ScalaTest Matcher/Property-based testing Live Coding materials
Introduction
This is a companion repository for a presentation I have cooked on various interesting matchers in ScalaTest. The
inspiration stemmed from observing that many people end up using the very basic matchers (equal, be), since
invariably it’s faster to just write it out than open up the docs.
Unfortunately, this leads to the tests, deprived of the more expressive features of ScalaTest, ending up with less self-documenting, having poorly-worded assertions ("true does not equal false"), or just being flat out incorect.
Description
The example domain models an API used to handle various kinds of sensors (temperature, radiation, etc.). Its hierarchies stem from the following roots:
-
Sensor- abstraction of a sensor, has a name (describing the type, e.g. "Temp"), alongidentifier, and anOption[Double]value. Can be initialized or not. -
SensorCollector- mostly a trivial container for `Sensor`s, subtypes contain some extra functionality. -
SensorDataPoint- used for Property-based tests, a single data point with a timestamp and a value -
SensorDataDisplay- a sortable container for `SensorDataPoint`s.
There are two test classes (both a FlatSpec), designed to be viewed side by side:
-
GoofusTest- contains the complete suite of test cases written naïvely or otherwise without a care. -
GallantTest- contains the "correct" form of the same suite of classes, rewritten with a fuller usage of ScalaTest features.
It is important to note that both the domain classes and GoofusTest have deliberate errors, mistakes, and omissions - this
is to showcase various issues relating to assertion error output, test subcases, etc. .
License
See LICENSE.