General Motors has begun pre-production of the Chevrolet Bolt EV, a notable milepost on the road towards producing a mass-market, all-electric car designed to compete with Tesla’s upcoming Model 3.

The first Chevy Bolt was sent down an assembly line at a plant in Orion, Mich., the same factory that makes the Buick Verona and Chevy Sonic, according to Michelle Malcho, spokeswoman for GM’s Chevy cars unit.

“For us, this shows movement,” Malcho tells Fortune. “We’re not just talking about it, we’re doing it. ”

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GM won’t start producing retail-ready versions of its all-electric Chevy Bolt until the end of this year. While pre-production versions of the Chevy Bolt are driveable, they can’t be sold to the public. Pre-production is a stage that allows engineers and factory workers to make sure parts fit, the manufacturing process works, and the dimensions on the car are right. For instance, workers might make sure the tool that installs the windshield works correctly, Malcho explains.

The testing is critical because both the Buick Verona and the Chevy Sonic will be assembled on the same line. Traditionally, it takes between six to 12 months for a GM car to go from pre-production to full production, Malcho said.

For the time being, GM released a teaser video and a few images on Tuesday to document the milestone.

GM has moved particularly fast on the development of the Chevy Bolt EV, which will have a 200-mile range and cost around $37,500 before government clean energy incentives. The company took the Bolt EV from concept to production-ready in only 12 months—lightning speed for a major automaker.

GM CEO and chairman Mary Barra introduced a production-version of the car in January at CES, the annual consumer electronics trade show in Las Vegas. In February, Barra followed up by unveiling a similar electric car, the Opel Ampera-e, for Europe.

However, the auto maker’s portfolio is still dominated by gas-powered cars and trucks. Yet the manpower and investment being placed on the Chevy Bolt illustrates the company’s shift over the past several years towards electric and plug-in hybrid electric cars. Options have steadily ramped up in the past five years.

In late 2010, the plug-in hybrid Chevy Volt hit the U.S. market. The Volt did see a drop in sales in 2015. Still, sales surged towards the end of the year with the streak continuing in to January and February thanks to demand for the next-generation 2016 Chevy Volt.