestEntity)entity).getAccessRules() : Collections.<TestAccessRule>emptyList();
      final Collection<SecurityRule> mockedRules=new ArrayList<SecurityRule>();
      for (      final TestAccessRule rule : rules) {
        mockedRules.add(mockSecurityRule(reference,rule.getRight(),rule.getState(),rule.getUser(),rule.isUser()));
      }
      if (entity instanceof TestWiki) {
        TestWiki wiki=(TestWiki)entity;
        if (wiki.getOwner() != null) {
          mockedRules.add(mockSecurityRule(reference,Right.ADMIN,RuleState.ALLOW,wiki.getOwner(),true));
        }
      }
      if (entity instanceof TestDocument) {
        TestDocument document=(TestDocument)entity;
        if (document.getCreator() != null) {
          mockedRules.add(mockSecurityRule(reference,Right.CREATOR,RuleState.ALLOW,document.getCreator(),true));
        }
      }
      return new AbstractSecurityRuleEntry(){
        @Override public Collection<SecurityRule> getRules(){
          return mockedRules;
        }
        @Override public SecurityReference getReference(){
          return reference;
        }
        public String toString(){
          return String.format("String_Node_Str",reference.toString(),mockedRules.size());
        }
        @Override public boolean equals(        Object object){
          if (object == this) {
            return true;
          }
          if (!(object instanceof SecurityRuleEntry)) {
            return false;
          }
          SecurityRuleEntry other=(SecurityRuleEntry)object;
          return compareReferenceNullSafe(other.getReference(),reference) && other.getRules().size() == mockedRules.size();
        }
      }
;
    }
  }
);
  return testDefinition;
}