Testing examples

• Hardcoded input
• Hardcoded expected output
• Assert.AreEqual(expected, actual)

Testing examples

Testing examples

Testing properties

1. Write specification using properties
2. ???
3. Profit!

How?

Edge Cases

v

Equivalence Classes

Hardcoded input

v

Random input (within an equivalence class)

Hardcoded "magic" output

v

Inverse operations, idempotence, commutativity...

FsCheck

• Randomized testing library
• Built-in generators for many types
• Can easily generate complex values too
• Standalone or integrated with many testing libs

• Generate input
• Execute test
• Verify properties

Arbitrary = Generator + Shrinker

• Generate -> find error -> shrink

Advanced features

• Value classification
• Model-based testing