Add Unit Testing to Dspace - Pere Villega

Dspace currently lacks unit testing, which harms the development of the platform and makes easier to reintroduce past bugs while developing. This project is a proposal to add a set of unit test classes to Dspace, based on JUnit, plus some tools that detect issues in the code so we can improve its quality. - Pere Villega

On Testing

Due to the extension of the subject a new page has been created with more details. Please check [Testing] for more information on unit testing

Existing approaches

So far there's been some approaches to the problem. As far as we know, the following:

• Elliot Metsger created some unit testing framework as shown athttp://presentations.dlpe.gatech.edu/proed/or09/or09_052009_4/index.html
• Scott Phillips did a set of functional tests for DSpace 1.5 as seen athttp://scott.phillips.name/2010/04/dspace-functional-tests/
• Gareth Waller has built a set of Selenium tests as commented recently in the developer's list
• Aaron Zeckoski's effort added JUnit-based testing into DSpace Services e.g. http://scm.dspace.org/svn/repo/modules/dspace-services/tags/dspace-services-2.0.1/impl/src/test/java/org/dspace/test/DSpaceAbstractKernelTest.java

Next there is a table that compares these and some other approaches to the problem:

As we see we have two main approaches:

• Unit testing: automated, suffers from tight integration with database. Refactoring of code would be advisable, but it can be avoided by using Mocks. Tests at low level, just ensuring a class is correct, not checking the whole functionality. Can allow performance testing via ContiPerf.

• Functional testing: doesn't suffer from database integration. Ensure the functionality works, but it may not account for certain situations that would raise errors due to code bugs.

Both would benefit DSpace, as unit testing would ensure code quality while functional testing would ensure the application behaves as expected with standard usage.

Proposals

The proposals for the project are:

• Create a framework for Functional Tests, Integration Tests, Unit Tests and Performance Tests that run automatically on build (when possible)
  • I will create all the background require (mockups, database connections, configs, etc) for the tests to be run
  • I will integrate Cobertura to create reports on the testing coverage

• Integrate with a Continuous Integration server
• (Optional but recommended) Integrate with a code quality management tool

Scope

The main scope of the project is to apply the proposals to the API core. Once done, work would be extended in the remaining time to Manakin and then other subprojects (Sword, LNI, OIA). JSPUI will be left for last, as is an interface that will disappear in the future.

Considerations

DSpace code suffers from testability issues. In the long term it might be advisable to refactor it. Refactoring is dangerous right now as we don't have any test and we risk introducing new bugs to the code base, so it should be avoided until we have enough tests working that makes us confidant we can take that road.

Project Description

At first three basic objects will be created: an Abstract Functional Test, an Abstract Integration Test, and if needed an Abstract Unit Tests. These basic abstract tests would be able to preform the basic setup and teardown operations to get those resources needed: database, etc. The structure will include an embedded webserver, database and temporary file system.

Performance Testing will be achieved through the use of ContiPerf, a tool that reuses JUnit tests as performance tests.

Project Plan

A work plan has been decided in an IRC meeting on May 26th, 2010. The work has been divided in 3 parts:

1. Single class Unit Tests. Ideal candidates would be classes such a DCDate. These can be easily tested in isolation. This sort of test, along with an appropriate way for maven to execute them will give the project, and DSpace, and early win. Hopefully it will encourage further tests to be created by other developers, and we could move towards an expectation of new code requiring tests like this before they are committed.
2. Integration Testing, which requires a database to be present. This would ideally work with an embedded database such as hqsql or derby. We need to think about this a little more to decide how best to do this, and how it would interact with the new services architecture.
3. Functional Testing using a tool such as selenium.

It's been decided they will be done in the same order. The aim is not to do tests for all the existing classes, but to create an infrastructure the community can benefit from and can expand with its own tests.

The first task, ongoing until 13th/20th of June will be to add Unit Tests (#1) to package org.dspace.content.* . This part doesn't require any database integration and will use JUnit and JMock/Mockito as tools.

Technical description

A tecnical description of the tools used and steps followed is available at GSOC 2010 Unit Tests - Technical documentation

Source Code

The code is held in an SVN branch: http://scm.dspace.org/svn/repo/sandbox/gsoc/2010/testing/

Relevant Dates

The following list outlines relevant dates for the project:

• 26th May: 1st meeting in IRC, decide the tasks for the following weeks
  • log: http://duraspace.org/irclogs/index.php?date=2010-05-26
• 26th May - 9th June: Unit testing for package org.dspace.content.* . Weekly status reports sent to the DSpace GSoC lists, and the dspace-devel list.
• 9th June: 2nd meeting in IRC (21:00 UTC, #duraspace channel) to assert status of unit testing integrations and to discuss where there project should head next
• 12th July (Mid Term Evaluation)
• 9th August (End of Term)
• 9th August - 16th August (Final Evaluation): code fixes and documentation related to the project

Tools

• The Continuous Integration server may be Hudson (or Bamboo).

  • SONAR [http://www.sonarsource.org/ ] may be the code quality management tool

• All tests will be run automatically by Maven
  • Embedded webserver will be Jetty

  • Embedded database will be HyperSQL [http://hsqldb.org/ ]

• Functional Tests will use Selenium
• Unit Tests and Integration Tests will use Junit
  • JMock/Mockito will be used as mocking framework
  • HTMLUnit may be used if required
• Performance Tests will use ContiPerf

Thanks

This page has been created with help from Stuart Lewis, Scott Phillips and Gareth Waller. I want to thank them all for their comments. Some information has been taken from Wikipedia to make the text more complete. I'm to blame for errors in the text.

Feel free to contribute to this page!