Realism impulse is a phenomenon in which test authors tend to favor realistic tests over more narrowly focused tests, typically in an effort to maximize the regression safety provided by the test.

This impulse continues to be strong, even in circumstances where sufficient regression safety is known to be provided elsewhere, the design of the given test suite doesn't call for that degree of realism, or where the risks of redundant coverage are otherwise well-understood.

Some have speculated that the root cause for this phenomenon is the use of the word "test" at all, and have put forward alternative vocabularies which avoid any preconceptions that "test" might carry.

Regardless, giving a term to the phenomenon can be useful in acknowledging its occurrences and potentially mitigating them.

References

• Video: To Mock or Not to Mock