Quick-casual chain Briazz says it is supplying Chicago area Starbucks with sandwiches in a test meant to develop a lunch daypart at the coffee shops.

Forty Starbucks locations began selling Briazz sandwiches October 21 and will continue the test through December.

Briazz has 45 café locations in Los Angeles, San Francisco, Chicago, and Seattle, including a shop inside Starbucks world headquarters. In addition to restaurant service, Briazz offers deliver and catering.