That's my point, we're yet to see how the packs go. Tesla did it all in-house whereas GM outsourced, another obvious difference. And I never said Tesla didn't test the pack. I'm just impressed by GM's proprietary software and how they went about testing the TWO packs.
Ah, I see what you mean. GM's testing is more of a result in that they have a competition between two suppliers, they are using newer chemistry while Tesla is using very established conventional li-ion, and they actually have to supply a 10 year warranty, which involves probably more extensive testing than the 5 year life of the Tesla.
This pdf mentions:
"Upon completion of our design, we collaborated with an outside firm known for expertise in lithium-ion batteries to perform hundreds of tests to validate the abuse tolerance and effectiveness of our design."
http://www.teslamotors.com/display_data/TeslaRoadsterBatterySystem.pdf
Seems like they did rely on some third party help, but most of the results obviously ended up internal.
But looking over the tests on the Volt batteries, there were accelerated life-cycle tests, climate (temperature) testing, and shock and vibration testing. I'm fairly certain Tesla did all of those kind of tests in one way or the other. Yes, we don't know much about the results, except they "passed".
This one mentions calendar and cycle life (makes it sound like they relied on the calendar and cycle life of the battery cells themselves, designed the pack to keep them at optimal condition and didn't sound like they did testing):
Tesla Motors - think
This blog post mentions temperature testing for the whole car:
Tesla Motors - touch
This blog post mentions shock and vibration testing for the batteries:
Tesla Motors - touch
The Volt testing doesn't really mention safety testing, but I suppose similar to how Tesla relied on battery cell specs to explain calendar and cycle life, GM relied on the safety specs of the battery cells themselves for safety (or more likely they tested safety, but didn't show it or Motor Trend didn't report, and just like it's more likely Tesla did do some battery life tests to ensure their claims are at least close). Tesla obviously had done safety tests, as mentioned in the same blog that talked about the shock and vibration testing.
The expectations of GM, a large mainstream automaker, is much more in that after 10 years the Volt is expected to STILL get 40 miles per charge. The Tesla is expected to have only around 80-70% of capacity after 5 years or 100,000 miles, whichever comes first. But testing on both is still fairly extensive, with the Volt showing more of the testing process (pretty much unprecedented amount of exposure to the development of a vehicle by a major automaker, but obviously the Volt is also a very good PR tool, with the hype on it probably even more than for the Roadster).