Tacit requirements are usually undocumented and often just expected. Deciphering such requirements comes with experience and practice. As a tester, it's important to test against tacit requirements and expectations as these often get ignored during the development lifecycle, time pressure, iterative updates, etc.
Examples of tacit requirements:
Examples of tacit requirements:
- Consistency: Uniform behaviour within and across features as well as other similar applications.
- History: Backward compatibility with previous versions. Changes to a feature will have no impact on other features.
- Familiar user expectations: Aligning user experience with industry norms or comparable products. Example: It is assumed that a double click will open a file.