TL;DR

There are cases when the system under test is so complex, so it could only be tested by creating handcrafted oracle or human observation oracle. The post is aligned with the Black Box Software Testing Foundations course (BBST) designed by Rebecca Fiedler, Cem Kaner, and James Bach.

Despite all the hype with automated testing, there are cases when you can solve testing problems only using skilfull pair of software tester hands.

For example, what would be your oracle for the 3D model of the house in AutoCAD? How could you tell us that we have a problem with a house model in the above photo?

You need an AutoCAD designer that would be able:

• to handcraft acceptable results for an AutoCAD house model using AutoCAD features and commands
• where this is not possible, that software tester must be able to make decisions based on observations whether the house model is acceptable.

Advantages

Handcrafted oracles can be well understood and documented. This approach works for complex systems under test.

Disadvantages

This process is slow, expensive with high maintenance costs. If we do not have an experienced AutoCAD person, his wrong judgments could quickly lose credibility.