The present disclosure relates to managing assertions in program source code in an integrated development environment (IDE) tool. According to one embodiment, the IDE tool receives a request to execute an application built from source code of a development project from a user interacting with an integrated development environment (IDE) tool. The IDE tool identifies changes to one or more of the source code of the development project from a previous version of the one or more source code. Based on the changes to the source code, the IDE tool selectively identifies one or more assertions to insert in the source code based on the identified changes.