Litmus:Requirements

Introduction

Purpose

The purpose of this document is to capture in one place all the various requirements for the Litmus quality assurance (henceforth, QA) tool. In the past, many of the Netscape/Mozilla webtools have grown organically without much supporting documentation. While this document does not necessarily preclude this from happening with Litmus, it will at least give us an initial point of reference from which we can start design/development.

Document conventions

TBD.

Intended audience

This document is intended for QA staff, developers, build personnel, and sysadmins from the Mozilla Foundation, as well as community members interested in helping to improve the QA process for Mozilla products.

Additional information

• Litmus Litmus Main Page
• Test Result Format (DTD)
• Test case management ideas

Contact Info

Chris Cooper

References

• Le Vie, Jr., Donn. "Writing Software Requirements Specifications" TECHWR-L 7 July 2002. <http://www.techwr-l.com/techwhirl/magazine/writing/softwarerequirementspecs.html>.

Overall Description

Perspective

Mozilla testing resources, i.e. staff, are spread pretty thin. Even with some community support, the turnaround time for smoke testing and basic functional testing (BFT) for release candidates can take several days (the smoketests and BFTs are not currently automated). If regressions or new bugs are found during the testing process, the cycle can be even longer.

An existing tool, Testrunner, helps with the administration of this process, but the tool is somewhat limited. Testrunner has the concept of a "test run" as a single instance of testing, but these test runs must be manually cloned for each new testing cycle on a per-platform basis. Testrunner also does not let multiple users combine their efforts to work on a single test run; each user must have a separate test run, or have their results collated by a single "superuser."

The individual tests that make up a test run are not stored anywhere in Testrunner. Instead, test lists must me be kept in sync with external test repositories manually. This has made it impossible for any kind of automation to be built into Testrunner.

There is also no way to do any meaningful querying or reporting on historical test results using Testrunner. On top of all this, Testrunner is tied intimately to specific versions of Bugzilla; small changes to Bugzilla can cause Testrunner to stop working.

Bob Clary has a XUL-based test harness, called Spider, which he has used to automate the testing of many Document Object Model (DOM) and Javascript (JS) engine tests, but there has never been a central repository for test results, so his results have been posted to his personal testing website.

Developers often would like to have testing done to verify a given change or patch. Historically, this has not often been possible due to the constant demands on the QA team.

Addressing these shortcomings in the current tools (or the lack of tools, in general) will do much to streamline the QA process for Mozilla. This should have the desirable side effect of freeing up QA staff to work on more interesting things, e.g. harder edge-case testing, incoming bug verification and triage, community interaction, etc.

Functions

The new QA tool, Litmus, is meant to address these problems by:

• serving as a repository for test cases, with all the inherent management abilities that implies;
• serving as a repository for test results, carrying over the best features of Testrunner, e.g. test lists, division of labor, etc.;
• providing a query interface for viewing, reporting on, and comparing test results;
• providing a request interface whereby developers can queue testing requests for patches, fixes, and regressions;
• managing the automation of testing requests — one-time, and recurring (e.g. from tinderbox) — on a new group of dedicated testing servers, managing request priorities appropriately;
• exposing an API to allow developers to work with the various tools easily outside of a graphical environment;
• making it easier for casual testers to assist with testing Mozilla products.

User classes and characteristics

Litmus will attract the following types of users:

• Sysadmins
  These power users will be responsible for the maintenance of the underlying machines, and will likely be doing so from the command line. They will be primarily interested in how easy Litmus is to setup and install, CPU/disk space/network usage/database usage by the Litmus daemon and web tool, and any security implications that Litmus exposes.
• Litmus Maintainers
  This is a class of sysadmins who are solely responsible for the upkeep of the Litmus tool itself. They will likely have intimate knowledge of its inner working and will be able to/responsible for fixing bugs in Litmus itself.
• Release Engineers
  Given their role, these users will be primarily interested in the status of automated testing for release candidates, with the ability to compare test results between two different release candidates. They will also want the ability to pre-empt tests in progress if release testing is needed immediately. These users will have a history of using various existing web tools, e.g. tinderbox, bonsai, LXR, so they can be expected to adapt to a new web tool quickly.
• QA Staff
  Existing QA staff will already be familiar with Testrunner, which should ease the transition to a new web tool. This user class will have experience running tests both by hand and using the automated Spider tool. Because of this, most of these users will have developed an intuitive feel for what constitutes a valid testing result.
• Core Mozilla Developers
  Core developers will already be familiar with web tools such as Bugzilla and tinderbox. Due to their familiarity with Bugzilla, they will expect to see the same Product and Component categories in Litmus. This group might correspond to the set of developers with superreview and/or review status in Bugzilla. These users might expect to receive higher priority for testing requests that they submit.
• Mozilla Developers (including add-ons and extensions), Localizers
  The developers will already be familiar with web tools such as Bugzilla and tinderbox. Due to their familiarity with Bugzilla, they will expect to see the same Product and Component categories in Litmus.
• Testers
  
• Community-at-large
  

Operating environment

The main Litmus daemon and web tool will reside on an as-of-yet unpurchased machine. This machine will likely be running Linux to facilitate remote administration. The daemon and web tool will need to be designed to use the existing Linux Virtual Server (LVS) cluster.

External Interface Requirements

Hardware interfaces

At the recent Mozilla QA summit meeting (2005/06/21), it was decided to invest in a small cluster of machines that would serve as a test farm, similar in concept to the collection of machines that currently perform builds for Tinderbox.

The test farm will be made up of the following machines:

• Head Node (likely running Linux);
  • Linux Boxes (#?);
  • Mac XServes (#?);
  • Windows Boxes (#?).

Software interfaces

Adding more machines won't do anything to aid the testing burden in and of itself. Indeed, in the short-term, it will simply add more system administration overhead.

This is where we hope to see the biggest payoff in terms of automation. A main Litmus daemon will live on the head node. This daemon will be responsible for coordinating automated testing on the test farm machines, and collating results as they come in.