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Test-driven development (TDD) and unit testing are methodologies that can greatly shorten functional verification time and increase quality. Engineers at Hewlett-Packard are currently applying these techniques with UVM-e (Universal Verification Methodology with IEEE 1647 e language) and getting good results—but it took a bit of work to get there.
The HP experience was described in a paper given at the recent DVCon 2014 conference. The paper was titled "Applying Test-Driven Development Methods to Design Verification Software in UVM-e." The authors are Doug Gibson and Mike Kontz, both of whom are design verification (DV) engineers at HP's Enterprise Server division, and both of whom are featured in the video clip below.
Inspired by Agile software development techniques, TDD is an approach in which specifications and tests are developed before the design is done (or even begun). Designers identify a feature to be developed, and then write a unit test that will verify that the feature meets particular specifications. The designer then starts coding and keeps going until all of the tests pass.
Unit tests are organized as series of individual tests, each housed within a test suite. Each test case within the test suite will cause a new, unique object to be created. The test case will be run against that object, and following a pass/fail result, the object under test will be destroyed.
A Solution for UVM-e
The HP Enterprise Server division recently adopted UVM-e "because we felt it was the most productive verification environment we could choose," Gibson said in the video below. But there was a problem. In the Specman e language environment, all units are constructed at time zero and they live for the time of the testbench. They cannot be constructed and destroyed at will, as a unit-test framework requires.
To solve this problem, Cadence developed a unit-test framework called the eUnit Testing Framework. The DVCon paper goes into considerable detail about the application of this framework and its advantages.
In the following video, Gibson and Kontz discuss the advantages of test-driven development for verification software, why their group adopted UVM and returned to the e language, why there was a need for a new framework, and what the framework allows HP to do. (If video fails to open, click here.)
Proceedings and speaker slides will be publicly available on April 24 at the DVCon website.
Other Cadence DVCon 2014 Blog Coverage
Jim Hogan at DVCon 2014: Functional Verification Faces "Abundant Chaos" from New Technologies
DVCon 2014 Panel: Did We Create the Functional Verification Gap?
DVCon 2014 Video: An Update on the UVM 1.2 Release
Lip-Bu Tan at DVCon 2014: EDA/Silicon Ecosystem Crucial to Innovation
DVCon 2014 in Review: Formal Verification, Value Chain, and the Industry's Future
DVCon 2014 Video: For Improved Verification, Think About the Flow
DVCon 2014: What's the Missing Piece in Verification?
DVCon 2014: How to Close the Verification Gap