Defects4J -- version 2.0.0

Defects4J is a collection of reproducible bugs and a supporting infrastructure with the goal of advancing software engineering research.

Contents of Defects4J

The projects

Defects4J contains 438 bugs from the following open-source projects:

Identifier	Project name	Number of bugs
Chart	JFreeChart	26
Closure	Closure compiler	176
Lang	Apache commons-lang	65
Math	Apache commons-math	106
Mockito	Mockito	38
Time	Joda-Time	27

The bugs

Each bug has the following properties:

• Issue filed in the corresponding issue tracker, and issue tracker identifier mentioned in the fixing commit message.
• Fixed in a single commit
• Minimized: the Defects4J maintainers manually pruned out irrelevant changes in the commit (e.g., refactorings or feature additions).
• Fixed by modifying the source code (as opposed to configuration files, documentation, or test files).
• A triggering test exists that failed before the fix and passes after the fix -- the test failure is not random or dependent on test execution order.

The (b)uggy and (f)ixed program revisions are labelled with <id>b and <id>f, respectively (<id> is an integer).

Setting up Defects4J

Requirements

• Java 1.7
• Git >= 1.9
• SVN >= 1.8
• Perl >= 5.0.10

Java version

All bugs have been reproduced and triggering tests verified, using the latest version of Java 1.7. Note that using Java 1.8+ might result in unexpected failing tests on a fixed program version. The next major release of Defects4J will be compatible with Java 8.

Perl dependencies

All required Perl modules are listed in cpanfile. On many Unix platforms, these required Perl modules are installed by default. If this is not the case, you can use cpan (or a cpan wrapper) to install them. For example, if you have cpanm installed, you can automatically install all modules by running: cpanm --installdeps .

Timezone

Defects4J generates and executes tests in the timezone America/Los_Angeles. If you are using the bugs outside of the Defects4J framework, set the TZ environment variable to America/Los_Angeles and export it.

Steps to set up Defects4J

1. Clone Defects4J:

   • git clone https://github.com/rjust/defects4j

2. Initialize Defects4J (download the project repositories and external libraries, which are not included in the git repository for size purposes and to avoid redundancies):

   • cd defects4j
   • ./init.sh

3. Add Defects4J's executables to your PATH:

   • export PATH=$PATH:"path2defects4j"/framework/bin

4. Check installation:

   • defects4j info -p Lang

Using Defects4J

Example commands

1. Get information for a specific project (commons lang):

   • defects4j info -p Lang

2. Get information for a specific bug (commons lang, bug 1):

   • defects4j info -p Lang -b 1

3. Checkout a buggy source code version (commons lang, bug 1, buggy version):

   • defects4j checkout -p Lang -v 1b -w /tmp/lang_1_buggy

4. Change to the working directory, compile sources and tests, and run tests:

   • cd /tmp/lang_1_buggy
   • defects4j compile
   • defects4j test

5. The scripts in framework/test/ are examples of how to use Defects4J, which you might find useful as inspiration when you are writing your own scripts that use Defects4J.

Command-line interface: defects4j command

Use framework/bin/defects4j to execute any of the following commands:

Command	Description
info	View configuration of a specific project or summary of a specific bug
checkout	Checkout a buggy or a fixed project version
compile	Compile sources and developer-written tests of a buggy or a fixed project version
test	Run a single test method or a test suite on a buggy or a fixed project version
mutation	Run mutation analysis on a buggy or a fixed project version
coverage	Run code coverage analysis on a buggy or a fixed project version
monitor.test	Monitor the class loader during the execution of a single test or a test suite
export	Export version-specific properties such as classpaths, directories, or lists of tests

Export version-specific properties

Use defects4j export -p <property_name> [-o output_file] in the working directory to export a version-specific property:

Property	Description
classes.modified	Classes (source files) modified by the bug fix
cp.compile	Classpath to compile and run the project
cp.test	Classpath to compile and run the developer-written tests
dir.src.classes	Source directory of classes (relative to working directory)
dir.bin.classes	Target directory of classes (relative to working directory)
dir.src.tests	Source directory of tests (relative to working directory)
dir.bin.tests	Target directory of test classes (relative to working directory)
tests.all	List of all developer-written test classes
tests.relevant	List of relevant tests classes (a test class is relevant if, when executed, the JVM loads at least one of the modified classes)
tests.trigger	List of test methods that trigger (expose) the bug

Test execution framework

The test execution framework for generated test suites (framework/bin) provides the following scripts:

Script	Description
defects4j	Main script, described above
run_bug_detection	Determine the real fault detection rate
run_mutation	Determine the mutation score
run_coverage	Determine code coverage ratios (statement and branch coverage)
run_evosuite	Generate test suites using EvoSuite
run_randoop	Generate test suites using Randoop

Mining and contributing additional bugs to Defects4J

The bug-mining README details the bug-mining process.

Additional resources

Scripts built on Defects4J

Fault localization (FL)

• Scripts and annotations for evaluating FL techniques

Automated program repair (APR)

• Scripts and annotations for evaluating APR techniques
• Patches generated with the Nopol, jGenProg, and jKali APR systems
• Repair actions and patterns for Defects4J v1.2.0

Publications

• "Defects4J: A Database of Existing Faults to Enable Controlled Testing Studies for Java Programs" René Just, Darioush Jalali, and Michael D. Ernst, ISSTA 2014 [download].

• "Are Mutants a Valid Substitute for Real Faults in Software Testing?" René Just, Darioush Jalali, Laura Inozemtseva, Michael D. Ernst, Reid Holmes, and Gordon Fraser, FSE 2014 [download].

More publications

Implementation details

Documentation for any script or module is available as html documentation.

The directory structure of Defects4J is as follows:

defects4j
   |
   |--- project_repos:     The version control repositories of the provided projects.
   |
   |--- major:             The Major mutation framework.
   |
   |--- framework:         Libraries and executables of the database abstraction and
       |                   test execution framework.
       |
       |--- bin:           Command line interface to Defects4J.
       |
       |--- core:          The modules of the core framework.
       |
       |--- lib:           Libraries used in the core framework.
       |
       |--- util:          Util scripts used by Defects4J.
       |
       |--- projects:      Project-specific resource files.
       |
       |--- test:          Scripts to test the framework.

Versioning information

Defects4J uses a semantic versioning scheme (major.minor.patch):

Change	major	minor	patch
Addition/Deletion of bugs	X
New/upgraded internal or external tools		X
Fixes and documentation changes			X

License

MIT License, see license.txt for more information.