Adhoc testing is informal, unstructured software testing that seeks to split the testing process to discover potential flaws or faults as soon as possible. Adhoc testing is performed randomly and is typically an unplanned activity that does not adhere to test design principles or documentation when creating test cases.
Error Guessing is a software testing approach that can perform adhoc testing without following any structure. Adhoc testing is performed without structure and does not adhere to any standardized testing methodology. This testing's goal is to identify flaws through random checking. People can "guess" the source of the error by performing error guessing.
Planning, documentation, or other processes are not necessary for this testing. Defects won't be mapped to test cases because this testing is meant to find flaws using a random approach without any documentation. As there aren't any test processes or requirements associated with the flaws, reproducing them can sometimes be quite challenging.