  The test pyramid is a conceptual model that describes how quality checks can
be organized to ensure coverage of all components of a system, at all scales.
Originally conceived to help aerospace engineers plan tests to determine how
material changes impact system integrity, the concept was gradually introduced
into software engineering. Today, the test pyramid is typically used to
illustrate that the majority of tests should be performed at the lowest (unit
test) level, with fewer integration tests, and even fewer acceptance tests
(which are the most expensive to produce, and the slowest to execute). Although
the value of acceptance tests and integration tests increasingly depends on the
integrity of the underlying data, models, and pipelines, software development
and data management organizations have traditionally been siloed and quality
assurance practice is not as mature in data operations as it is for software.
Companies that close this gap by developing cross-organizational systems will
create new competitive advantage and differentiation. By taking a more holistic
view of testing that crosses these boundaries, practitioners can help their
organizations close the gap.
