Open Innovation (OI) has gained significant attention since the term was introduced in 2003. However, little is known whether general software testing processes are well suited for OI. An exploratory case study on the Acceptance Test Harness (ATH) is conducted to investigate OI testing activities of Jenkins. As far as the research methodology is concerned, we extracted the change log data of ATH followed by five interviews with key contributors in the development of ATH. The findings of the study are threefold. First, it highlights the key stakeholders involved in the development of ATH. Second, the study compares the ATH testing activities with ISO/IEC/IEEE testing process and presents a tailored process for software testing in OI. Finally, the study underlines some key challenges that software intensive organizations face while working with the testing in OI.