Manual testing involves manually testing software by playing the role of an end user and using test cases to ensure correct behavior. It is important early in development when automation is not possible and for testing visual elements. A test plan is a document that outlines test objectives, workflows and processes while a test case specifies conditions to determine if a feature works as intended. Both exploratory and black/white box testing have pros and cons for finding bugs. Bugzilla is a bug tracking system that helps developers manage issues.