Introduction to Snapshot testing and using Verify.Xunit
Michiel and Oscar discuss snapshot testing, which is a type of data comparison test. Snapshot testing saves the output of a test and compares it to the output on subsequent runs to detect any changes. Michiel demonstrates how to write snapshot tests using Verify.Xunit library in C#. They show how snapshot testing can detect unintended changes or bugs introduced when code is modified. Their demo uses a simple employee mapper to map personal data to employee data. Bugs are intentionally introduced to demonstrate how snapshot testing fails when the output changes unexpectedly.