Explain why testing can only detect the presence of errors, not their absence.

Explanation: Testing is a set of activities that aim to detect software anomalies in a way that the errors can be discovered and correctes. The goal of software testing is to observe if the software behavior meet the requirements that they are expected to meet. Testing demonstrates to the developer that the software fullfils its requirements and it is a way to find out if it behaves in a incorrect, undesirable ou different form from the specifications.